Merge pull request #12354 from alalek:samples_find_file

modules/core/CMakeLists.txt

@@ -82,3 +82,47 @@ ocv_add_accuracy_tests()
 ocv_add_perf_tests()
 
 ocv_install_3rdparty_licenses(SoftFloat "${CMAKE_CURRENT_SOURCE_DIR}/3rdparty/SoftFloat/COPYING.txt")
+
+
+# generate data (samples data) config file
+set(OPENCV_DATA_CONFIG_FILE "${CMAKE_BINARY_DIR}/opencv_data_config.hpp")
+set(OPENCV_DATA_CONFIG_STR "")
+
+if(CMAKE_INSTALL_PREFIX)
+  set(OPENCV_DATA_CONFIG_STR "${OPENCV_DATA_CONFIG_STR}
+#define OPENCV_INSTALL_PREFIX \"${CMAKE_INSTALL_PREFIX}\"
+")
+endif()
+if(OPENCV_OTHER_INSTALL_PATH)
+  set(OPENCV_DATA_CONFIG_STR "${OPENCV_DATA_CONFIG_STR}
+#define OPENCV_DATA_INSTALL_PATH \"${OPENCV_OTHER_INSTALL_PATH}\"
+")
+endif()
+
+set(OPENCV_DATA_CONFIG_STR "${OPENCV_DATA_CONFIG_STR}
+#define OPENCV_BUILD_DIR \"${CMAKE_BINARY_DIR}\"
+")
+
+file(RELATIVE_PATH SOURCE_DIR_RELATIVE ${CMAKE_BINARY_DIR} ${CMAKE_SOURCE_DIR})
+set(OPENCV_DATA_CONFIG_STR "${OPENCV_DATA_CONFIG_STR}
+#define OPENCV_DATA_BUILD_DIR_SEARCH_PATHS \\
+    \"${SOURCE_DIR_RELATIVE}/\"
+")
+
+if(WIN32)
+  file(RELATIVE_PATH INSTALL_DATA_DIR_RELATIVE "${CMAKE_INSTALL_PREFIX}/${OPENCV_BIN_INSTALL_PATH}" "${CMAKE_INSTALL_PREFIX}/${OPENCV_OTHER_INSTALL_PATH}")
+else()
+  file(RELATIVE_PATH INSTALL_DATA_DIR_RELATIVE "${CMAKE_INSTALL_PREFIX}/${OPENCV_LIB_INSTALL_PATH}" "${CMAKE_INSTALL_PREFIX}/${OPENCV_OTHER_INSTALL_PATH}")
+endif()
+list(APPEND OPENCV_INSTALL_DATA_DIR_RELATIVE "${INSTALL_DATA_DIR_RELATIVE}")
+string(REPLACE ";" "\",\\\n    \"" OPENCV_INSTALL_DATA_DIR_RELATIVE_STR "\"${OPENCV_INSTALL_DATA_DIR_RELATIVE}\"")
+set(OPENCV_DATA_CONFIG_STR "${OPENCV_DATA_CONFIG_STR}
+#define OPENCV_INSTALL_DATA_DIR_RELATIVE ${OPENCV_INSTALL_DATA_DIR_RELATIVE_STR}
+")
+
+if(EXISTS "${OPENCV_DATA_CONFIG_FILE}")
+  file(READ "${OPENCV_DATA_CONFIG_FILE}" __content)
+endif()
+if(NOT OPENCV_DATA_CONFIG_STR STREQUAL "${__content}")
+  file(WRITE "${OPENCV_DATA_CONFIG_FILE}" "${OPENCV_DATA_CONFIG_STR}")
+endif()

modules/core/include/opencv2/core.hpp

@@ -75,6 +75,7 @@
         @defgroup core_utils_sse SSE utilities
         @defgroup core_utils_neon NEON utilities
         @defgroup core_utils_softfloat Softfloat support
+        @defgroup core_utils_samples Utility functions for OpenCV samples
     @}
     @defgroup core_opengl OpenGL interoperability
     @defgroup core_ipp Intel IPP Asynchronous C/C++ Converters

modules/core/include/opencv2/core/private.hpp

@@ -801,6 +801,82 @@ CV_EXPORTS InstrNode*   getCurrentNode();
 #define CV_INSTRUMENT_REGION(); CV_INSTRUMENT_REGION_();
 #endif
 
+namespace cv {
+
+namespace utils {
+
+//! @addtogroup core_utils
+//! @{
+
+/** @brief Try to find requested data file
+
+Search directories:
+
+1. Directories passed via `addDataSearchPath()`
+2. Check path specified by configuration parameter with "_HINT" suffix (name of environment variable).
+3. Check path specified by configuration parameter (name of environment variable).
+   If parameter value is not empty and nothing is found then stop searching.
+4. Detects build/install path based on:
+   a. current working directory (CWD)
+   b. and/or binary module location (opencv_core/opencv_world, doesn't work with static linkage)
+5. Scan `<source>/{,data}` directories if build directory is detected or the current directory is in source tree.
+6. Scan `<install>/share/OpenCV` directory if install directory is detected.
+
+@param relative_path Relative path to data file
+@param required Specify "file not found" handling.
+       If true, function prints information message and raises cv::Exception.
+       If false, function returns empty result
+@param configuration_parameter specify configuration parameter name. Default NULL value means "OPENCV_DATA_PATH".
+@return Returns path (absolute or relative to the current directory) or empty string if file is not found
+
+@note Implementation is not thread-safe.
+*/
+CV_EXPORTS
+cv::String findDataFile(const cv::String& relative_path, bool required = true,
+                        const char* configuration_parameter = NULL);
+
+/** @overload
+@param relative_path Relative path to data file
+@param configuration_parameter specify configuration parameter name. Default NULL value means "OPENCV_DATA_PATH".
+@param search_paths override addDataSearchPath() settings.
+@param subdir_paths override addDataSearchSubDirectory() settings.
+@return Returns path (absolute or relative to the current directory) or empty string if file is not found
+
+@note Implementation is not thread-safe.
+*/
+CV_EXPORTS
+cv::String findDataFile(const cv::String& relative_path,
+                        const char* configuration_parameter,
+                        const std::vector<String>* search_paths,
+                        const std::vector<String>* subdir_paths);
+
+/** @brief Override default search data path by adding new search location
+
+Use this only to override default behavior
+Passed paths are used in LIFO order.
+
+@param path Path to used samples data
+
+@note Implementation is not thread-safe.
+*/
+CV_EXPORTS void addDataSearchPath(const cv::String& path);
+
+/** @brief Append default search data sub directory
+
+General usage is to add OpenCV modules name (`<opencv_contrib>/modules/<name>/data` -> `modules/<name>/data` + `<name>/data`).
+Passed subdirectories are used in LIFO order.
+
+@param subdir samples data sub directory
+
+@note Implementation is not thread-safe.
+*/
+CV_EXPORTS void addDataSearchSubDirectory(const cv::String& subdir);
+
+//! @}
+
+} // namespace utils
+} // namespace cv
+
 //! @endcond
 
 #endif // OPENCV_CORE_PRIVATE_HPP

modules/core/include/opencv2/core/utility.hpp

@@ -1274,8 +1274,75 @@ enum FLAGS
 CV_EXPORTS void       setFlags(FLAGS modeFlags);
 static inline void    setFlags(int modeFlags) { setFlags((FLAGS)modeFlags); }
 CV_EXPORTS FLAGS      getFlags();
+
+} // namespace instr
+
+
+namespace samples {
+
+//! @addtogroup core_utils_samples
+// This section describes utility functions for OpenCV samples.
+//
+// @note Implementation of these utilities is not thread-safe.
+//
+//! @{
+
+/** @brief Try to find requested data file
+
+Search directories:
+
+1. Directories passed via `addSamplesDataSearchPath()`
+2. OPENCV_SAMPLES_DATA_PATH_HINT environment variable
+3. OPENCV_SAMPLES_DATA_PATH environment variable
+   If parameter value is not empty and nothing is found then stop searching.
+4. Detects build/install path based on:
+   a. current working directory (CWD)
+   b. and/or binary module location (opencv_core/opencv_world, doesn't work with static linkage)
+5. Scan `<source>/{,data,samples/data}` directories if build directory is detected or the current directory is in source tree.
+6. Scan `<install>/share/OpenCV` directory if install directory is detected.
+
+@see cv::utils::findDataFile
+
+@param relative_path Relative path to data file
+@param required Specify "file not found" handling.
+       If true, function prints information message and raises cv::Exception.
+       If false, function returns empty result
+@param silentMode Disables messages
+@return Returns path (absolute or relative to the current directory) or empty string if file is not found
+*/
+CV_EXPORTS_W cv::String findFile(const cv::String& relative_path, bool required = true, bool silentMode = false);
+
+CV_EXPORTS_W cv::String findFileOrKeep(const cv::String& relative_path, bool silentMode = false);
+
+inline cv::String findFileOrKeep(const cv::String& relative_path, bool silentMode)
+{
+    cv::String res = findFile(relative_path, false, silentMode);
+    if (res.empty())
+        return relative_path;
+    return res;
 }
 
+/** @brief Override search data path by adding new search location
+
+Use this only to override default behavior
+Passed paths are used in LIFO order.
+
+@param path Path to used samples data
+*/
+CV_EXPORTS_W void addSamplesDataSearchPath(const cv::String& path);
+
+/** @brief Append samples search data sub directory
+
+General usage is to add OpenCV modules name (`<opencv_contrib>/modules/<name>/samples/data` -> `<name>/samples/data` + `modules/<name>/samples/data`).
+Passed subdirectories are used in LIFO order.
+
+@param subdir samples data sub directory
+*/
+CV_EXPORTS_W void addSamplesDataSearchSubDirectory(const cv::String& subdir);
+
+//! @}
+} // namespace samples
+
 namespace utils {
 
 CV_EXPORTS int getThreadID();

modules/core/include/opencv2/core/utils/filesystem.hpp

@@ -16,6 +16,13 @@ CV_EXPORTS void remove_all(const cv::String& path);
 
 CV_EXPORTS cv::String getcwd();
 
+/** @brief Converts path p to a canonical absolute path
+ * Symlinks are processed if there is support for them on running platform.
+ *
+ * @param path input path. Target file/directory should exist.
+ */
+CV_EXPORTS cv::String canonical(const cv::String& path);
+
 /** Join path components */
 CV_EXPORTS cv::String join(const cv::String& base, const cv::String& path);
 

modules/core/src/utils/datafile.cpp

@@ -0,0 +1,398 @@
+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+
+#include "../precomp.hpp"
+
+#include "opencv_data_config.hpp"
+
+#include <vector>
+#include <fstream>
+
+#include <opencv2/core/utils/logger.defines.hpp>
+#undef CV_LOG_STRIP_LEVEL
+#define CV_LOG_STRIP_LEVEL CV_LOG_LEVEL_VERBOSE + 1
+#include "opencv2/core/utils/logger.hpp"
+#include "opencv2/core/utils/filesystem.hpp"
+
+#include <opencv2/core/utils/configuration.private.hpp>
+
+#ifdef _WIN32
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#undef small
+#undef min
+#undef max
+#undef abs
+#elif defined(__APPLE__)
+#include <TargetConditionals.h>
+#if TARGET_OS_MAC
+#include <dlfcn.h>
+#endif
+#endif
+
+namespace cv { namespace utils {
+
+static cv::Ptr< std::vector<cv::String> > g_data_search_path;
+static cv::Ptr< std::vector<cv::String> > g_data_search_subdir;
+
+static std::vector<cv::String>& _getDataSearchPath()
+{
+    if (g_data_search_path.empty())
+        g_data_search_path.reset(new std::vector<cv::String>());
+    return *(g_data_search_path.get());
+}
+
+static std::vector<cv::String>& _getDataSearchSubDirectory()
+{
+    if (g_data_search_subdir.empty())
+    {
+        g_data_search_subdir.reset(new std::vector<cv::String>());
+        g_data_search_subdir->push_back("data");
+        g_data_search_subdir->push_back("");
+    }
+    return *(g_data_search_subdir.get());
+}
+
+
+CV_EXPORTS void addDataSearchPath(const cv::String& path)
+{
+    if (utils::fs::isDirectory(path))
+        _getDataSearchPath().push_back(path);
+}
+CV_EXPORTS void addDataSearchSubDirectory(const cv::String& subdir)
+{
+    _getDataSearchSubDirectory().push_back(subdir);
+}
+
+static bool isPathSep(char c)
+{
+    return c == '/' || c == '\\';
+}
+static bool isSubDirectory_(const cv::String& base_path, const cv::String& path)
+{
+    size_t N = base_path.size();
+    if (N == 0)
+        return false;
+    if (isPathSep(base_path[N - 1]))
+        N--;
+    if (path.size() < N)
+        return false;
+    for (size_t i = 0; i < N; i++)
+    {
+        if (path[i] == base_path[i])
+            continue;
+        if (isPathSep(path[i]) && isPathSep(base_path[i]))
+            continue;
+        return false;
+    }
+    size_t M = path.size();
+    if (M > N)
+    {
+        if (!isPathSep(path[N]))
+            return false;
+    }
+    return true;
+}
+static bool isSubDirectory(const cv::String& base_path, const cv::String& path)
+{
+    bool res = isSubDirectory_(base_path, path);
+    CV_LOG_VERBOSE(NULL, 0, "isSubDirectory(): base: " << base_path << "  path: " << path << "  => result: " << (res ? "TRUE" : "FALSE"));
+    return res;
+}
+
+static cv::String getModuleLocation(const void* addr)
+{
+    CV_UNUSED(addr);
+#ifdef _WIN32
+    HMODULE m = 0;
+#if _WIN32_WINNT >= 0x0501
+    ::GetModuleHandleEx(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
+        reinterpret_cast<LPCTSTR>(addr),
+        &m);
+#endif
+    if (m)
+    {
+        char path[MAX_PATH];
+        const size_t path_size = sizeof(path)/sizeof(*path);
+        size_t sz = GetModuleFileNameA(m, path, path_size); // no unicode support
+        if (sz > 0 && sz < path_size)
+        {
+            path[sz] = '\0';
+            return cv::String(path);
+        }
+    }
+#elif defined(__linux__)
+    std::ifstream fs("/proc/self/maps");
+    std::string line;
+    while (std::getline(fs, line, '\n'))
+    {
+        long long int addr_begin = 0, addr_end = 0;
+        if (2 == sscanf(line.c_str(), "%llx-%llx", &addr_begin, &addr_end))
+        {
+            if ((intptr_t)addr >= (intptr_t)addr_begin && (intptr_t)addr < (intptr_t)addr_end)
+            {
+                size_t pos = line.rfind("  "); // 2 spaces
+                if (pos == cv::String::npos)
+                    pos = line.rfind(' '); // 1 spaces
+                else
+                    pos++;
+                if (pos == cv::String::npos)
+                {
+                    CV_LOG_DEBUG(NULL, "Can't parse module path: '" << line << '\'');
+                }
+                return line.substr(pos + 1);
+            }
+        }
+    }
+#elif defined(__APPLE__)
+# if TARGET_OS_MAC
+    Dl_info info;
+    if (0 != dladdr(addr, &info))
+    {
+        return cv::String(info.dli_fname);
+    }
+# endif
+#else
+    // not supported, skip
+#endif
+    return cv::String();
+}
+
+cv::String findDataFile(const cv::String& relative_path,
+                        const char* configuration_parameter,
+                        const std::vector<String>* search_paths,
+                        const std::vector<String>* subdir_paths)
+{
+    configuration_parameter = configuration_parameter ? configuration_parameter : "OPENCV_DATA_PATH";
+    CV_LOG_DEBUG(NULL, cv::format("utils::findDataFile('%s', %s)", relative_path.c_str(), configuration_parameter));
+
+#define TRY_FILE_WITH_PREFIX(prefix) \
+{ \
+    cv::String path = utils::fs::join(prefix, relative_path); \
+    CV_LOG_DEBUG(NULL, cv::format("... Line %d: trying open '%s'", __LINE__, path.c_str())); \
+    FILE* f = fopen(path.c_str(), "rb"); \
+    if(f) { \
+        fclose(f); \
+        return path; \
+    } \
+}
+
+
+    // Step 0: check current directory or absolute path at first
+    TRY_FILE_WITH_PREFIX("");
+
+
+    // Step 1
+    const std::vector<cv::String>& search_path = search_paths ? *search_paths : _getDataSearchPath();
+    for(size_t i = search_path.size(); i > 0; i--)
+    {
+        const cv::String& prefix = search_path[i - 1];
+        TRY_FILE_WITH_PREFIX(prefix);
+    }
+
+    const std::vector<cv::String>& search_subdir = subdir_paths ? *subdir_paths : _getDataSearchSubDirectory();
+
+
+    // Step 2
+    const cv::String configuration_parameter_s(configuration_parameter ? configuration_parameter : "");
+    const cv::utils::Paths& search_hint = configuration_parameter_s.empty() ? cv::utils::Paths()
+                                          : getConfigurationParameterPaths((configuration_parameter_s + "_HINT").c_str());
+    for (size_t k = 0; k < search_hint.size(); k++)
+    {
+        cv::String datapath = search_hint[k];
+        if (datapath.empty())
+            continue;
+        if (utils::fs::isDirectory(datapath))
+        {
+            CV_LOG_DEBUG(NULL, "utils::findDataFile(): trying " << configuration_parameter << "_HINT=" << datapath);
+            for(size_t i = search_subdir.size(); i > 0; i--)
+            {
+                const cv::String& subdir = search_subdir[i - 1];
+                cv::String prefix = utils::fs::join(datapath, subdir);
+                TRY_FILE_WITH_PREFIX(prefix);
+            }
+        }
+        else
+        {
+            CV_LOG_WARNING(NULL, configuration_parameter << "_HINT is specified but it is not a directory: " << datapath);
+        }
+    }
+
+
+    // Step 3
+    const cv::utils::Paths& override_paths = configuration_parameter_s.empty() ? cv::utils::Paths()
+                                           : getConfigurationParameterPaths(configuration_parameter);
+    for (size_t k = 0; k < override_paths.size(); k++)
+    {
+        cv::String datapath = override_paths[k];
+        if (datapath.empty())
+            continue;
+        if (utils::fs::isDirectory(datapath))
+        {
+            CV_LOG_DEBUG(NULL, "utils::findDataFile(): trying " << configuration_parameter << "=" << datapath);
+            for(size_t i = search_subdir.size(); i > 0; i--)
+            {
+                const cv::String& subdir = search_subdir[i - 1];
+                cv::String prefix = utils::fs::join(datapath, subdir);
+                TRY_FILE_WITH_PREFIX(prefix);
+            }
+        }
+        else
+        {
+            CV_LOG_WARNING(NULL, configuration_parameter << " is specified but it is not a directory: " << datapath);
+        }
+    }
+    if (!override_paths.empty())
+    {
+        CV_LOG_INFO(NULL, "utils::findDataFile(): can't find data file via " << configuration_parameter << " configuration override: " << relative_path);
+        return cv::String();
+    }
+
+
+    // Steps: 4, 5, 6
+    cv::String cwd = utils::fs::getcwd();
+    cv::String build_dir(OPENCV_BUILD_DIR);
+    bool has_tested_build_directory = false;
+    if (isSubDirectory(build_dir, cwd) || isSubDirectory(utils::fs::canonical(build_dir), utils::fs::canonical(cwd)))
+    {
+        CV_LOG_DEBUG(NULL, "utils::findDataFile(): the current directory is build sub-directory: " << cwd);
+        const char* build_subdirs[] = { OPENCV_DATA_BUILD_DIR_SEARCH_PATHS };
+        for (size_t k = 0; k < sizeof(build_subdirs)/sizeof(build_subdirs[0]); k++)
+        {
+            CV_LOG_DEBUG(NULL, "utils::findDataFile(): <build>/" << build_subdirs[k]);
+            cv::String datapath = utils::fs::join(build_dir, build_subdirs[k]);
+            if (utils::fs::isDirectory(datapath))
+            {
+                for(size_t i = search_subdir.size(); i > 0; i--)
+                {
+                    const cv::String& subdir = search_subdir[i - 1];
+                    cv::String prefix = utils::fs::join(datapath, subdir);
+                    TRY_FILE_WITH_PREFIX(prefix);
+                }
+            }
+        }
+        has_tested_build_directory = true;
+    }
+
+    cv::String source_dir;
+    cv::String try_source_dir = cwd;
+    for (int levels = 0; levels < 3; ++levels)
+    {
+        if (utils::fs::exists(utils::fs::join(try_source_dir, "modules/core/include/opencv2/core/version.hpp")))
+        {
+            source_dir = try_source_dir;
+            break;
+        }
+        try_source_dir = utils::fs::join(try_source_dir, "/..");
+    }
+    if (!source_dir.empty())
+    {
+        CV_LOG_DEBUG(NULL, "utils::findDataFile(): the current directory is source sub-directory: " << source_dir);
+        CV_LOG_DEBUG(NULL, "utils::findDataFile(): <source>" << source_dir);
+        cv::String datapath = source_dir;
+        if (utils::fs::isDirectory(datapath))
+        {
+            for(size_t i = search_subdir.size(); i > 0; i--)
+            {
+                const cv::String& subdir = search_subdir[i - 1];
+                cv::String prefix = utils::fs::join(datapath, subdir);
+                TRY_FILE_WITH_PREFIX(prefix);
+            }
+        }
+    }
+
+    cv::String module_path = getModuleLocation((void*)getModuleLocation);  // use code addr, doesn't work with static linkage!
+    CV_LOG_DEBUG(NULL, "Detected module path: '" << module_path << '\'');
+
+    if (!has_tested_build_directory &&
+        (isSubDirectory(build_dir, module_path) || isSubDirectory(utils::fs::canonical(build_dir), utils::fs::canonical(module_path)))
+    )
+    {
+        CV_LOG_DEBUG(NULL, "utils::findDataFile(): the binary module directory is build sub-directory: " << module_path);
+        const char* build_subdirs[] = { OPENCV_DATA_BUILD_DIR_SEARCH_PATHS };
+        for (size_t k = 0; k < sizeof(build_subdirs)/sizeof(build_subdirs[0]); k++)
+        {
+            CV_LOG_DEBUG(NULL, "utils::findDataFile(): <build>/" << build_subdirs[k]);
+            cv::String datapath = utils::fs::join(build_dir, build_subdirs[k]);
+            if (utils::fs::isDirectory(datapath))
+            {
+                for(size_t i = search_subdir.size(); i > 0; i--)
+                {
+                    const cv::String& subdir = search_subdir[i - 1];
+                    cv::String prefix = utils::fs::join(datapath, subdir);
+                    TRY_FILE_WITH_PREFIX(prefix);
+                }
+            }
+        }
+    }
+
+#if defined OPENCV_INSTALL_DATA_DIR_RELATIVE
+    if (!module_path.empty())  // require module path
+    {
+        size_t pos = module_path.rfind('/');
+        if (pos == cv::String::npos)
+            pos = module_path.rfind('\\');
+        cv::String module_dir = (pos == cv::String::npos) ? module_path : module_path.substr(0, pos);
+        const char* install_subdirs[] = { OPENCV_INSTALL_DATA_DIR_RELATIVE };
+        for (size_t k = 0; k < sizeof(install_subdirs)/sizeof(install_subdirs[0]); k++)
+        {
+            cv::String datapath = utils::fs::join(module_dir, install_subdirs[k]);
+            CV_LOG_DEBUG(NULL, "utils::findDataFile(): trying install path (from binary path): " << datapath);
+            if (utils::fs::isDirectory(datapath))
+            {
+                for(size_t i = search_subdir.size(); i > 0; i--)
+                {
+                    const cv::String& subdir = search_subdir[i - 1];
+                    cv::String prefix = utils::fs::join(datapath, subdir);
+                    TRY_FILE_WITH_PREFIX(prefix);
+                }
+            }
+            else
+            {
+                CV_LOG_DEBUG(NULL, "utils::findDataFile(): ... skip, not a valid directory: " << datapath);
+            }
+        }
+    }
+#endif
+
+#if defined OPENCV_INSTALL_PREFIX && defined OPENCV_DATA_INSTALL_PATH
+    cv::String install_dir(OPENCV_INSTALL_PREFIX);
+    // use core/world module path and verify that library is running from installation directory
+    // It is neccessary to avoid touching of unrelated common /usr/local path
+    if (module_path.empty()) // can't determine
+        module_path = install_dir;
+    if (isSubDirectory(install_dir, module_path) || isSubDirectory(utils::fs::canonical(install_dir), utils::fs::canonical(module_path)))
+    {
+        cv::String datapath = utils::fs::join(install_dir, OPENCV_DATA_INSTALL_PATH);
+        if (utils::fs::isDirectory(datapath))
+        {
+            CV_LOG_DEBUG(NULL, "utils::findDataFile(): trying install path: " << datapath);
+            for(size_t i = search_subdir.size(); i > 0; i--)
+            {
+                const cv::String& subdir = search_subdir[i - 1];
+                cv::String prefix = utils::fs::join(datapath, subdir);
+                TRY_FILE_WITH_PREFIX(prefix);
+            }
+        }
+    }
+#endif
+
+    return cv::String();  // not found
+}
+
+cv::String findDataFile(const cv::String& relative_path, bool required, const char* configuration_parameter)
+{
+    CV_LOG_DEBUG(NULL, cv::format("cv::utils::findDataFile('%s', %s, %s)",
+                                  relative_path.c_str(), required ? "true" : "false",
+                                  configuration_parameter ? configuration_parameter : "NULL"));
+    cv::String result = cv::utils::findDataFile(relative_path,
+                                                configuration_parameter,
+                                                NULL,
+                                                NULL);
+    if (result.empty() && required)
+        CV_Error(cv::Error::StsError, cv::format("OpenCV: Can't find required data file: %s", relative_path.c_str()));
+    return result;
+}
+
+}} // namespace

modules/core/src/utils/filesystem.cpp

@@ -85,6 +85,20 @@ cv::String join(const cv::String& base, const cv::String& path)
 
 #if OPENCV_HAVE_FILESYSTEM_SUPPORT
 
+cv::String canonical(const cv::String& path)
+{
+#ifdef _WIN32
+    const char* result = _fullpath(NULL, path.c_str(), 0);
+#else
+    const char* result = realpath(path.c_str(), NULL);
+#endif
+    if (result)
+        return cv::String(result);
+    // no error handling, just return input
+    return path;
+}
+
+
 bool exists(const cv::String& path)
 {
     CV_INSTRUMENT_REGION();
@@ -543,11 +557,12 @@ cv::String getCacheDirectory(const char* sub_directory_name, const char* configu
 
 #else
 #define NOT_IMPLEMENTED CV_Error(Error::StsNotImplemented, "");
-CV_EXPORTS bool exists(const cv::String& /*path*/) { NOT_IMPLEMENTED }
-CV_EXPORTS void remove_all(const cv::String& /*path*/) { NOT_IMPLEMENTED }
-CV_EXPORTS bool createDirectory(const cv::String& /*path*/) { NOT_IMPLEMENTED }
-CV_EXPORTS bool createDirectories(const cv::String& /*path*/) { NOT_IMPLEMENTED }
-CV_EXPORTS cv::String getCacheDirectory(const char* /*sub_directory_name*/, const char* /*configuration_name = NULL*/) { NOT_IMPLEMENTED }
+cv::String canonical(const cv::String& /*path*/) { NOT_IMPLEMENTED }
+bool exists(const cv::String& /*path*/) { NOT_IMPLEMENTED }
+void remove_all(const cv::String& /*path*/) { NOT_IMPLEMENTED }
+bool createDirectory(const cv::String& /*path*/) { NOT_IMPLEMENTED }
+bool createDirectories(const cv::String& /*path*/) { NOT_IMPLEMENTED }
+cv::String getCacheDirectory(const char* /*sub_directory_name*/, const char* /*configuration_name = NULL*/) { NOT_IMPLEMENTED }
 #undef NOT_IMPLEMENTED
 #endif // OPENCV_HAVE_FILESYSTEM_SUPPORT
 

modules/core/src/utils/samples.cpp

@@ -0,0 +1,67 @@
+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+
+#include "../precomp.hpp"
+
+#include <vector>
+
+#include <opencv2/core/utils/logger.defines.hpp>
+#undef CV_LOG_STRIP_LEVEL
+#define CV_LOG_STRIP_LEVEL CV_LOG_LEVEL_VERBOSE + 1
+#include "opencv2/core/utils/logger.hpp"
+#include "opencv2/core/utils/filesystem.hpp"
+
+namespace cv { namespace samples {
+
+static cv::Ptr< std::vector<cv::String> > g_data_search_path;
+static cv::Ptr< std::vector<cv::String> > g_data_search_subdir;
+
+static std::vector<cv::String>& _getDataSearchPath()
+{
+    if (g_data_search_path.empty())
+        g_data_search_path.reset(new std::vector<cv::String>());
+    return *(g_data_search_path.get());
+}
+
+static std::vector<cv::String>& _getDataSearchSubDirectory()
+{
+    if (g_data_search_subdir.empty())
+    {
+        g_data_search_subdir.reset(new std::vector<cv::String>());
+        g_data_search_subdir->push_back("samples/data");
+        g_data_search_subdir->push_back("data");
+        g_data_search_subdir->push_back("");
+    }
+    return *(g_data_search_subdir.get());
+}
+
+
+CV_EXPORTS void addSamplesDataSearchPath(const cv::String& path)
+{
+    if (utils::fs::isDirectory(path))
+        _getDataSearchPath().push_back(path);
+}
+CV_EXPORTS void addSamplesDataSearchSubDirectory(const cv::String& subdir)
+{
+    _getDataSearchSubDirectory().push_back(subdir);
+}
+
+cv::String findFile(const cv::String& relative_path, bool required, bool silentMode)
+{
+    CV_LOG_DEBUG(NULL, cv::format("cv::samples::findFile('%s', %s)", relative_path.c_str(), required ? "true" : "false"));
+    cv::String result = cv::utils::findDataFile(relative_path,
+                                                "OPENCV_SAMPLES_DATA_PATH",
+                                                &_getDataSearchPath(),
+                                                &_getDataSearchSubDirectory());
+    if (result != relative_path && !silentMode)
+    {
+        CV_LOG_WARNING(NULL, "cv::samples::findFile('" << relative_path << "') => '" << result << "'");
+    }
+    if (result.empty() && required)
+        CV_Error(cv::Error::StsError, cv::format("OpenCV samples: Can't find required data file: %s", relative_path.c_str()));
+    return result;
+}
+
+
+}} // namespace

modules/core/test/test_utils.cpp

@@ -2,6 +2,7 @@
 // It is subject to the license terms in the LICENSE file found in the top-level directory
 // of this distribution and at http://opencv.org/license.html.
 #include "test_precomp.hpp"
+#include "opencv2/core/utils/logger.hpp"
 
 namespace opencv_test { namespace {
 
@@ -283,4 +284,21 @@ TEST(CommandLineParser, testScalar)
     EXPECT_EQ(parser.get<Scalar>("s5"), Scalar(5, -4, 3, 2));
 }
 
+TEST(Samples, findFile)
+{
+    cv::utils::logging::LogLevel prev = cv::utils::logging::setLogLevel(cv::utils::logging::LOG_LEVEL_VERBOSE);
+    cv::String path;
+    ASSERT_NO_THROW(path = samples::findFile("lena.jpg", false));
+    EXPECT_NE(std::string(), path.c_str());
+    cv::utils::logging::setLogLevel(prev);
+}
+
+TEST(Samples, findFile_missing)
+{
+    cv::utils::logging::LogLevel prev = cv::utils::logging::setLogLevel(cv::utils::logging::LOG_LEVEL_VERBOSE);
+    cv::String path;
+    ASSERT_ANY_THROW(path = samples::findFile("non-existed.file", true));
+    cv::utils::logging::setLogLevel(prev);
+}
+
 }} // namespace

modules/python/test/test_misc.py

@@ -84,6 +84,23 @@ class Arguments(NewOpenCVTests):
         self.assertEqual(res4, "InputArrayOfArrays: empty()=false kind=0x00050000 flags=0x01050000 total(-1)=3 dims(-1)=1 size(-1)=3x1 type(0)=CV_32FC2 dims(0)=2 size(0)=3x1 type(0)=CV_32FC2")
 
 
+class SamplesFindFile(NewOpenCVTests):
+
+    def test_ExistedFile(self):
+        res = cv.samples.findFile('lena.jpg', False)
+        self.assertNotEqual(res, '')
+
+    def test_MissingFile(self):
+        res = cv.samples.findFile('non_existed.file', False)
+        self.assertEqual(res, '')
+
+    def test_MissingFileException(self):
+        try:
+            res = cv.samples.findFile('non_existed.file', True)
+            self.assertEqual("Dead code", 0)
+        except cv.error as _e:
+            pass
+
 
 if __name__ == '__main__':
     NewOpenCVTests.bootstrap()

samples/cpp/application_trace.cpp

@@ -41,7 +41,7 @@ int main(int argc, char** argv)
     if (video.size() == 1 && isdigit(video[0]))
         capture.open(parser.get<int>("@video"));
     else
-        capture.open(video);
+        capture.open(samples::findFileOrKeep(video));  // keep GStreamer pipelines
     int nframes = 0;
     if (capture.isOpened())
     {

samples/cpp/bgfg_segm.cpp

@@ -38,7 +38,10 @@ int main(int argc, const char** argv)
     if (file.empty())
         cap.open(camera);
     else
+    {
+        file = samples::findFileOrKeep(file);  // ignore gstreamer pipelines
         cap.open(file.c_str());
+    }
     if (!cap.isOpened())
     {
         cout << "Can not open video stream: '" << (file.empty() ? "<camera>" : file) << "'" << endl;

samples/cpp/calibration.cpp

@@ -254,12 +254,31 @@ static bool readStringList( const string& filename, vector<string>& l )
     FileStorage fs(filename, FileStorage::READ);
     if( !fs.isOpened() )
         return false;
+    size_t dir_pos = filename.rfind('/');
+    if (dir_pos == string::npos)
+        dir_pos = filename.rfind('\\');
     FileNode n = fs.getFirstTopLevelNode();
     if( n.type() != FileNode::SEQ )
         return false;
     FileNodeIterator it = n.begin(), it_end = n.end();
     for( ; it != it_end; ++it )
-        l.push_back((string)*it);
+    {
+        string fname = (string)*it;
+        if (dir_pos != string::npos)
+        {
+            string fpath = samples::findFile(filename.substr(0, dir_pos + 1) + fname, false);
+            if (fpath.empty())
+            {
+                fpath = samples::findFile(fname);
+            }
+            fname = fpath;
+        }
+        else
+        {
+            fname = samples::findFile(fname);
+        }
+        l.push_back(fname);
+    }
     return true;
 }
 
@@ -383,10 +402,10 @@ int main( int argc, char** argv )
 
     if( !inputFilename.empty() )
     {
-        if( !videofile && readStringList(inputFilename, imageList) )
+        if( !videofile && readStringList(samples::findFile(inputFilename), imageList) )
             mode = CAPTURING;
         else
-            capture.open(inputFilename);
+            capture.open(samples::findFileOrKeep(inputFilename));
     }
     else
         capture.open(cameraId);

samples/cpp/cloning_demo.cpp

@@ -17,8 +17,7 @@
 * The program takes as input a source and a destination image (for 1-3 methods)
 * and outputs the cloned image.
 *
-* Download test images from opencv_extra folder @github.
-*
+* Download test images from opencv_extra repository.
 */
 
 #include "opencv2/photo.hpp"
@@ -27,7 +26,6 @@
 #include "opencv2/highgui.hpp"
 #include "opencv2/core.hpp"
 #include <iostream>
-#include <stdlib.h>
 
 using namespace std;
 using namespace cv;
@@ -35,6 +33,7 @@ using namespace cv;
 int main()
 {
     cout << endl;
+    cout << "Note: specify OPENCV_SAMPLES_DATA_PATH_HINT=<opencv_extra>/testdata/cv" << endl << endl;
     cout << "Cloning Module" << endl;
     cout << "---------------" << endl;
     cout << "Options: " << endl;
@@ -54,9 +53,9 @@ int main()
     if(num == 1)
     {
         string folder =  "cloning/Normal_Cloning/";
-        string original_path1 = folder + "source1.png";
-        string original_path2 = folder + "destination1.png";
-        string original_path3 = folder + "mask.png";
+        string original_path1 = samples::findFile(folder + "source1.png");
+        string original_path2 = samples::findFile(folder + "destination1.png");
+        string original_path3 = samples::findFile(folder + "mask.png");
 
         Mat source = imread(original_path1, IMREAD_COLOR);
         Mat destination = imread(original_path2, IMREAD_COLOR);
@@ -86,14 +85,14 @@ int main()
         seamlessClone(source, destination, mask, p, result, 1);
 
         imshow("Output",result);
-        imwrite(folder + "cloned.png", result);
+        imwrite("cloned.png", result);
     }
     else if(num == 2)
     {
         string folder = "cloning/Mixed_Cloning/";
-        string original_path1 = folder + "source1.png";
-        string original_path2 = folder + "destination1.png";
-        string original_path3 = folder + "mask.png";
+        string original_path1 = samples::findFile(folder + "source1.png");
+        string original_path2 = samples::findFile(folder + "destination1.png");
+        string original_path3 = samples::findFile(folder + "mask.png");
 
         Mat source = imread(original_path1, IMREAD_COLOR);
         Mat destination = imread(original_path2, IMREAD_COLOR);
@@ -123,14 +122,14 @@ int main()
         seamlessClone(source, destination, mask, p, result, 2);
 
         imshow("Output",result);
-        imwrite(folder + "cloned.png", result);
+        imwrite("cloned.png", result);
     }
     else if(num == 3)
     {
         string folder = "cloning/Monochrome_Transfer/";
-        string original_path1 = folder + "source1.png";
-        string original_path2 = folder + "destination1.png";
-        string original_path3 = folder + "mask.png";
+        string original_path1 = samples::findFile(folder + "source1.png");
+        string original_path2 = samples::findFile(folder + "destination1.png");
+        string original_path3 = samples::findFile(folder + "mask.png");
 
         Mat source = imread(original_path1, IMREAD_COLOR);
         Mat destination = imread(original_path2, IMREAD_COLOR);
@@ -160,13 +159,13 @@ int main()
         seamlessClone(source, destination, mask, p, result, 3);
 
         imshow("Output",result);
-        imwrite(folder + "cloned.png", result);
+        imwrite("cloned.png", result);
     }
     else if(num == 4)
     {
-        string folder = "cloning/Color_Change/";
-        string original_path1 = folder + "source1.png";
-        string original_path2 = folder + "mask.png";
+        string folder = "cloning/color_change/";
+        string original_path1 = samples::findFile(folder + "source1.png");
+        string original_path2 = samples::findFile(folder + "mask.png");
 
         Mat source = imread(original_path1, IMREAD_COLOR);
         Mat mask = imread(original_path2, IMREAD_COLOR);
@@ -187,13 +186,13 @@ int main()
         colorChange(source, mask, result, 1.5, .5, .5);
 
         imshow("Output",result);
-        imwrite(folder + "cloned.png", result);
+        imwrite("cloned.png", result);
     }
     else if(num == 5)
     {
         string folder = "cloning/Illumination_Change/";
-        string original_path1 = folder + "source1.png";
-        string original_path2 = folder + "mask.png";
+        string original_path1 = samples::findFile(folder + "source1.png");
+        string original_path2 = samples::findFile(folder + "mask.png");
 
         Mat source = imread(original_path1, IMREAD_COLOR);
         Mat mask = imread(original_path2, IMREAD_COLOR);
@@ -214,13 +213,13 @@ int main()
         illuminationChange(source, mask, result, 0.2f, 0.4f);
 
         imshow("Output",result);
-        imwrite(folder + "cloned.png", result);
+        imwrite("cloned.png", result);
     }
     else if(num == 6)
     {
         string folder = "cloning/Texture_Flattening/";
-        string original_path1 = folder + "source1.png";
-        string original_path2 = folder + "mask.png";
+        string original_path1 = samples::findFile(folder + "source1.png");
+        string original_path2 = samples::findFile(folder + "mask.png");
 
         Mat source = imread(original_path1, IMREAD_COLOR);
         Mat mask = imread(original_path2, IMREAD_COLOR);
@@ -241,7 +240,12 @@ int main()
         textureFlattening(source, mask, result, 30, 45, 3);
 
         imshow("Output",result);
-        imwrite(folder + "cloned.png", result);
+        imwrite("cloned.png", result);
+    }
+    else
+    {
+        cerr << "Invalid selection: " << num << endl;
+        exit(1);
     }
     waitKey(0);
 }

samples/cpp/cloning_gui.cpp

@@ -30,14 +30,12 @@
 * Result: The cloned image will be displayed.
 */
 
-#include <signal.h>
 #include "opencv2/photo.hpp"
 #include "opencv2/imgproc.hpp"
 #include "opencv2/imgcodecs.hpp"
 #include "opencv2/highgui.hpp"
 #include "opencv2/core.hpp"
 #include <iostream>
-#include <stdlib.h>
 
 // we're NOT "using namespace std;" here, to avoid collisions between the beta variable and std::beta in c++17
 using std::cin;
@@ -320,9 +318,9 @@ int main()
         cout << "Enter Destination Image: ";
         cin >> dest;
 
-        img0 = imread(src);
+        img0 = imread(samples::findFile(src));
 
-        img2 = imread(dest);
+        img2 = imread(samples::findFile(dest));
 
         if(img0.empty())
         {
@@ -370,7 +368,7 @@ int main()
         cout << "Blue: ";
         cin >> blue;
 
-        img0 = imread(src);
+        img0 = imread(samples::findFile(src));
 
         if(img0.empty())
         {
@@ -400,7 +398,7 @@ int main()
         cout << "beta: ";
         cin >> beta;
 
-        img0 = imread(src);
+        img0 = imread(samples::findFile(src));
 
         if(img0.empty())
         {
@@ -433,7 +431,7 @@ int main()
         cout << "kernel_size: ";
         cin >> kernel_size;
 
-        img0 = imread(src);
+        img0 = imread(samples::findFile(src));
 
         if(img0.empty())
         {

samples/cpp/connected_components.cpp

@@ -35,14 +35,14 @@ static void on_trackbar(int, void*)
 
 int main( int argc, const char** argv )
 {
-    CommandLineParser parser(argc, argv, "{@image|../data/stuff.jpg|image for converting to a grayscale}");
+    CommandLineParser parser(argc, argv, "{@image|stuff.jpg|image for converting to a grayscale}");
     parser.about("\nThis program demonstrates connected components and use of the trackbar\n");
     parser.printMessage();
     cout << "\nThe image is converted to grayscale and displayed, another image has a trackbar\n"
             "that controls thresholding and thereby the extracted contours which are drawn in color\n";
 
     String inputImage = parser.get<string>(0);
-    img = imread(inputImage, IMREAD_GRAYSCALE);
+    img = imread(samples::findFile(inputImage), IMREAD_GRAYSCALE);
 
     if(img.empty())
     {

samples/cpp/create_mask.cpp

@@ -95,7 +95,7 @@ void mouseHandler(int event, int x, int y, int, void*)
 
 int main(int argc, char **argv)
 {
-    CommandLineParser parser(argc, argv, "{@input | ../data/lena.jpg | input image}");
+    CommandLineParser parser(argc, argv, "{@input | lena.jpg | input image}");
     parser.about("This program demonstrates using mouse events\n");
     parser.printMessage();
     cout << "\n\tleft mouse button - set a point to create mask shape\n"
@@ -103,13 +103,13 @@ int main(int argc, char **argv)
         "\tmiddle mouse button - reset\n";
     String input_image = parser.get<String>("@input");
 
-    src = imread(input_image);
+    src = imread(samples::findFile(input_image));
 
     if (src.empty())
-        {
+    {
         printf("Error opening image: %s\n", input_image.c_str());
         return 0;
-        }
+    }
 
     namedWindow("Source", WINDOW_AUTOSIZE);
     setMouseCallback("Source", mouseHandler, NULL);

samples/cpp/dbt_face_detection.cpp

@@ -49,7 +49,7 @@ int main(int , char** )
         return 1;
     }
 
-    std::string cascadeFrontalfilename = "../../data/lbpcascades/lbpcascade_frontalface.xml";
+    std::string cascadeFrontalfilename = samples::findFile("data/lbpcascades/lbpcascade_frontalface.xml");
     cv::Ptr<cv::CascadeClassifier> cascade = makePtr<cv::CascadeClassifier>(cascadeFrontalfilename);
     cv::Ptr<DetectionBasedTracker::IDetector> MainDetector = makePtr<CascadeDetectorAdapter>(cascade);
     if ( cascade->empty() )

samples/cpp/demhist.cpp

@@ -59,12 +59,12 @@ static void updateBrightnessContrast( int /*arg*/, void* )
 static void help()
 {
     std::cout << "\nThis program demonstrates the use of calcHist() -- histogram creation.\n"
-              << "Usage: \n" << "demhist [image_name -- Defaults to ../data/baboon.jpg]" << std::endl;
+              << "Usage: \n" << "demhist [image_name -- Defaults to baboon.jpg]" << std::endl;
 }
 
 const char* keys =
 {
-    "{help h||}{@image|../data/baboon.jpg|input image file}"
+    "{help h||}{@image|baboon.jpg|input image file}"
 };
 
 int main( int argc, const char** argv )
@@ -78,7 +78,7 @@ int main( int argc, const char** argv )
     string inputImage = parser.get<string>(0);
 
     // Load the source image. HighGUI use.
-    image = imread( inputImage, 0 );
+    image = imread(samples::findFile(inputImage), IMREAD_GRAYSCALE);
     if(image.empty())
     {
         std::cerr << "Cannot read image file: " << inputImage << std::endl;

samples/cpp/detect_blob.cpp

@@ -14,7 +14,7 @@ static void help()
 {
     cout << "\n This program demonstrates how to use BLOB to detect and filter region \n"
         "Usage: \n"
-        "  ./detect_blob <image1(../data/detect_blob.png as default)>\n"
+        "  ./detect_blob <image1(detect_blob.png as default)>\n"
         "Press a key when image window is active to change descriptor";
 }
 
@@ -70,20 +70,19 @@ static String Legende(SimpleBlobDetector::Params &pAct)
 
 int main(int argc, char *argv[])
 {
-    vector<String> fileName;
-    Mat img(600, 800, CV_8UC1);
-    cv::CommandLineParser parser(argc, argv, "{@input |../data/detect_blob.png| }{h help | | }");
+    String fileName;
+    cv::CommandLineParser parser(argc, argv, "{@input |detect_blob.png| }{h help | | }");
     if (parser.has("h"))
     {
         help();
         return 0;
     }
-    fileName.push_back(parser.get<string>("@input"));
-    img = imread(fileName[0], IMREAD_COLOR);
-    if (img.rows*img.cols <= 0)
+    fileName = parser.get<string>("@input");
+    Mat img = imread(samples::findFile(fileName), IMREAD_COLOR);
+    if (img.empty())
     {
-        cout << "Image " << fileName[0] << " is empty or cannot be found\n";
-        return(0);
+        cout << "Image " << fileName << " is empty or cannot be found\n";
+        return 1;
     }
 
     SimpleBlobDetector::Params pDefaultBLOB;
@@ -116,14 +115,17 @@ int main(int argc, char *argv[])
     vector< Vec3b >  palette;
     for (int i = 0; i<65536; i++)
     {
-        palette.push_back(Vec3b((uchar)rand(), (uchar)rand(), (uchar)rand()));
+        uchar c1 = (uchar)rand();
+        uchar c2 = (uchar)rand();
+        uchar c3 = (uchar)rand();
+        palette.push_back(Vec3b(c1, c2, c3));
     }
     help();
 
 
     // These descriptors are going to be detecting and computing BLOBS with 6 different params
     // Param for first BLOB detector we want all
-    typeDesc.push_back("BLOB");    // see http://docs.opencv.org/trunk/d0/d7a/classcv_1_1SimpleBlobDetector.html
+    typeDesc.push_back("BLOB");    // see http://docs.opencv.org/3.4/d0/d7a/classcv_1_1SimpleBlobDetector.html
     pBLOB.push_back(pDefaultBLOB);
     pBLOB.back().filterByArea = true;
     pBLOB.back().minArea = 1;
@@ -150,7 +152,7 @@ int main(int argc, char *argv[])
     pBLOB.back().filterByConvexity = true;
     pBLOB.back().minConvexity = 0.;
     pBLOB.back().maxConvexity = (float)0.9;
-    // Param for six BLOB detector we want blob with gravity center color equal to 0 bug #4321 must be fixed
+    // Param for six BLOB detector we want blob with gravity center color equal to 0
     typeDesc.push_back("BLOB");
     pBLOB.push_back(pDefaultBLOB);
     pBLOB.back().filterByColor = true;

samples/cpp/detect_mser.cpp

@@ -412,7 +412,7 @@ int main(int argc, char *argv[])
     string input = parser.get<string>("@input");
     if (!input.empty())
     {
-        imgOrig = imread(input, IMREAD_GRAYSCALE);
+        imgOrig = imread(samples::findFile(input), IMREAD_GRAYSCALE);
         blur(imgOrig, img, blurSize);
     }
     else

samples/cpp/dft.cpp

@@ -14,12 +14,12 @@ static void help()
     printf("\nThis program demonstrated the use of the discrete Fourier transform (dft)\n"
            "The dft of an image is taken and it's power spectrum is displayed.\n"
            "Usage:\n"
-            "./dft [image_name -- default ../data/lena.jpg]\n");
+            "./dft [image_name -- default lena.jpg]\n");
 }
 
 const char* keys =
 {
-    "{help h||}{@image|../data/lena.jpg|input image file}"
+    "{help h||}{@image|lena.jpg|input image file}"
 };
 
 int main(int argc, const char ** argv)
@@ -32,7 +32,7 @@ int main(int argc, const char ** argv)
         return 0;
     }
     string filename = parser.get<string>(0);
-    Mat img = imread(filename, IMREAD_GRAYSCALE);
+    Mat img = imread(samples::findFile(filename), IMREAD_GRAYSCALE);
     if( img.empty() )
     {
         help();

samples/cpp/distrans.cpp

@@ -91,7 +91,7 @@ static void help()
 {
     printf("\nProgram to demonstrate the use of the distance transform function between edge images.\n"
             "Usage:\n"
-            "./distrans [image_name -- default image is ../data/stuff.jpg]\n"
+            "./distrans [image_name -- default image is stuff.jpg]\n"
             "\nHot keys: \n"
             "\tESC - quit the program\n"
             "\tC - use C/Inf metric\n"
@@ -107,7 +107,7 @@ static void help()
 
 const char* keys =
 {
-    "{help h||}{@image |../data/stuff.jpg|input image file}"
+    "{help h||}{@image |stuff.jpg|input image file}"
 };
 
 int main( int argc, const char** argv )
@@ -117,7 +117,7 @@ int main( int argc, const char** argv )
     if (parser.has("help"))
         return 0;
     string filename = parser.get<string>(0);
-    gray = imread(filename, 0);
+    gray = imread(samples::findFile(filename), 0);
     if(gray.empty())
     {
         printf("Cannot read image file: %s\n", filename.c_str());

samples/cpp/edge.cpp

@@ -43,12 +43,12 @@ static void help()
 {
     printf("\nThis sample demonstrates Canny edge detection\n"
            "Call:\n"
-           "    /.edge [image_name -- Default is ../data/fruits.jpg]\n\n");
+           "    /.edge [image_name -- Default is fruits.jpg]\n\n");
 }
 
 const char* keys =
 {
-    "{help h||}{@image |../data/fruits.jpg|input image name}"
+    "{help h||}{@image |fruits.jpg|input image name}"
 };
 
 int main( int argc, const char** argv )
@@ -57,7 +57,7 @@ int main( int argc, const char** argv )
     CommandLineParser parser(argc, argv, keys);
     string filename = parser.get<string>(0);
 
-    image = imread(filename, IMREAD_COLOR);
+    image = imread(samples::findFile(filename), IMREAD_COLOR);
     if(image.empty())
     {
         printf("Cannot read image file: %s\n", filename.c_str());

samples/cpp/facedetect.cpp

@@ -18,7 +18,7 @@ static void help()
                "   [--try-flip]\n"
                "   [filename|camera_index]\n\n"
             "see facedetect.cmd for one call:\n"
-            "./facedetect --cascade=\"../../data/haarcascades/haarcascade_frontalface_alt.xml\" --nested-cascade=\"../../data/haarcascades/haarcascade_eye_tree_eyeglasses.xml\" --scale=1.3\n\n"
+            "./facedetect --cascade=\"data/haarcascades/haarcascade_frontalface_alt.xml\" --nested-cascade=\"data/haarcascades/haarcascade_eye_tree_eyeglasses.xml\" --scale=1.3\n\n"
             "During execution:\n\tHit any key to quit.\n"
             "\tUsing OpenCV version " << CV_VERSION << "\n" << endl;
 }
@@ -41,8 +41,8 @@ int main( int argc, const char** argv )
 
     cv::CommandLineParser parser(argc, argv,
         "{help h||}"
-        "{cascade|../../data/haarcascades/haarcascade_frontalface_alt.xml|}"
-        "{nested-cascade|../../data/haarcascades/haarcascade_eye_tree_eyeglasses.xml|}"
+        "{cascade|data/haarcascades/haarcascade_frontalface_alt.xml|}"
+        "{nested-cascade|data/haarcascades/haarcascade_eye_tree_eyeglasses.xml|}"
         "{scale|1|}{try-flip||}{@filename||}"
     );
     if (parser.has("help"))
@@ -62,9 +62,9 @@ int main( int argc, const char** argv )
         parser.printErrors();
         return 0;
     }
-    if ( !nestedCascade.load( nestedCascadeName ) )
+    if (!nestedCascade.load(samples::findFileOrKeep(nestedCascadeName)))
         cerr << "WARNING: Could not load classifier cascade for nested objects" << endl;
-    if( !cascade.load( cascadeName ) )
+    if (!cascade.load(samples::findFile(cascadeName)))
     {
         cerr << "ERROR: Could not load classifier cascade" << endl;
         help();
@@ -74,21 +74,31 @@ int main( int argc, const char** argv )
     {
         int camera = inputName.empty() ? 0 : inputName[0] - '0';
         if(!capture.open(camera))
-            cout << "Capture from camera #" <<  camera << " didn't work" << endl;
-    }
-    else if( inputName.size() )
-    {
-        image = imread( inputName, 1 );
-        if( image.empty() )
         {
-            if(!capture.open( inputName ))
+            cout << "Capture from camera #" <<  camera << " didn't work" << endl;
+            return 1;
+        }
+    }
+    else if (!inputName.empty())
+    {
+        image = imread(samples::findFileOrKeep(inputName), IMREAD_COLOR);
+        if (image.empty())
+        {
+            if (!capture.open(samples::findFileOrKeep(inputName)))
+            {
                 cout << "Could not read " << inputName << endl;
+                return 1;
+            }
         }
     }
     else
     {
-        image = imread( "../data/lena.jpg", 1 );
-        if(image.empty()) cout << "Couldn't read ../data/lena.jpg" << endl;
+        image = imread(samples::findFile("lena.jpg"), IMREAD_COLOR);
+        if (image.empty())
+        {
+            cout << "Couldn't read lena.jpg" << endl;
+            return 1;
+        }
     }
 
     if( capture.isOpened() )

samples/cpp/facial_features.cpp

@@ -32,14 +32,14 @@ string face_cascade_path, eye_cascade_path, nose_cascade_path, mouth_cascade_pat
 int main(int argc, char** argv)
 {
     cv::CommandLineParser parser(argc, argv,
-            "{eyes||}{nose||}{mouth||}{help h||}");
+            "{eyes||}{nose||}{mouth||}{help h||}{@image||}{@facexml||}");
     if (parser.has("help"))
     {
         help();
         return 0;
     }
-    input_image_path = parser.get<string>(0);
-    face_cascade_path = parser.get<string>(1);
+    input_image_path = parser.get<string>("@image");
+    face_cascade_path = parser.get<string>("@facexml");
     eye_cascade_path = parser.has("eyes") ? parser.get<string>("eyes") : "";
     nose_cascade_path = parser.has("nose") ? parser.get<string>("nose") : "";
     mouth_cascade_path = parser.has("mouth") ? parser.get<string>("mouth") : "";
@@ -50,7 +50,7 @@ int main(int argc, char** argv)
     }
     // Load image and cascade classifier files
     Mat image;
-    image = imread(input_image_path);
+    image = imread(samples::findFile(input_image_path));
 
     // Detect faces and facial features
     vector<Rect_<int> > faces;
@@ -92,15 +92,16 @@ static void help()
         " \nhttps://github.com/opencv/opencv/tree/3.4/data/haarcascades";
 
     cout << "\n\nThe classifiers for nose and mouth can be downloaded from : "
-        " \nhttps://github.com/opencv/opencv_contrib/tree/master/modules/face/data/cascades\n";
+        " \nhttps://github.com/opencv/opencv_contrib/tree/3.4/modules/face/data/cascades\n";
 }
 
 static void detectFaces(Mat& img, vector<Rect_<int> >& faces, string cascade_path)
 {
     CascadeClassifier face_cascade;
-    face_cascade.load(cascade_path);
+    face_cascade.load(samples::findFile(cascade_path));
 
-    face_cascade.detectMultiScale(img, faces, 1.15, 3, 0|CASCADE_SCALE_IMAGE, Size(30, 30));
+    if (!face_cascade.empty())
+        face_cascade.detectMultiScale(img, faces, 1.15, 3, 0|CASCADE_SCALE_IMAGE, Size(30, 30));
     return;
 }
 
@@ -186,26 +187,29 @@ static void detectFacialFeaures(Mat& img, const vector<Rect_<int> > faces, strin
 static void detectEyes(Mat& img, vector<Rect_<int> >& eyes, string cascade_path)
 {
     CascadeClassifier eyes_cascade;
-    eyes_cascade.load(cascade_path);
+    eyes_cascade.load(samples::findFile(cascade_path, !cascade_path.empty()));
 
-    eyes_cascade.detectMultiScale(img, eyes, 1.20, 5, 0|CASCADE_SCALE_IMAGE, Size(30, 30));
+    if (!eyes_cascade.empty())
+        eyes_cascade.detectMultiScale(img, eyes, 1.20, 5, 0|CASCADE_SCALE_IMAGE, Size(30, 30));
     return;
 }
 
 static void detectNose(Mat& img, vector<Rect_<int> >& nose, string cascade_path)
 {
     CascadeClassifier nose_cascade;
-    nose_cascade.load(cascade_path);
+    nose_cascade.load(samples::findFile(cascade_path, !cascade_path.empty()));
 
-    nose_cascade.detectMultiScale(img, nose, 1.20, 5, 0|CASCADE_SCALE_IMAGE, Size(30, 30));
+    if (!nose_cascade.empty())
+        nose_cascade.detectMultiScale(img, nose, 1.20, 5, 0|CASCADE_SCALE_IMAGE, Size(30, 30));
     return;
 }
 
 static void detectMouth(Mat& img, vector<Rect_<int> >& mouth, string cascade_path)
 {
     CascadeClassifier mouth_cascade;
-    mouth_cascade.load(cascade_path);
+    mouth_cascade.load(samples::findFile(cascade_path, !cascade_path.empty()));
 
-    mouth_cascade.detectMultiScale(img, mouth, 1.20, 5, 0|CASCADE_SCALE_IMAGE, Size(30, 30));
+    if (!mouth_cascade.empty())
+        mouth_cascade.detectMultiScale(img, mouth, 1.20, 5, 0|CASCADE_SCALE_IMAGE, Size(30, 30));
     return;
 }

samples/cpp/falsecolor.cpp

@@ -87,7 +87,7 @@ int main(int argc, char** argv)
     Mat img;
 
     if (argc > 1)
-        img = imread(argv[1], IMREAD_GRAYSCALE);
+        img = imread(samples::findFile(argv[1]), IMREAD_GRAYSCALE);
     else
         img = DrawMyImage(2,256);
 

samples/cpp/ffilldemo.cpp

@@ -12,7 +12,7 @@ static void help()
 {
     cout << "\nThis program demonstrated the floodFill() function\n"
             "Call:\n"
-            "./ffilldemo [image_name -- Default: ../data/fruits.jpg]\n" << endl;
+            "./ffilldemo [image_name -- Default: fruits.jpg]\n" << endl;
 
     cout << "Hot keys: \n"
             "\tESC - quit the program\n"
@@ -74,7 +74,7 @@ static void onMouse( int event, int x, int y, int, void* )
 int main( int argc, char** argv )
 {
     cv::CommandLineParser parser (argc, argv,
-        "{help h | | show help message}{@image|../data/fruits.jpg| input image}"
+        "{help h | | show help message}{@image|fruits.jpg| input image}"
     );
     if (parser.has("help"))
     {
@@ -82,7 +82,7 @@ int main( int argc, char** argv )
         return 0;
     }
     string filename = parser.get<string>("@image");
-    image0 = imread(filename, 1);
+    image0 = imread(samples::findFile(filename), 1);
 
     if( image0.empty() )
     {

samples/cpp/filestorage.cpp

@@ -92,8 +92,8 @@ int main(int ac, char** av)
     cout << "writing images\n";
     fs << "images" << "[";
 
-    fs << "image1.jpg" << "myfi.png" << "../data/baboon.jpg";
-    cout << "image1.jpg" << " myfi.png" << " ../data/baboon.jpg" << endl;
+    fs << "image1.jpg" << "myfi.png" << "baboon.jpg";
+    cout << "image1.jpg" << " myfi.png" << " baboon.jpg" << endl;
 
     fs << "]";
 

samples/cpp/fitellipse.cpp

@@ -171,7 +171,7 @@ static void help()
     "contours and approximate it by ellipses. Three methods are used to find the \n"
     "elliptical fits: fitEllipse, fitEllipseAMS and fitEllipseDirect.\n"
     "Call:\n"
-    "./fitellipse [image_name -- Default ../data/stuff.jpg]\n" << endl;
+    "./fitellipse [image_name -- Default ellipses.jpg]\n" << endl;
 }
 
 int sliderPos = 70;
@@ -192,14 +192,14 @@ int main( int argc, char** argv )
     fitEllipseAMSQ    = true;
     fitEllipseDirectQ = true;
 
-    cv::CommandLineParser parser(argc, argv,"{help h||}{@image|../data/ellipses.jpg|}");
+    cv::CommandLineParser parser(argc, argv,"{help h||}{@image|ellipses.jpg|}");
     if (parser.has("help"))
     {
         help();
         return 0;
     }
     string filename = parser.get<string>("@image");
-    image = imread(filename, 0);
+    image = imread(samples::findFile(filename), 0);
     if( image.empty() )
     {
         cout << "Couldn't open image " << filename << "\n";

samples/cpp/grabcut.cpp

@@ -276,7 +276,7 @@ static void on_mouse( int event, int x, int y, int flags, void* param )
 
 int main( int argc, char** argv )
 {
-    cv::CommandLineParser parser(argc, argv, "{@input| ../data/messi5.jpg |}");
+    cv::CommandLineParser parser(argc, argv, "{@input| messi5.jpg |}");
     help();
 
     string filename = parser.get<string>("@input");
@@ -285,7 +285,7 @@ int main( int argc, char** argv )
         cout << "\nDurn, empty filename" << endl;
         return 1;
     }
-    Mat image = imread( filename, 1 );
+    Mat image = imread(samples::findFile(filename), IMREAD_COLOR);
     if( image.empty() )
     {
         cout << "\n Durn, couldn't read image filename " << filename << endl;

samples/cpp/gstreamer_pipeline.cpp

@@ -266,6 +266,7 @@ int main(int argc, char *argv[])
         cout << "Unsupported mode: " << mode << endl;
         return -1;
     }
+    file_name = samples::findFile(file_name);
     cout << "Mode: " << mode << ", Backend: " << backend << ", File: " << file_name << ", Codec: " << codec << endl;
 
     TickMeter total;

samples/cpp/image.cpp

@@ -14,7 +14,7 @@ static void help()
     "It shows reading of images, converting to planes and merging back, color conversion\n"
     "and also iterating through pixels.\n"
     "Call:\n"
-    "./image [image-name Default: ../data/lena.jpg]\n" << endl;
+    "./image [image-name Default: lena.jpg]\n" << endl;
 }
 
 // enable/disable use of mixed API in the code below.
@@ -27,7 +27,7 @@ static void help()
 
 int main( int argc, char** argv )
 {
-    cv::CommandLineParser parser(argc, argv, "{help h | |}{@image|../data/lena.jpg|}");
+    cv::CommandLineParser parser(argc, argv, "{help h | |}{@image|lena.jpg|}");
     if (parser.has("help"))
     {
         help();
@@ -47,7 +47,7 @@ int main( int argc, char** argv )
     // is converted, while the data is shared)
     //! [iplimage]
 #else
-    Mat img = imread(imagename); // the newer cvLoadImage alternative, MATLAB-style function
+    Mat img = imread(samples::findFile(imagename)); // the newer cvLoadImage alternative, MATLAB-style function
     if(img.empty())
     {
         fprintf(stderr, "Can not load image %s\n", imagename.c_str());

samples/cpp/image_alignment.cpp

@@ -3,7 +3,7 @@
 * findTransformECC that implements the image alignment ECC algorithm
 *
 *
-* The demo loads an image (defaults to ../data/fruits.jpg) and it artificially creates
+* The demo loads an image (defaults to fruits.jpg) and it artificially creates
 * a template image based on the given motion type. When two images are given,
 * the first image is the input image and the second one defines the template image.
 * In the latter case, you can also parse the warp's initialization.
@@ -44,7 +44,7 @@ static void draw_warped_roi(Mat& image, const int width, const int height, Mat&
 
 
 const std::string keys =
-    "{@inputImage    | ../data/fruits.jpg | input image filename }"
+    "{@inputImage    | fruits.jpg    | input image filename }"
     "{@templateImage |               | template image filename (optional)}"
     "{@inputWarp     |               | input warp (matrix) filename (optional)}"
     "{n numOfIter    | 50            | ECC's iterations }"
@@ -65,10 +65,10 @@ static void help(void)
         " are given, the initialization of the warp by command line parsing is possible. "
         "If inputWarp is missing, the identity transformation initializes the algorithm. \n" << endl;
 
-    cout << "\nUsage example (one image): \n./ecc ../data/fruits.jpg -o=outWarp.ecc "
+    cout << "\nUsage example (one image): \n./image_alignment fruits.jpg -o=outWarp.ecc "
         "-m=euclidean -e=1e-6 -N=70 -v=1 \n" << endl;
 
-    cout << "\nUsage example (two images with initialization): \n./ecc yourInput.png yourTemplate.png "
+    cout << "\nUsage example (two images with initialization): \n./image_alignment yourInput.png yourTemplate.png "
         "yourInitialWarp.ecc -o=outWarp.ecc -m=homography -e=1e-6 -N=70 -v=1 -w=yourFinalImage.png \n" << endl;
 
 }
@@ -212,7 +212,7 @@ int main (const int argc, const char * argv[])
     else
         mode_temp = MOTION_HOMOGRAPHY;
 
-    Mat inputImage = imread(imgFile,0);
+    Mat inputImage = imread(samples::findFile(imgFile), IMREAD_GRAYSCALE);
     if (inputImage.empty())
     {
         cerr << "Unable to load the inputImage" <<  endl;
@@ -224,7 +224,7 @@ int main (const int argc, const char * argv[])
 
     if (tempImgFile!="") {
         inputImage.copyTo(target_image);
-        template_image = imread(tempImgFile,0);
+        template_image = imread(samples::findFile(tempImgFile), IMREAD_GRAYSCALE);
         if (template_image.empty()){
             cerr << "Unable to load the template image" << endl;
             return -1;

samples/cpp/inpaint.cpp

@@ -14,7 +14,7 @@ static void help()
             << "with surrounding image areas.\n"
             "Using OpenCV version %s\n" << CV_VERSION << "\n"
     "Usage:\n"
-        "./inpaint [image_name -- Default ../data/fruits.jpg]\n" << endl;
+        "./inpaint [image_name -- Default fruits.jpg]\n" << endl;
 
     cout << "Hot keys: \n"
         "\tESC - quit the program\n"
@@ -47,24 +47,24 @@ static void onMouse( int event, int x, int y, int flags, void* )
 
 int main( int argc, char** argv )
 {
-    cv::CommandLineParser parser(argc, argv, "{@image|../data/fruits.jpg|}");
+    cv::CommandLineParser parser(argc, argv, "{@image|fruits.jpg|}");
     help();
 
-    string filename = parser.get<string>("@image");
-    Mat img0 = imread(filename, -1);
+    string filename = samples::findFile(parser.get<string>("@image"));
+    Mat img0 = imread(filename, IMREAD_COLOR);
     if(img0.empty())
     {
         cout << "Couldn't open the image " << filename << ". Usage: inpaint <image_name>\n" << endl;
         return 0;
     }
 
-    namedWindow( "image", 1 );
+    namedWindow("image", WINDOW_AUTOSIZE);
 
     img = img0.clone();
     inpaintMask = Mat::zeros(img.size(), CV_8U);
 
     imshow("image", img);
-    setMouseCallback( "image", onMouse, 0 );
+    setMouseCallback( "image", onMouse, NULL);
 
     for(;;)
     {

samples/cpp/laplace.cpp

@@ -25,39 +25,46 @@ int smoothType = GAUSSIAN;
 
 int main( int argc, char** argv )
 {
-    VideoCapture cap;
     cv::CommandLineParser parser(argc, argv, "{ c | 0 | }{ p | | }");
     help();
 
-    if( parser.get<string>("c").size() == 1 && isdigit(parser.get<string>("c")[0]) )
+    VideoCapture cap;
+    string camera = parser.get<string>("c");
+    if (camera.size() == 1 && isdigit(camera[0]))
         cap.open(parser.get<int>("c"));
     else
-        cap.open(parser.get<string>("c"));
-    if( cap.isOpened() )
-        cout << "Video " << parser.get<string>("c") <<
-            ": width=" << cap.get(CAP_PROP_FRAME_WIDTH) <<
-            ", height=" << cap.get(CAP_PROP_FRAME_HEIGHT) <<
-            ", nframes=" << cap.get(CAP_PROP_FRAME_COUNT) << endl;
-    if( parser.has("p") )
+        cap.open(samples::findFileOrKeep(camera));
+    if (!cap.isOpened())
     {
-        int pos = parser.get<int>("p");
-        if (!parser.check())
-        {
-            parser.printErrors();
-            return -1;
-        }
-        cout << "seeking to frame #" << pos << endl;
-        cap.set(CAP_PROP_POS_FRAMES, pos);
+        cerr << "Can't open camera/video stream: " << camera << endl;
+        return 1;
     }
-
-    if( !cap.isOpened() )
+    cout << "Video " << parser.get<string>("c") <<
+        ": width=" << cap.get(CAP_PROP_FRAME_WIDTH) <<
+        ", height=" << cap.get(CAP_PROP_FRAME_HEIGHT) <<
+        ", nframes=" << cap.get(CAP_PROP_FRAME_COUNT) << endl;
+    int pos = 0;
+    if (parser.has("p"))
     {
-        cout << "Could not initialize capturing...\n";
+        pos = parser.get<int>("p");
+    }
+    if (!parser.check())
+    {
+        parser.printErrors();
         return -1;
     }
 
-    namedWindow( "Laplacian", 0 );
-    createTrackbar( "Sigma", "Laplacian", &sigma, 15, 0 );
+    if (pos != 0)
+    {
+        cout << "seeking to frame #" << pos << endl;
+        if (!cap.set(CAP_PROP_POS_FRAMES, pos))
+        {
+            cerr << "ERROR: seekeing is not supported" << endl;
+        }
+    }
+
+    namedWindow("Laplacian", WINDOW_AUTOSIZE);
+    createTrackbar("Sigma", "Laplacian", &sigma, 15, 0);
 
     Mat smoothed, laplace, result;
 

samples/cpp/letter_recog.cpp

@@ -520,13 +520,13 @@ int main( int argc, char *argv[] )
     string data_filename;
     int method = 0;
 
-    cv::CommandLineParser parser(argc, argv, "{data|../data/letter-recognition.data|}{save||}{load||}{boost||}"
+    cv::CommandLineParser parser(argc, argv, "{data|letter-recognition.data|}{save||}{load||}{boost||}"
             "{mlp||}{knn knearest||}{nbayes||}{svm||}");
-    data_filename = parser.get<string>("data");
+    data_filename = samples::findFile(parser.get<string>("data"));
     if (parser.has("save"))
         filename_to_save = parser.get<string>("save");
     if (parser.has("load"))
-        filename_to_load = parser.get<string>("load");
+        filename_to_load = samples::findFile(parser.get<string>("load"));
     if (parser.has("boost"))
         method = 1;
     else if (parser.has("mlp"))

samples/cpp/live_detect_qrcode.cpp

@@ -7,10 +7,10 @@
 using namespace std;
 using namespace cv;
 
-void getMatWithQRCodeContour(Mat &color_image, vector<Point> transform);
-void getMatWithFPS(Mat &color_image, double fps);
-int  liveQRCodeDetect();
-int  showImageQRCodeDetect(string in, string out);
+static void drawQRCodeContour(Mat &color_image, vector<Point> transform);
+static void drawFPS(Mat &color_image, double fps);
+static int  liveQRCodeDetect(const string& out_file);
+static int  imageQRCodeDetect(const string& in_file, const string& out_file);
 
 int main(int argc, char *argv[])
 {
@@ -28,7 +28,9 @@ int main(int argc, char *argv[])
     }
 
     string in_file_name  = cmd_parser.get<string>("in");    // input  path to image
-    string out_file_name = cmd_parser.get<string>("out");   // output path to image
+    string out_file_name;
+    if (cmd_parser.has("out"))
+        out_file_name = cmd_parser.get<string>("out");   // output path to image
 
     if (!cmd_parser.check())
     {
@@ -39,16 +41,16 @@ int main(int argc, char *argv[])
     int return_code = 0;
     if (in_file_name.empty())
     {
-        return_code = liveQRCodeDetect();
+        return_code = liveQRCodeDetect(out_file_name);
     }
     else
     {
-        return_code = showImageQRCodeDetect(in_file_name, out_file_name);
+        return_code = imageQRCodeDetect(samples::findFile(in_file_name), out_file_name);
     }
     return return_code;
 }
 
-void getMatWithQRCodeContour(Mat &color_image, vector<Point> transform)
+void drawQRCodeContour(Mat &color_image, vector<Point> transform)
 {
     if (!transform.empty())
     {
@@ -70,19 +72,19 @@ void getMatWithQRCodeContour(Mat &color_image, vector<Point> transform)
     }
 }
 
-void getMatWithFPS(Mat &color_image, double fps)
+void drawFPS(Mat &color_image, double fps)
 {
     ostringstream convert;
-    convert << cvRound(fps) << " FPS.";
+    convert << cvRound(fps) << " FPS (QR detection)";
     putText(color_image, convert.str(), Point(25, 25), FONT_HERSHEY_DUPLEX, 1, Scalar(0, 0, 255), 2);
 }
 
-int liveQRCodeDetect()
+int liveQRCodeDetect(const string& out_file)
 {
     VideoCapture cap(0);
     if(!cap.isOpened())
     {
-        cout << "Cannot open a camera" << '\n';
+        cout << "Cannot open a camera" << endl;
         return -4;
     }
 
@@ -94,7 +96,11 @@ int liveQRCodeDetect()
         string decode_info;
         vector<Point> transform;
         cap >> frame;
-        if(frame.empty()) { break; }
+        if (frame.empty())
+        {
+            cout << "End of video stream" << endl;
+            break;
+        }
         cvtColor(frame, src, COLOR_BGR2GRAY);
 
         total.start();
@@ -102,24 +108,30 @@ int liveQRCodeDetect()
         if (result_detection)
         {
             decode_info = qrcode.decode(src, transform, straight_barcode);
-            if (!decode_info.empty()) { cout << decode_info << '\n'; }
+            if (!decode_info.empty()) { cout << decode_info << endl; }
         }
         total.stop();
         double fps = 1 / total.getTimeSec();
         total.reset();
 
-        if (result_detection) { getMatWithQRCodeContour(frame, transform); }
-        getMatWithFPS(frame, fps);
+        if (result_detection) { drawQRCodeContour(frame, transform); }
+        drawFPS(frame, fps);
 
         imshow("Live QR code detector", frame);
-        if( waitKey(30) > 0 ) { break; }
+        char c = (char)waitKey(30);
+        if (c == 27)
+            break;
+        if (c == ' ' && !out_file.empty())
+            imwrite(out_file, frame); // TODO write original frame too
     }
     return 0;
 }
 
-int showImageQRCodeDetect(string in, string out)
+int imageQRCodeDetect(const string& in_file, const string& out_file)
 {
-    Mat src = imread(in, IMREAD_GRAYSCALE), straight_barcode;
+    Mat color_src = imread(in_file, IMREAD_COLOR), src;
+    cvtColor(color_src, src, COLOR_BGR2GRAY);
+    Mat straight_barcode;
     string decoded_info;
     vector<Point> transform;
     const int count_experiments = 10;
@@ -135,54 +147,40 @@ int showImageQRCodeDetect(string in, string out)
         total.stop();
         transform_time += total.getTimeSec();
         total.reset();
-        if (!result_detection) { break; }
+        if (!result_detection)
+            continue;
 
         total.start();
         decoded_info = qrcode.decode(src, transform, straight_barcode);
         total.stop();
         transform_time += total.getTimeSec();
         total.reset();
-        if (decoded_info.empty()) { break; }
-
     }
     double fps = count_experiments / transform_time;
-    if (!result_detection) { cout << "QR code not found\n"; return -2; }
-    if (decoded_info.empty()) { cout << "QR code cannot be decoded\n"; return -3; }
+    if (!result_detection)
+        cout << "QR code not found" << endl;
+    if (decoded_info.empty())
+        cout << "QR code cannot be decoded" << endl;
 
-    Mat color_src = imread(in);
-    getMatWithQRCodeContour(color_src, transform);
-    getMatWithFPS(color_src, fps);
+    drawQRCodeContour(color_src, transform);
+    drawFPS(color_src, fps);
+
+    cout << "Input  image file path: " << in_file  << endl;
+    cout << "Output image file path: " << out_file << endl;
+    cout << "Size: " << color_src.size() << endl;
+    cout << "FPS: " << fps << endl;
+    cout << "Decoded info: " << decoded_info << endl;
+
+    if (!out_file.empty())
+    {
+        imwrite(out_file, color_src);
+    }
 
     for(;;)
     {
         imshow("Detect QR code on image", color_src);
-        if( waitKey(30) > 0 ) { break; }
-    }
-
-    if (!out.empty())
-    {
-        getMatWithQRCodeContour(color_src, transform);
-        getMatWithFPS(color_src, fps);
-
-        cout << "Input  image file path: " << in  << '\n';
-        cout << "Output image file path: " << out << '\n';
-        cout << "Size: " << color_src.size() << '\n';
-        cout << "FPS: " << fps << '\n';
-        cout << "Decoded info: " << decoded_info << '\n';
-
-        vector<int> compression_params;
-        compression_params.push_back(IMWRITE_PNG_COMPRESSION);
-        compression_params.push_back(9);
-        try
-        {
-            imwrite(out, color_src, compression_params);
-        }
-        catch (const cv::Exception& ex)
-        {
-            cout << "Exception converting image to PNG format: ";
-            cout << ex.what() << '\n';
-            return -3;
-        }
+        if (waitKey(0) == 27)
+            break;
     }
     return 0;
 }

samples/cpp/logistic_regression.cpp

@@ -83,7 +83,7 @@ static float calculateAccuracyPercent(const Mat &original, const Mat &predicted)
 
 int main()
 {
-    const String filename = "../data/data01.xml";
+    const String filename = samples::findFile("data01.xml");
     cout << "**********************************************************************" << endl;
     cout << filename
          << " contains digits 0 and 1 of 20 samples each, collected on an Android device" << endl;

samples/cpp/lsd_lines.cpp

@@ -9,7 +9,7 @@ using namespace cv;
 int main(int argc, char** argv)
 {
     cv::CommandLineParser parser(argc, argv,
-                                 "{input   i|../data/building.jpg|input image}"
+                                 "{input   i|building.jpg|input image}"
                                  "{refine  r|false|if true use LSD_REFINE_STD method, if false use LSD_REFINE_NONE method}"
                                  "{canny   c|false|use Canny edge detector}"
                                  "{overlay o|false|show result on input image}"
@@ -23,7 +23,7 @@ int main(int argc, char** argv)
 
     parser.printMessage();
 
-    String filename = parser.get<String>("input");
+    String filename = samples::findFile(parser.get<String>("input"));
     bool useRefine = parser.get<bool>("refine");
     bool useCanny = parser.get<bool>("canny");
     bool overlay = parser.get<bool>("overlay");

samples/cpp/mask_tmpl.cpp

@@ -8,17 +8,27 @@ using namespace cv;
 int main( int argc, const char** argv )
 {
     CommandLineParser parser(argc, argv,
-        "{ i | ../data/lena_tmpl.jpg |image name }"
-        "{ t | ../data/tmpl.png |template name }"
-        "{ m | ../data/mask.png |mask name }"
+        "{ i | lena_tmpl.jpg |image name }"
+        "{ t | tmpl.png |template name }"
+        "{ m | mask.png |mask name }"
         "{ cm| 3 |comparison method }");
 
-    cout << "This program demonstrates the use of template matching with mask.\n\n";
+    cout << "This program demonstrates the use of template matching with mask." << endl
+         << endl
+         << "Available methods: https://docs.opencv.org/3.4/df/dfb/group__imgproc__object.html#ga3a7850640f1fe1f58fe91a2d7583695d" << endl
+         << "    TM_SQDIFF = " << (int)TM_SQDIFF << endl
+         << "    TM_SQDIFF_NORMED = " << (int)TM_SQDIFF_NORMED << endl
+         << "    TM_CCORR = " << (int)TM_CCORR << endl
+         << "    TM_CCORR_NORMED = " << (int)TM_CCORR_NORMED << endl
+         << "    TM_CCOEFF = " << (int)TM_CCOEFF << endl
+         << "    TM_CCOEFF_NORMED = " << (int)TM_CCOEFF_NORMED << endl
+         << endl;
+
     parser.printMessage();
 
-    string filename = parser.get<string>("i");
-    string tmplname = parser.get<string>("t");
-    string maskname = parser.get<string>("m");
+    string filename = samples::findFile(parser.get<string>("i"));
+    string tmplname = samples::findFile(parser.get<string>("t"));
+    string maskname = samples::findFile(parser.get<string>("m"));
     Mat img = imread(filename);
     Mat tmpl = imread(tmplname);
     Mat mask = imread(maskname);

samples/cpp/matchmethod_orb_akaze_brisk.cpp

@@ -12,7 +12,7 @@ static void help()
 {
     cout << "\n This program demonstrates how to detect compute and match ORB BRISK and AKAZE descriptors \n"
         "Usage: \n"
-        "  ./matchmethod_orb_akaze_brisk --image1=<image1(../data/basketball1.png as default)> --image2=<image2(../data/basketball2.png as default)>\n"
+        "  ./matchmethod_orb_akaze_brisk --image1=<image1(basketball1.png as default)> --image2=<image2(basketball2.png as default)>\n"
         "Press a key when image window is active to change algorithm or descriptor";
 }
 
@@ -28,34 +28,34 @@ int main(int argc, char *argv[])
     typeDesc.push_back("AKAZE");    // see http://docs.opencv.org/trunk/d8/d30/classcv_1_1AKAZE.html
     typeDesc.push_back("ORB");      // see http://docs.opencv.org/trunk/de/dbf/classcv_1_1BRISK.html
     typeDesc.push_back("BRISK");    // see http://docs.opencv.org/trunk/db/d95/classcv_1_1ORB.html
-   // This algorithm would be used to match descriptors see http://docs.opencv.org/trunk/db/d39/classcv_1_1DescriptorMatcher.html#ab5dc5036569ecc8d47565007fa518257
+    // This algorithm would be used to match descriptors see http://docs.opencv.org/trunk/db/d39/classcv_1_1DescriptorMatcher.html#ab5dc5036569ecc8d47565007fa518257
     typeAlgoMatch.push_back("BruteForce");
     typeAlgoMatch.push_back("BruteForce-L1");
     typeAlgoMatch.push_back("BruteForce-Hamming");
     typeAlgoMatch.push_back("BruteForce-Hamming(2)");
     cv::CommandLineParser parser(argc, argv,
-        "{ @image1 | ../data/basketball1.png | }"
-        "{ @image2 | ../data/basketball2.png | }"
+        "{ @image1 | basketball1.png | }"
+        "{ @image2 | basketball2.png | }"
         "{help h ||}");
     if (parser.has("help"))
     {
         help();
         return 0;
     }
-    fileName.push_back(parser.get<string>(0));
-    fileName.push_back(parser.get<string>(1));
+    fileName.push_back(samples::findFile(parser.get<string>(0)));
+    fileName.push_back(samples::findFile(parser.get<string>(1)));
     Mat img1 = imread(fileName[0], IMREAD_GRAYSCALE);
     Mat img2 = imread(fileName[1], IMREAD_GRAYSCALE);
-    if (img1.rows*img1.cols <= 0)
-        {
-        cout << "Image " << fileName[0] << " is empty or cannot be found\n";
-        return(0);
-        }
-    if (img2.rows*img2.cols <= 0)
-        {
-        cout << "Image " << fileName[1] << " is empty or cannot be found\n";
-        return(0);
-        }
+    if (img1.empty())
+    {
+        cerr << "Image " << fileName[0] << " is empty or cannot be found" << endl;
+        return 1;
+    }
+    if (img2.empty())
+    {
+        cerr << "Image " << fileName[1] << " is empty or cannot be found" << endl;
+        return 1;
+    }
 
     vector<double> desMethCmp;
     Ptr<Feature2D> b;
@@ -74,10 +74,10 @@ int main(int argc, char *argv[])
         vector<String>::iterator itMatcher = typeAlgoMatch.end();
         if (*itDesc == "AKAZE-DESCRIPTOR_KAZE_UPRIGHT"){
             b = AKAZE::create(AKAZE::DESCRIPTOR_KAZE_UPRIGHT);
-            }
+        }
         if (*itDesc == "AKAZE"){
             b = AKAZE::create();
-            }
+        }
         if (*itDesc == "ORB"){
             b = ORB::create();
         }
@@ -157,12 +157,12 @@ int main(int argc, char *argv[])
         }
         catch (const Exception& e)
         {
+            cerr << "Exception: " << e.what() << endl;
             cout << "Feature : " << *itDesc << "\n";
             if (itMatcher != typeAlgoMatch.end())
             {
                 cout << "Matcher : " << *itMatcher << "\n";
             }
-            cout << e.msg << endl;
         }
     }
     int i=0;

samples/cpp/minarea.cpp

@@ -18,7 +18,7 @@ int main( int /*argc*/, char** /*argv*/ )
 {
     help();
 
-    Mat img(500, 500, CV_8UC3);
+    Mat img(500, 500, CV_8UC3, Scalar::all(0));
     RNG& rng = theRNG();
 
     for(;;)

samples/cpp/morphology2.cpp

@@ -33,8 +33,8 @@ int erode_dilate_pos = 0;
 // callback function for open/close trackbar
 static void OpenClose(int, void*)
 {
-    int n = open_close_pos - max_iters;
-    int an = n > 0 ? n : -n;
+    int n = open_close_pos;
+    int an = abs(n);
     Mat element = getStructuringElement(element_shape, Size(an*2+1, an*2+1), Point(an, an) );
     if( n < 0 )
         morphologyEx(src, dst, MORPH_OPEN, element);
@@ -46,8 +46,8 @@ static void OpenClose(int, void*)
 // callback function for erode/dilate trackbar
 static void ErodeDilate(int, void*)
 {
-    int n = erode_dilate_pos - max_iters;
-    int an = n > 0 ? n : -n;
+    int n = erode_dilate_pos;
+    int an = abs(n);
     Mat element = getStructuringElement(element_shape, Size(an*2+1, an*2+1), Point(an, an) );
     if( n < 0 )
         erode(src, dst, element);
@@ -59,13 +59,13 @@ static void ErodeDilate(int, void*)
 
 int main( int argc, char** argv )
 {
-    cv::CommandLineParser parser(argc, argv, "{help h||}{ @image | ../data/baboon.jpg | }");
+    cv::CommandLineParser parser(argc, argv, "{help h||}{ @image | baboon.jpg | }");
     if (parser.has("help"))
     {
         help();
         return 0;
     }
-    std::string filename = parser.get<std::string>("@image");
+    std::string filename = samples::findFile(parser.get<std::string>("@image"));
     if( (src = imread(filename,IMREAD_COLOR)).empty() )
     {
         help();
@@ -78,7 +78,14 @@ int main( int argc, char** argv )
 
     open_close_pos = erode_dilate_pos = max_iters;
     createTrackbar("iterations", "Open/Close",&open_close_pos,max_iters*2+1,OpenClose);
+    setTrackbarMin("iterations", "Open/Close", -max_iters);
+    setTrackbarMax("iterations", "Open/Close", max_iters);
+    setTrackbarPos("iterations", "Open/Close", 0);
+
     createTrackbar("iterations", "Erode/Dilate",&erode_dilate_pos,max_iters*2+1,ErodeDilate);
+    setTrackbarMin("iterations", "Erode/Dilate", -max_iters);
+    setTrackbarMax("iterations", "Erode/Dilate", max_iters);
+    setTrackbarPos("iterations", "Erode/Dilate", 0);
 
     for(;;)
     {

samples/cpp/npr_demo.cpp

@@ -28,26 +28,22 @@ using namespace cv;
 
 int main(int argc, char* argv[])
 {
-    cv::CommandLineParser parser(argc, argv, "{help h||show help message}{@image|../data/lena.jpg|input image}");
+    cv::CommandLineParser parser(argc, argv, "{help h||show help message}{@image|lena.jpg|input image}");
     if (parser.has("help"))
     {
         parser.printMessage();
-        exit(0);
-    }
-    if (parser.get<string>("@image").empty())
-    {
-        parser.printMessage();
-        exit(0);
+        return 0;
     }
+    string filename = samples::findFile(parser.get<string>("@image"));
 
-    Mat I = imread(parser.get<string>("@image"));
+    Mat I = imread(filename);
 
     int num,type;
 
     if(I.empty())
     {
         cout <<  "Image not found" << endl;
-        exit(0);
+        return 1;
     }
 
     cout << endl;

samples/cpp/peopledetect.cpp

@@ -72,7 +72,10 @@ int main(int argc, char** argv)
     if (file.empty())
         cap.open(camera);
     else
-        cap.open(file.c_str());
+    {
+        file = samples::findFileOrKeep(file);
+        cap.open(file);
+    }
     if (!cap.isOpened())
     {
         cout << "Can not open video stream: '" << (file.empty() ? "<camera>" : file) << "'" << endl;

samples/cpp/points_classifier.cpp

@@ -2,11 +2,6 @@
 #include "opencv2/imgproc.hpp"
 #include "opencv2/ml.hpp"
 #include "opencv2/highgui.hpp"
-#ifdef HAVE_OPENCV_OCL
-#define _OCL_KNN_ 1 // select whether using ocl::KNN method or not, default is using
-#define _OCL_SVM_ 1 // select whether using ocl::svm method or not, default is using
-#include "opencv2/ocl/ocl.hpp"
-#endif
 
 #include <stdio.h>
 

samples/cpp/polar_transforms.cpp

@@ -24,7 +24,7 @@ int main( int argc, char** argv )
     if( arg.size() == 1 && isdigit(arg[0]) )
         capture.open( arg[0] - '0' );
     else
-        capture.open( arg.c_str() );
+        capture.open(samples::findFileOrKeep(arg));
 
     if( !capture.isOpened() )
     {

samples/cpp/segment_objects.cpp

@@ -73,7 +73,7 @@ int main(int argc, char** argv)
     if (input.empty())
         cap.open(0);
     else
-        cap.open(input);
+        cap.open(samples::findFileOrKeep(input));
 
     if( !cap.isOpened() )
     {

samples/cpp/select3dobj.cpp

@@ -416,7 +416,7 @@ int main(int argc, char** argv)
     if ( parser.get<string>("@input").size() == 1 && isdigit(parser.get<string>("@input")[0]) )
         cameraId = parser.get<int>("@input");
     else
-        inputName = parser.get<string>("@input");
+        inputName = samples::findFileOrKeep(parser.get<string>("@input"));
     if (!parser.check())
     {
         puts(help);

samples/cpp/smiledetect.cpp

@@ -16,7 +16,7 @@ static void help()
             "   [--try-flip]\n"
             "   [video_filename|camera_index]\n\n"
             "Example:\n"
-            "./smiledetect --cascade=\"../../data/haarcascades/haarcascade_frontalface_alt.xml\" --smile-cascade=\"../../data/haarcascades/haarcascade_smile.xml\" --scale=2.0\n\n"
+            "./smiledetect --cascade=\"data/haarcascades/haarcascade_frontalface_alt.xml\" --smile-cascade=\"data/haarcascades/haarcascade_smile.xml\" --scale=2.0\n\n"
             "During execution:\n\tHit any key to quit.\n"
             "\tUsing OpenCV version " << CV_VERSION << "\n" << endl;
 }
@@ -41,16 +41,16 @@ int main( int argc, const char** argv )
     double scale;
     cv::CommandLineParser parser(argc, argv,
         "{help h||}{scale|1|}"
-        "{cascade|../../data/haarcascades/haarcascade_frontalface_alt.xml|}"
-        "{smile-cascade|../../data/haarcascades/haarcascade_smile.xml|}"
+        "{cascade|data/haarcascades/haarcascade_frontalface_alt.xml|}"
+        "{smile-cascade|data/haarcascades/haarcascade_smile.xml|}"
         "{try-flip||}{@input||}");
     if (parser.has("help"))
     {
         help();
         return 0;
     }
-    cascadeName = parser.get<string>("cascade");
-    nestedCascadeName = parser.get<string>("smile-cascade");
+    cascadeName = samples::findFile(parser.get<string>("cascade"));
+    nestedCascadeName = samples::findFile(parser.get<string>("smile-cascade"));
     tryflip = parser.has("try-flip");
     inputName = parser.get<string>("@input");
     scale = parser.get<int>("scale");
@@ -81,6 +81,7 @@ int main( int argc, const char** argv )
     }
     else if( inputName.size() )
     {
+        inputName = samples::findFileOrKeep(inputName);
         if(!capture.open( inputName ))
             cout << "Could not read " << inputName << endl;
     }

samples/cpp/squares.cpp

@@ -138,8 +138,8 @@ static void drawSquares( Mat& image, const vector<vector<Point> >& squares )
 
 int main(int argc, char** argv)
 {
-    static const char* names[] = { "../data/pic1.png", "../data/pic2.png", "../data/pic3.png",
-        "../data/pic4.png", "../data/pic5.png", "../data/pic6.png", 0 };
+    static const char* names[] = { "data/pic1.png", "data/pic2.png", "data/pic3.png",
+        "data/pic4.png", "data/pic5.png", "data/pic6.png", 0 };
     help(argv[0]);
 
     if( argc > 1)
@@ -152,10 +152,11 @@ int main(int argc, char** argv)
 
     for( int i = 0; names[i] != 0; i++ )
     {
-        Mat image = imread(names[i], IMREAD_COLOR);
+        string filename = samples::findFile(names[i]);
+        Mat image = imread(filename, IMREAD_COLOR);
         if( image.empty() )
         {
-            cout << "Couldn't load " << names[i] << endl;
+            cout << "Couldn't load " << filename << endl;
             continue;
         }
 

samples/cpp/stereo_calib.cpp

@@ -18,7 +18,6 @@
      Homepage:      http://opencv.org
      Online docs:   http://docs.opencv.org
      Q&A forum:     http://answers.opencv.org
-     Issue tracker: http://code.opencv.org
      GitHub:        https://github.com/opencv/opencv/
    ************************************************** */
 
@@ -46,11 +45,11 @@ static int print_help()
             " on the chessboards, and a flag: useCalibrated for \n"
             "   calibrated (0) or\n"
             "   uncalibrated \n"
-            "     (1: use cvStereoCalibrate(), 2: compute fundamental\n"
+            "     (1: use stereoCalibrate(), 2: compute fundamental\n"
             "         matrix separately) stereo. \n"
             " Calibrate the cameras and display the\n"
             " rectified results along with the computed disparity images.   \n" << endl;
-    cout << "Usage:\n ./stereo_calib -w=<board_width default=9> -h=<board_height default=6> -s=<square_size default=1.0> <image list XML/YML file default=../data/stereo_calib.xml>\n" << endl;
+    cout << "Usage:\n ./stereo_calib -w=<board_width default=9> -h=<board_height default=6> -s=<square_size default=1.0> <image list XML/YML file default=stereo_calib.xml>\n" << endl;
     return 0;
 }
 
@@ -347,11 +346,11 @@ int main(int argc, char** argv)
     Size boardSize;
     string imagelistfn;
     bool showRectified;
-    cv::CommandLineParser parser(argc, argv, "{w|9|}{h|6|}{s|1.0|}{nr||}{help||}{@input|../data/stereo_calib.xml|}");
+    cv::CommandLineParser parser(argc, argv, "{w|9|}{h|6|}{s|1.0|}{nr||}{help||}{@input|stereo_calib.xml|}");
     if (parser.has("help"))
         return print_help();
     showRectified = !parser.has("nr");
-    imagelistfn = parser.get<string>("@input");
+    imagelistfn = samples::findFile(parser.get<string>("@input"));
     boardSize.width = parser.get<int>("w");
     boardSize.height = parser.get<int>("h");
     float squareSize = parser.get<float>("s");

samples/cpp/stereo_match.cpp

@@ -65,8 +65,8 @@ int main(int argc, char** argv)
         print_help();
         return 0;
     }
-    img1_filename = parser.get<std::string>(0);
-    img2_filename = parser.get<std::string>(1);
+    img1_filename = samples::findFile(parser.get<std::string>(0));
+    img2_filename = samples::findFile(parser.get<std::string>(1));
     if (parser.has("algorithm"))
     {
         std::string _alg = parser.get<std::string>("algorithm");

samples/cpp/stitching.cpp

@@ -112,7 +112,7 @@ int parseCmdArgs(int argc, char** argv)
         }
         else
         {
-            Mat img = imread(argv[i]);
+            Mat img = imread(samples::findFile(argv[i]));
             if (img.empty())
             {
                 cout << "Can't read image '" << argv[i] << "'\n";

samples/cpp/stitching_detailed.cpp

@@ -405,7 +405,7 @@ int main(int argc, char* argv[])
 
     for (int i = 0; i < num_images; ++i)
     {
-        full_img = imread(img_names[i]);
+        full_img = imread(samples::findFile(img_names[i]));
         full_img_sizes[i] = full_img.size();
 
         if (full_img.empty())
@@ -727,7 +727,7 @@ int main(int argc, char* argv[])
         LOGLN("Compositing image #" << indices[img_idx]+1);
 
         // Read image and resize it if necessary
-        full_img = imread(img_names[img_idx]);
+        full_img = imread(samples::findFile(img_names[img_idx]));
         if (!is_compose_scale_set)
         {
             if (compose_megapix > 0)

samples/cpp/tutorial_code/calib3d/real_time_pose_estimation/src/main_detection.cpp

@@ -2,7 +2,7 @@
 #include <iostream>
 #include <time.h>
 // OpenCV
-#include <opencv2//core.hpp>
+#include <opencv2/core.hpp>
 #include <opencv2/core/utility.hpp>
 #include <opencv2/highgui.hpp>
 #include <opencv2/imgproc.hpp>

samples/cpp/tvl1_optical_flow.cpp

@@ -164,8 +164,8 @@ int main(int argc, const char* argv[])
         return -1;
     }
 
-    Mat frame0 = imread(frame0_name, IMREAD_GRAYSCALE);
-    Mat frame1 = imread(frame1_name, IMREAD_GRAYSCALE);
+    Mat frame0 = imread(samples::findFile(frame0_name), IMREAD_GRAYSCALE);
+    Mat frame1 = imread(samples::findFile(frame1_name), IMREAD_GRAYSCALE);
 
     if (frame0.empty())
     {

samples/cpp/warpPerspective_demo.cpp

@@ -20,7 +20,7 @@ static void help(char** argv)
     cout << "\nThis is a demo program shows how perspective transformation applied on an image, \n"
          "Using OpenCV version " << CV_VERSION << endl;
 
-    cout << "\nUsage:\n" << argv[0] << " [image_name -- Default ../data/right.jpg]\n" << endl;
+    cout << "\nUsage:\n" << argv[0] << " [image_name -- Default data/right.jpg]\n" << endl;
 
     cout << "\nHot keys: \n"
          "\tESC, q - quit the program\n"
@@ -45,9 +45,9 @@ bool validation_needed = true;
 int main(int argc, char** argv)
 {
     help(argv);
-    CommandLineParser parser(argc, argv, "{@input| ../data/right.jpg |}");
+    CommandLineParser parser(argc, argv, "{@input| data/right.jpg |}");
 
-    string filename = parser.get<string>("@input");
+    string filename = samples::findFile(parser.get<string>("@input"));
     Mat original_image = imread( filename );
     Mat image;
 

samples/cpp/watershed.cpp

@@ -13,7 +13,7 @@ static void help()
 {
     cout << "\nThis program demonstrates the famous watershed segmentation algorithm in OpenCV: watershed()\n"
             "Usage:\n"
-            "./watershed [image_name -- default is ../data/fruits.jpg]\n" << endl;
+            "./watershed [image_name -- default is fruits.jpg]\n" << endl;
 
 
     cout << "Hot keys: \n"
@@ -48,18 +48,18 @@ static void onMouse( int event, int x, int y, int flags, void* )
 
 int main( int argc, char** argv )
 {
-    cv::CommandLineParser parser(argc, argv, "{help h | | }{ @input | ../data/fruits.jpg | }");
+    cv::CommandLineParser parser(argc, argv, "{help h | | }{ @input | fruits.jpg | }");
     if (parser.has("help"))
     {
         help();
         return 0;
     }
-    string filename = parser.get<string>("@input");
+    string filename = samples::findFile(parser.get<string>("@input"));
     Mat img0 = imread(filename, 1), imgGray;
 
     if( img0.empty() )
     {
-        cout << "Couldn'g open image " << filename << ". Usage: watershed <image_name>\n";
+        cout << "Couldn't open image " << filename << ". Usage: watershed <image_name>\n";
         return 0;
     }
     help();

samples/data/calibration.yml

@@ -0,0 +1,15 @@
+%YAML:1.0
+images:
+  - left01.jpg
+  - left02.jpg
+  - left03.jpg
+  - left04.jpg
+  - left05.jpg
+  - left06.jpg
+  - left07.jpg
+  - left08.jpg
+  - left09.jpg
+  - left11.jpg
+  - left12.jpg
+  - left13.jpg
+  - left14.jpg

samples/dnn/colorization.cpp

@@ -64,9 +64,9 @@ int main(int argc, char **argv)
         parser.printMessage();
         return 0;
     }
-    string modelTxt = parser.get<string>("proto");
-    string modelBin = parser.get<string>("model");
-    string imageFile = parser.get<string>("image");
+    string modelTxt = samples::findFile(parser.get<string>("proto"));
+    string modelBin = samples::findFile(parser.get<string>("model"));
+    string imageFile = samples::findFile(parser.get<string>("image"));
     bool useOpenCL = parser.has("opencl");
     if (!parser.check())
     {

samples/dnn/common.py

@@ -86,6 +86,10 @@ def findFile(filename):
         if os.path.exists(filename):
             return filename
 
+        fpath = cv.samples.findFile(filename, False)
+        if fpath:
+            return fpath
+
         samplesDataDir = os.path.join(os.path.dirname(os.path.abspath(__file__)),
                                       '..',
                                       'data',

samples/dnn/edge_detection.py

@@ -43,7 +43,7 @@ cv.dnn_registerLayer('Crop', CropLayer)
 #! [Register]
 
 # Load the model.
-net = cv.dnn.readNet(args.prototxt, args.caffemodel)
+net = cv.dnn.readNet(cv.samples.findFile(args.prototxt), cv.samples.findFile(args.caffemodel))
 
 kWinName = 'Holistically-Nested Edge Detection'
 cv.namedWindow('Input', cv.WINDOW_NORMAL)

samples/dnn/fast_neural_style.py

@@ -13,7 +13,7 @@ parser.add_argument('--height', default=-1, type=int, help='Resize input to spec
 parser.add_argument('--median_filter', default=0, type=int, help='Kernel size of postprocessing blurring.')
 args = parser.parse_args()
 
-net = cv.dnn.readNetFromTorch(args.model)
+net = cv.dnn.readNetFromTorch(cv.samples.findFile(args.model))
 net.setPreferableBackend(cv.dnn.DNN_BACKEND_OPENCV);
 
 if args.input:

samples/dnn/mask_rcnn.py

@@ -68,13 +68,13 @@ def drawBox(frame, classId, conf, left, top, right, bottom):
 
 
 # Load a network
-net = cv.dnn.readNet(args.model, args.config)
+net = cv.dnn.readNet(cv.samples.findFile(args.model), cv.samples.findFile(args.config))
 net.setPreferableBackend(cv.dnn.DNN_BACKEND_OPENCV)
 
 winName = 'Mask-RCNN in OpenCV'
 cv.namedWindow(winName, cv.WINDOW_NORMAL)
 
-cap = cv.VideoCapture(args.input if args.input else 0)
+cap = cv.VideoCapture(cv.samples.findFileOrKeep(args.input) if args.input else 0)
 legend = None
 while cv.waitKey(1) < 0:
     hasFrame, frame = cap.read()

samples/dnn/mobilenet_ssd_accuracy.py

@@ -26,12 +26,12 @@ parser.add_argument('--annotations', help='Path to COCO annotations file.', requ
 args = parser.parse_args()
 
 ### Get OpenCV predictions #####################################################
-net = cv.dnn.readNetFromTensorflow(args.weights, args.prototxt)
+net = cv.dnn.readNetFromTensorflow(cv.samples.findFile(args.weights), cv.samples.findFile(args.prototxt))
 net.setPreferableBackend(cv.dnn.DNN_BACKEND_OPENCV);
 
 detections = []
 for imgName in os.listdir(args.images):
-    inp = cv.imread(os.path.join(args.images, imgName))
+    inp = cv.imread(cv.samples.findFile(os.path.join(args.images, imgName)))
     rows = inp.shape[0]
     cols = inp.shape[1]
     inp = cv.resize(inp, (300, 300))

samples/dnn/object_detection.py

@@ -67,7 +67,7 @@ if args.classes:
         classes = f.read().rstrip('\n').split('\n')
 
 # Load a network
-net = cv.dnn.readNet(args.model, args.config, args.framework)
+net = cv.dnn.readNet(cv.samples.findFile(args.model), cv.samples.findFile(args.config), args.framework)
 net.setPreferableBackend(args.backend)
 net.setPreferableTarget(args.target)
 outNames = net.getUnconnectedOutLayersNames()
@@ -182,7 +182,7 @@ def callback(pos):
 
 cv.createTrackbar('Confidence threshold, %', winName, int(confThreshold * 100), 99, callback)
 
-cap = cv.VideoCapture(args.input if args.input else 0)
+cap = cv.VideoCapture(cv.samples.findFileOrKeep(args.input) if args.input else 0)
 while cv.waitKey(1) < 0:
     hasFrame, frame = cap.read()
     if not hasFrame:

samples/dnn/openpose.cpp

@@ -66,9 +66,9 @@ int main(int argc, char **argv)
         "{ t threshold      |  0.1  | threshold or confidence value for the heatmap }"
     );
 
-    String modelTxt = parser.get<string>("proto");
-    String modelBin = parser.get<string>("model");
-    String imageFile = parser.get<String>("image");
+    String modelTxt = samples::findFile(parser.get<string>("proto"));
+    String modelBin = samples::findFile(parser.get<string>("model"));
+    String imageFile = samples::findFile(parser.get<String>("image"));
     int W_in = parser.get<int>("width");
     int H_in = parser.get<int>("height");
     float thresh = parser.get<float>("threshold");

samples/dnn/openpose.py

@@ -45,7 +45,7 @@ else:
 inWidth = args.width
 inHeight = args.height
 
-net = cv.dnn.readNetFromCaffe(args.proto, args.model)
+net = cv.dnn.readNetFromCaffe(cv.samples.findFile(args.proto), cv.samples.findFile(args.model))
 
 cap = cv.VideoCapture(args.input if args.input else 0)
 

samples/python/asift.py

@@ -116,11 +116,11 @@ if __name__ == '__main__':
     try:
         fn1, fn2 = args
     except:
-        fn1 = '../data/aero1.jpg'
-        fn2 = '../data/aero3.jpg'
+        fn1 = 'aero1.jpg'
+        fn2 = 'aero3.jpg'
 
-    img1 = cv.imread(fn1, 0)
-    img2 = cv.imread(fn2, 0)
+    img1 = cv.imread(cv.samples.findFile(fn1), cv.IMREAD_GRAYSCALE)
+    img2 = cv.imread(cv.samples.findFile(fn2), cv.IMREAD_GRAYSCALE)
     detector, matcher = init_feature(feature_name)
 
     if img1 is None:

samples/python/browse.py

@@ -32,7 +32,7 @@ if __name__ == '__main__':
     print()
 
     if len(sys.argv) > 1:
-        fn = sys.argv[1]
+        fn = cv.samples.findFile(sys.argv[1])
         print('loading %s ...' % fn)
         img = cv.imread(fn)
         if img is None:

samples/python/calibrate.py

@@ -53,7 +53,7 @@ if __name__ == '__main__':
 
     obj_points = []
     img_points = []
-    h, w = cv.imread(img_names[0], 0).shape[:2]  # TODO: use imquery call to retrieve results
+    h, w = cv.imread(img_names[0], cv.IMREAD_GRAYSCALE).shape[:2]  # TODO: use imquery call to retrieve results
 
     def processImage(fn):
         print('processing %s... ' % fn)

samples/python/camera_calibration_show_extrinsics.py

@@ -160,7 +160,7 @@ def draw_camera_boards(ax, camera_matrix, cam_width, cam_height, scale_focal,
 def main():
     parser = argparse.ArgumentParser(description='Plot camera calibration extrinsics.',
                                      formatter_class=argparse.ArgumentDefaultsHelpFormatter)
-    parser.add_argument('--calibration', type=str, default="../data/left_intrinsics.yml",
+    parser.add_argument('--calibration', type=str, default='left_intrinsics.yml',
                         help='YAML camera calibration file.')
     parser.add_argument('--cam_width', type=float, default=0.064/2,
                         help='Width/2 of the displayed camera.')
@@ -172,7 +172,7 @@ def main():
                         help='The calibration board is static and the camera is moving.')
     args = parser.parse_args()
 
-    fs = cv.FileStorage(args.calibration, cv.FILE_STORAGE_READ)
+    fs = cv.FileStorage(cv.samples.findFile(args.calibration), cv.FILE_STORAGE_READ)
     board_width = int(fs.getNode('board_width').real())
     board_height = int(fs.getNode('board_height').real())
     square_size = fs.getNode('square_size').real()

samples/python/coherence.py

@@ -51,9 +51,9 @@ if __name__ == '__main__':
     try:
         fn = sys.argv[1]
     except:
-        fn = '../data/baboon.jpg'
+        fn = 'baboon.jpg'
 
-    src = cv.imread(fn)
+    src = cv.imread(cv.samples.findFile(fn))
 
     def nothing(*argv):
         pass

samples/python/color_histogram.py

@@ -39,7 +39,7 @@ if __name__ == '__main__':
         fn = sys.argv[1]
     except:
         fn = 0
-    cam = video.create_capture(fn, fallback='synth:bg=../data/baboon.jpg:class=chess:noise=0.05')
+    cam = video.create_capture(fn, fallback='synth:bg=baboon.jpg:class=chess:noise=0.05')
 
     while True:
         flag, frame = cam.read()

samples/python/deconvolution.py

@@ -19,11 +19,11 @@ Usage:
     ESC   - exit
 
 Examples:
-  deconvolution.py --angle 135 --d 22  ../data/licenseplate_motion.jpg
+  deconvolution.py --angle 135 --d 22  licenseplate_motion.jpg
     (image source: http://www.topazlabs.com/infocus/_images/licenseplate_compare.jpg)
 
-  deconvolution.py --angle 86 --d 31  ../data/text_motion.jpg
-  deconvolution.py --circle --d 19  ../data/text_defocus.jpg
+  deconvolution.py --angle 86 --d 31  text_motion.jpg
+  deconvolution.py --circle --d 19  text_defocus.jpg
     (image source: compact digital photo camera, no artificial distortion)
 
 
@@ -73,11 +73,11 @@ if __name__ == '__main__':
     try:
         fn = args[0]
     except:
-        fn = '../data/licenseplate_motion.jpg'
+        fn = 'licenseplate_motion.jpg'
 
     win = 'deconvolution'
 
-    img = cv.imread(fn, 0)
+    img = cv.imread(cv.samples.findFile(fn), cv.IMREAD_GRAYSCALE)
     if img is None:
         print('Failed to load file:', fn)
         sys.exit(1)

samples/python/dft.py

@@ -38,8 +38,8 @@ def shift_dft(src, dst=None):
 
     h, w = src.shape[:2]
 
-    cx1 = cx2 = w/2
-    cy1 = cy2 = h/2
+    cx1 = cx2 = w // 2
+    cy1 = cy2 = h // 2
 
     # if the size is odd, then adjust the bottom/right quadrants
     if w % 2 != 0:
@@ -65,11 +65,13 @@ def shift_dft(src, dst=None):
 if __name__ == "__main__":
 
     if len(sys.argv) > 1:
-        im = cv.imread(sys.argv[1])
+        fname = sys.argv[1]
     else:
-        im = cv.imread('../data/baboon.jpg')
+        fname = 'baboon.jpg'
         print("usage : python dft.py <image_file>")
 
+    im = cv.imread(cv.samples.findFile(fname))
+
     # convert to grayscale
     im = cv.cvtColor(im, cv.COLOR_BGR2GRAY)
     h, w = im.shape[:2]

samples/python/digits.py

@@ -3,7 +3,7 @@
 '''
 SVM and KNearest digit recognition.
 
-Sample loads a dataset of handwritten digits from '../data/digits.png'.
+Sample loads a dataset of handwritten digits from 'digits.png'.
 Then it trains a SVM and KNearest classifiers on it and evaluates
 their accuracy.
 
@@ -42,7 +42,7 @@ from common import clock, mosaic
 
 SZ = 20 # size of each digit is SZ x SZ
 CLASS_N = 10
-DIGITS_FN = '../data/digits.png'
+DIGITS_FN = 'digits.png'
 
 def split2d(img, cell_size, flatten=True):
     h, w = img.shape[:2]
@@ -54,8 +54,9 @@ def split2d(img, cell_size, flatten=True):
     return cells
 
 def load_digits(fn):
+    fn = cv.samples.findFile(fn)
     print('loading "%s" ...' % fn)
-    digits_img = cv.imread(fn, 0)
+    digits_img = cv.imread(fn, cv.IMREAD_GRAYSCALE)
     digits = split2d(digits_img, (SZ, SZ))
     labels = np.repeat(np.arange(CLASS_N), len(digits)/CLASS_N)
     return digits, labels

samples/python/distrans.py

@@ -24,10 +24,11 @@ if __name__ == '__main__':
     try:
         fn = sys.argv[1]
     except:
-        fn = '../data/fruits.jpg'
+        fn = 'fruits.jpg'
     print(__doc__)
 
-    img = cv.imread(fn, 0)
+    fn = cv.samples.findFile(fn)
+    img = cv.imread(fn, cv.IMREAD_GRAYSCALE)
     if img is None:
         print('Failed to load fn:', fn)
         sys.exit(1)

samples/python/facedetect.py

@@ -40,13 +40,13 @@ if __name__ == '__main__':
     except:
         video_src = 0
     args = dict(args)
-    cascade_fn = args.get('--cascade', "../../data/haarcascades/haarcascade_frontalface_alt.xml")
-    nested_fn  = args.get('--nested-cascade', "../../data/haarcascades/haarcascade_eye.xml")
+    cascade_fn = args.get('--cascade', "data/haarcascades/haarcascade_frontalface_alt.xml")
+    nested_fn  = args.get('--nested-cascade', "data/haarcascades/haarcascade_eye.xml")
 
-    cascade = cv.CascadeClassifier(cascade_fn)
-    nested = cv.CascadeClassifier(nested_fn)
+    cascade = cv.CascadeClassifier(cv.samples.findFile(cascade_fn))
+    nested = cv.CascadeClassifier(cv.samples.findFile(nested_fn))
 
-    cam = create_capture(video_src, fallback='synth:bg=../data/lena.jpg:noise=0.05')
+    cam = create_capture(video_src, fallback='synth:bg={}:noise=0.05'.format(cv.samples.findFile('samples/data/lena.jpg')))
 
     while True:
         ret, img = cam.read()

samples/python/find_obj.py

@@ -147,11 +147,11 @@ if __name__ == '__main__':
     try:
         fn1, fn2 = args
     except:
-        fn1 = '../data/box.png'
-        fn2 = '../data/box_in_scene.png'
+        fn1 = 'box.png'
+        fn2 = 'box_in_scene.png'
 
-    img1 = cv.imread(fn1, 0)
-    img2 = cv.imread(fn2, 0)
+    img1 = cv.imread(cv.samples.findFile(fn1), cv.IMREAD_GRAYSCALE)
+    img2 = cv.imread(cv.samples.findFile(fn2), cv.IMREAD_GRAYSCALE)
     detector, matcher = init_feature(feature_name)
 
     if img1 is None:

samples/python/floodfill.py

@@ -25,10 +25,10 @@ if __name__ == '__main__':
     try:
         fn = sys.argv[1]
     except:
-        fn = '../data/fruits.jpg'
+        fn = 'fruits.jpg'
     print(__doc__)
 
-    img = cv.imread(fn, True)
+    img = cv.imread(cv.samples.findFile(fn))
     if img is None:
         print('Failed to load image file:', fn)
         sys.exit(1)

samples/python/gabor_threads.py

@@ -55,9 +55,9 @@ if __name__ == '__main__':
     try:
         img_fn = sys.argv[1]
     except:
-        img_fn = '../data/baboon.jpg'
+        img_fn = 'baboon.jpg'
 
-    img = cv.imread(img_fn)
+    img = cv.imread(cv.samples.findFile(img_fn))
     if img is None:
         print('Failed to load image file:', img_fn)
         sys.exit(1)

samples/python/grabcut.py

@@ -107,11 +107,11 @@ if __name__ == '__main__':
     if len(sys.argv) == 2:
         filename = sys.argv[1] # for drawing purposes
     else:
-        print("No input image given, so loading default image, ../data/lena.jpg \n")
+        print("No input image given, so loading default image, lena.jpg \n")
         print("Correct Usage: python grabcut.py <filename> \n")
-        filename = '../data/lena.jpg'
+        filename = 'lena.jpg'
 
-    img = cv.imread(filename)
+    img = cv.imread(cv.samples.findFile(filename))
     img2 = img.copy()                               # a copy of original image
     mask = np.zeros(img.shape[:2],dtype = np.uint8) # mask initialized to PR_BG
     output = np.zeros(img.shape,np.uint8)           # output image to be shown

samples/python/hist.py

@@ -60,10 +60,10 @@ if __name__ == '__main__':
     if len(sys.argv)>1:
         fname = sys.argv[1]
     else :
-        fname = '../data/lena.jpg'
+        fname = 'lena.jpg'
         print("usage : python hist.py <image_file>")
 
-    im = cv.imread(fname)
+    im = cv.imread(cv.samples.findFile(fname))
 
     if im is None:
         print('Failed to load image file:', fname)

samples/python/houghcircles.py

@@ -5,7 +5,7 @@ This example illustrates how to use cv.HoughCircles() function.
 
 Usage:
     houghcircles.py [<image_name>]
-    image argument defaults to ../data/board.jpg
+    image argument defaults to board.jpg
 '''
 
 # Python 2/3 compatibility
@@ -21,9 +21,9 @@ if __name__ == '__main__':
     try:
         fn = sys.argv[1]
     except IndexError:
-        fn = "../data/board.jpg"
+        fn = 'board.jpg'
 
-    src = cv.imread(fn, 1)
+    src = cv.imread(cv.samples.findFile(fn))
     img = cv.cvtColor(src, cv.COLOR_BGR2GRAY)
     img = cv.medianBlur(img, 5)
     cimg = src.copy() # numpy function

samples/python/houghlines.py

@@ -5,7 +5,7 @@ This example illustrates how to use Hough Transform to find lines
 
 Usage:
     houghlines.py [<image_name>]
-    image argument defaults to ../data/pic1.png
+    image argument defaults to pic1.png
 '''
 
 # Python 2/3 compatibility
@@ -22,9 +22,9 @@ if __name__ == '__main__':
     try:
         fn = sys.argv[1]
     except IndexError:
-        fn = "../data/pic1.png"
+        fn = 'pic1.png'
 
-    src = cv.imread(fn)
+    src = cv.imread(cv.samples.findFile(fn))
     dst = cv.Canny(src, 50, 200)
     cdst = cv.cvtColor(dst, cv.COLOR_GRAY2BGR)
 

samples/python/inpaint.py

@@ -27,11 +27,11 @@ if __name__ == '__main__':
     try:
         fn = sys.argv[1]
     except:
-        fn = '../data/fruits.jpg'
+        fn = 'fruits.jpg'
 
     print(__doc__)
 
-    img = cv.imread(fn)
+    img = cv.imread(cv.samples.findFile(fn))
     if img is None:
         print('Failed to load image file:', fn)
         sys.exit(1)

samples/python/letter_recog.py

@@ -158,10 +158,12 @@ if __name__ == '__main__':
     args, dummy = getopt.getopt(sys.argv[1:], '', ['model=', 'data=', 'load=', 'save='])
     args = dict(args)
     args.setdefault('--model', 'svm')
-    args.setdefault('--data', '../data/letter-recognition.data')
+    args.setdefault('--data', 'letter-recognition.data')
 
-    print('loading data %s ...' % args['--data'])
-    samples, responses = load_base(args['--data'])
+    datafile = cv.samples.findFile(args['--data'])
+
+    print('loading data %s ...' % datafile)
+    samples, responses = load_base(datafile)
     Model = models[args['--model']]
     model = Model()
 

samples/python/logpolar.py

@@ -22,9 +22,9 @@ if __name__ == '__main__':
     try:
         fn = sys.argv[1]
     except IndexError:
-        fn = '../data/fruits.jpg'
+        fn = 'fruits.jpg'
 
-    img = cv.imread(fn)
+    img = cv.imread(cv.samples.findFile(fn))
     if img is None:
         print('Failed to load image file:', fn)
         sys.exit(1)

samples/python/morphology.py

@@ -31,9 +31,9 @@ if __name__ == '__main__':
     try:
         fn = sys.argv[1]
     except:
-        fn = '../data/baboon.jpg'
+        fn = 'baboon.jpg'
 
-    img = cv.imread(fn)
+    img = cv.imread(cv.samples.findFile(fn))
 
     if img is None:
         print('Failed to load image file:', fn)

samples/python/peopledetect.py

@@ -40,7 +40,7 @@ if __name__ == '__main__':
     hog = cv.HOGDescriptor()
     hog.setSVMDetector( cv.HOGDescriptor_getDefaultPeopleDetector() )
 
-    default = ['../data/basketball2.png '] if len(sys.argv[1:]) == 0 else []
+    default = [cv.samples.findFile('basketball2.png')] if len(sys.argv[1:]) == 0 else []
 
     for fn in it.chain(*map(glob, default + sys.argv[1:])):
         print(fn, ' - ',)

samples/python/stereo_match.py

@@ -35,8 +35,8 @@ def write_ply(fn, verts, colors):
 
 if __name__ == '__main__':
     print('loading images...')
-    imgL = cv.pyrDown( cv.imread('../data/aloeL.jpg') )  # downscale images for faster processing
-    imgR = cv.pyrDown( cv.imread('../data/aloeR.jpg') )
+    imgL = cv.pyrDown(cv.imread(cv.samples.findFile('aloeL.jpg')))  # downscale images for faster processing
+    imgR = cv.pyrDown(cv.imread(cv.samples.findFile('aloeR.jpg')))
 
     # disparity range is tuned for 'aloe' image pair
     window_size = 3

samples/python/texture_flow.py

@@ -21,9 +21,9 @@ if __name__ == '__main__':
     try:
         fn = sys.argv[1]
     except:
-        fn = '../data/starry_night.jpg'
+        fn = 'starry_night.jpg'
 
-    img = cv.imread(fn)
+    img = cv.imread(cv.samples.findFile(fn))
     if img is None:
         print('Failed to load image file:', fn)
         sys.exit(1)

samples/python/tst_scene_render.py

@@ -98,8 +98,8 @@ class TestSceneRender():
 
 if __name__ == '__main__':
 
-    backGr = cv.imread('../data/graf1.png')
-    fgr = cv.imread('../data/box.png')
+    backGr = cv.imread(cv.samples.findFile('graf1.png'))
+    fgr = cv.imread(cv.samples.findFile('box.png'))
 
     render = TestSceneRender(backGr, fgr)
 

samples/python/tutorial_code/Histograms_Matching/histogram_calculation/calcHist_Demo.py

@@ -6,10 +6,10 @@ import argparse
 
 ## [Load image]
 parser = argparse.ArgumentParser(description='Code for Histogram Calculation tutorial.')
-parser.add_argument('--input', help='Path to input image.', default='../data/lena.jpg')
+parser.add_argument('--input', help='Path to input image.', default='lena.jpg')
 args = parser.parse_args()
 
-src = cv.imread(args.input)
+src = cv.imread(cv.samples.findFile(args.input))
 if src is None:
     print('Could not open or find the image:', args.input)
     exit(0)

samples/python/tutorial_code/Histograms_Matching/histogram_equalization/EqualizeHist_Demo.py

@@ -4,10 +4,10 @@ import argparse
 
 ## [Load image]
 parser = argparse.ArgumentParser(description='Code for Histogram Equalization tutorial.')
-parser.add_argument('--input', help='Path to input image.', default='../data/lena.jpg')
+parser.add_argument('--input', help='Path to input image.', default='lena.jpg')
 args = parser.parse_args()
 
-src = cv.imread(args.input)
+src = cv.imread(cv.samples.findFile(args.input))
 if src is None:
     print('Could not open or find the image:', args.input)
     exit(0)

samples/python/tutorial_code/ImgTrans/Filter2D/filter2D.py

@@ -11,15 +11,15 @@ def main(argv):
     window_name = 'filter2D Demo'
 
     ## [load]
-    imageName = argv[0] if len(argv) > 0 else "../data/lena.jpg"
+    imageName = argv[0] if len(argv) > 0 else 'lena.jpg'
 
     # Loads an image
-    src = cv.imread(imageName, cv.IMREAD_COLOR)
+    src = cv.imread(cv.samples.findFile(imageName), cv.IMREAD_COLOR)
 
     # Check if image is loaded fine
     if src is None:
         print ('Error opening image!')
-        print ('Usage: filter2D.py [image_name -- default ../data/lena.jpg] \n')
+        print ('Usage: filter2D.py [image_name -- default lena.jpg] \n')
         return -1
     ## [load]
     ## [init_arguments]

samples/python/tutorial_code/ImgTrans/HoughCircle/hough_circle.py

@@ -5,11 +5,11 @@ import numpy as np
 
 def main(argv):
     ## [load]
-    default_file =  "../../../../data/smarties.png"
+    default_file = 'smarties.png'
     filename = argv[0] if len(argv) > 0 else default_file
 
     # Loads an image
-    src = cv.imread(filename, cv.IMREAD_COLOR)
+    src = cv.imread(cv.samples.findFile(filename), cv.IMREAD_COLOR)
 
     # Check if image is loaded fine
     if src is None: