Merge pull request #25911 from asmorkalov:as/HAL_fast_GaussianBlur

Post-merge fixes for algorithm hint API

CMakeLists.txt

@@ -1261,7 +1261,7 @@ endif()
 if(DEFINED OPENCV_ALGO_HINT_DEFAULT)
   status("    Algorithm Hint:"  ${OPENCV_ALGO_HINT_DEFAULT})
 else()
-  status("    Algorithm Hint:" " ALGO_ACCURATE")
+  status("    Algorithm Hint:" " ALGO_HINT_ACCURATE")
 endif()
 
 # ========================= CPU code generation mode =========================

doc/tutorials/introduction/config_reference/config_reference.markdown

@@ -217,7 +217,7 @@ Following options can be used to produce special builds with instrumentation or
 | `ENABLE_BUILD_HARDENING` | GCC, Clang, MSVC | Enable compiler options which reduce possibility of code exploitation.  |
 | `ENABLE_LTO` | GCC, Clang, MSVC | Enable Link Time Optimization (LTO). |
 | `ENABLE_THIN_LTO` | Clang | Enable thin LTO which incorporates intermediate bitcode to binaries allowing consumers optimize their applications later. |
-| `OPENCV_ALGO_HINT_DEFAULT` | Any | Set default OpenCV implementation hint value: `ALGO_ACCURATE` or `ALGO_APROX`. Dangerous! The option  changes behaviour globally and may affect accuracy of many algorithms. |
+| `OPENCV_ALGO_HINT_DEFAULT` | Any | Set default OpenCV implementation hint value: `ALGO_HINT_ACCURATE` or `ALGO_HINT_APROX`. Dangerous! The option  changes behaviour globally and may affect accuracy of many algorithms. |
 
 @see [GCC instrumentation](https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html)
 @see [Build hardening](https://en.wikipedia.org/wiki/Hardening_(computing))

modules/core/include/opencv2/core.hpp

@@ -150,18 +150,6 @@ It is possible to alternate error processing by using #redirectError().
  */
 CV_EXPORTS CV_NORETURN void error(const Exception& exc);
 
-/*! @brief Flags that allow to midify some functions behavior. Used as set of flags.
-*/
-enum AlgorithmHint {
-    ALGO_DEFAULT = 0, //!< Default algorithm behaviour defined during OpenCV build
-    ALGO_ACCURATE = 1, //!< Use generic portable implementation
-    ALGO_APPROX = 2, //!< Allow alternative approximations to get faster implementation. Behaviour and result depends on a platform
-};
-
-/*! @brief Returns ImplementationHint selected by default, a.k.a. `IMPL_DEFAULT` defined during OpenCV compilation.
- */
-CV_EXPORTS_W AlgorithmHint getDefaultAlgorithmHint();
-
 enum SortFlags { SORT_EVERY_ROW    = 0, //!< each matrix row is sorted independently
                  SORT_EVERY_COLUMN = 1, //!< each matrix column is sorted
                                         //!< independently; this flag and the previous one are

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

@@ -544,6 +544,18 @@ bool isAligned(const void* p1, const void* p2, const void* p3, const void* p4)
     return isAligned<N>(((size_t)p1)|((size_t)p2)|((size_t)p3)|((size_t)p4));
 }
 
+/*! @brief Flags that allow to midify some functions behavior. Used as set of flags.
+*/
+enum AlgorithmHint {
+    ALGO_HINT_DEFAULT = 0, //!< Default algorithm behaviour defined during OpenCV build
+    ALGO_HINT_ACCURATE = 1, //!< Use generic portable implementation
+    ALGO_HINT_APPROX = 2, //!< Allow alternative approximations to get faster implementation. Behaviour and result depends on a platform
+};
+
+/*! @brief Returns AlgorithmHint defined during OpenCV compilation. Defines #ALGO_HINT_DEFAULT behavior.
+ */
+CV_EXPORTS_W AlgorithmHint getDefaultAlgorithmHint();
+
 /** @brief Enables or disables the optimized code.
 
 The function can be used to dynamically turn on and off optimized dispatched code (code that uses SSE4.2, AVX/AVX2,

modules/core/src/system.cpp

@@ -46,7 +46,6 @@
 #include <iostream>
 #include <ostream>
 
-#include <opencv2/core.hpp>
 #include <opencv2/core/utils/configuration.private.hpp>
 #include <opencv2/core/utils/trace.private.hpp>
 
@@ -2894,7 +2893,7 @@ AlgorithmHint getDefaultAlgorithmHint()
 #ifdef OPENCV_ALGO_HINT_DEFAULT
     return OPENCV_ALGO_HINT_DEFAULT;
 #else
-    return ALGO_ACCURATE;
+    return ALGO_HINT_ACCURATE;
 #endif
 };
 

modules/imgproc/include/opencv2/imgproc.hpp

@@ -1543,7 +1543,7 @@ sigmaX, and sigmaY.
 CV_EXPORTS_W void GaussianBlur( InputArray src, OutputArray dst, Size ksize,
                                 double sigmaX, double sigmaY = 0,
                                 int borderType = BORDER_DEFAULT,
-                                AlgorithmHint hint = cv::ALGO_DEFAULT );
+                                AlgorithmHint hint = cv::ALGO_HINT_DEFAULT );
 
 /** @brief Applies the bilateral filter to an image.
 

modules/imgproc/src/smooth.dispatch.cpp

@@ -612,7 +612,7 @@ void GaussianBlur(InputArray _src, OutputArray _dst, Size ksize,
 {
     CV_INSTRUMENT_REGION();
 
-    if (hint == cv::ALGO_DEFAULT)
+    if (hint == cv::ALGO_HINT_DEFAULT)
         hint = cv::getDefaultAlgorithmHint();
 
     CV_Assert(!_src.empty());
@@ -698,7 +698,7 @@ void GaussianBlur(InputArray _src, OutputArray _dst, Size ksize,
                          borderType & ~BORDER_ISOLATED);
             }
 
-            if (hint == ALGO_APPROX)
+            if (hint == ALGO_HINT_APPROX)
             {
                 Point ofs;
                 Size wsz(src.cols, src.rows);
@@ -768,7 +768,7 @@ void GaussianBlur(InputArray _src, OutputArray _dst, Size ksize,
                          ofs.x, ofs.y, wsz.width - src2.cols - ofs.x,  wsz.height - src2.rows - ofs.y, ksize.width, borderType&~BORDER_ISOLATED);
             }
 
-            if (hint == ALGO_APPROX)
+            if (hint == ALGO_HINT_APPROX)
             {
                 Point ofs;
                 Size wsz(src.cols, src.rows);

modules/imgproc/test/test_smooth_bitexact.cpp

@@ -288,21 +288,13 @@ TEST_P(GaussianBlurVsBitexact, approx)
     orig.convertTo(src, dtype);
 
     cv::Mat gt;
-    GaussianBlur(src, gt, Size(ksize, ksize), sigma, sigma, border, ALGO_ACCURATE);
+    GaussianBlur(src, gt, Size(ksize, ksize), sigma, sigma, border, ALGO_HINT_ACCURATE);
 
     cv::Mat dst;
-    GaussianBlur(src, dst, Size(ksize, ksize), sigma, sigma, border, ALGO_APPROX);
+    GaussianBlur(src, dst, Size(ksize, ksize), sigma, sigma, border, ALGO_HINT_APPROX);
 
-    cv::Mat diff;
+    EXPECT_LE(cvtest::norm(dst, gt, NORM_INF), 1);
-    cv::absdiff(dst, gt, diff);
+    EXPECT_LE(cvtest::norm(dst, gt, NORM_L1 | NORM_RELATIVE), 0.06); // Less 6% of different pixels
-    cv::Mat flatten_diff = diff.reshape(1, diff.rows);
-
-    int nz = countNonZero(flatten_diff);
-    EXPECT_LE(nz, 0.06*src.total()); // Less 6% of different pixels
-
-    double min_val, max_val;
-    minMaxLoc(flatten_diff, &min_val, &max_val);
-    EXPECT_LE(max_val, 2); // expectes results floating +-1
 }
 
 INSTANTIATE_TEST_CASE_P(/*nothing*/, GaussianBlurVsBitexact,