Adding two samples that deal with FileStorage - useful for creating image lists

samples/cpp/calibration.cpp

@@ -14,8 +14,10 @@ using namespace std;
    calibration  -w 4 -h 5 -s 0.025 -o camera.yml -op -oe
  
  example command line for calibration from a list of stored images:
+   imagelist_creator image_list.xml *.png
    calibration -w 4 -h 5 -s 0.025 -o camera.yml -op -oe image_list.xml
  where image_list.xml is the standard OpenCV XML/YAML
+ use imagelist_creator to create the xml or yaml list
  file consisting of the list of strings, e.g.:
  
 <?xml version="1.0"?>
@@ -273,6 +275,7 @@ int main( int argc, char** argv )
             "     [-su]                    # show undistorted images after calibration\n"
             "     [input_data]             # input data, one of the following:\n"
             "                              #  - text file with a list of the images of the board\n"
+            "                              #    the text file can be generated with imagelist_creator\n"
             "                              #  - name of video file with a video of the board\n"
             "                              # if input_data not specified, a live view from the camera is used\n"
             "\n" );

samples/cpp/filestorage_sample.cpp

@@ -0,0 +1,150 @@
+/*
+ * filestorage_sample demonstrate the usage of the opencv serialization functionality
+ */
+
+#include "opencv2/core/core.hpp"
+#include <iostream>
+#include <string>
+
+using std::string;
+using std::cout;
+using std::endl;
+using std::cerr;
+using std::ostream;
+using namespace cv;
+
+void help(char** av)
+{
+  cout << "usage:\n" << av[0] << " outputfile.yml.gz\n"
+      << "Try using different extensions.(e.g. yaml yml xml xml.gz etc...)\n"
+      << "This will serialize some matrices and image names to the format specified." << endl;
+}
+
+struct MyData
+{
+  MyData() :
+    A(0), X(0), id()
+  {
+  }
+  explicit MyData(int) :
+    A(97), X(CV_PI), id("mydata1234")
+  {
+  }
+  int A;
+  double X;
+  string id;
+  void write(FileStorage& fs) const
+  {
+    fs << "{" << "A" << A << "X" << X << "id" << id << "}";
+  }
+  void read(const FileNode& node)
+  {
+
+    A = (int)node["A"];
+    X = (double)node["X"];
+    id = (string)node["id"];
+  }
+};
+
+void write(FileStorage& fs, const std::string& name, const MyData& x){
+  x.write(fs);
+}
+void read(const FileNode& node, MyData& x, const MyData& default_value = MyData()){
+  if(node.empty())
+    x = default_value;
+  else
+    x = (MyData)node;
+}
+
+ostream& operator<<(ostream& out, const MyData& m){
+  out << "{ id = " << m.id << ", ";
+  out << "X = " << m.X << ", ";
+  out << "A = " << m.A << "}";
+  return out;
+}
+int main(int ac, char** av)
+{
+  if (ac != 2)
+  {
+    help(av);
+    return 1;
+  }
+
+  string filename = av[1];
+
+  //write
+  {
+    FileStorage fs(filename, FileStorage::WRITE);
+
+    cout << "writing images\n";
+    fs << "images" << "[";
+
+    fs << "image1.jpg" << "myfi.png" << "baboon.jpg";
+    cout << "image1.jpg" << " myfi.png" << " baboon.jpg" << endl;
+
+    fs << "]";
+
+    cout << "writing mats\n";
+    Mat R =Mat_<double>::eye(3, 3),T = Mat_<double>::zeros(3, 1);
+    cout << "R = " << R << "\n";
+    cout << "T = " << T << "\n";
+    fs << "R" << R;
+    fs << "T" << T;
+
+    cout << "writing MyData struct\n";
+    MyData m(1);
+    fs << "mdata" << m;
+    cout << m << endl;
+  }
+
+  //read
+  {
+    FileStorage fs(filename, FileStorage::READ);
+
+    if (!fs.isOpened())
+    {
+      cerr << "failed to open " << filename << endl;
+      help(av);
+      return 1;
+    }
+
+    FileNode n = fs["images"];
+    if (n.type() != FileNode::SEQ)
+    {
+      cerr << "images is not a sequence! FAIL" << endl;
+      return 1;
+    }
+
+    cout << "reading images\n";
+    FileNodeIterator it = n.begin(), it_end = n.end();
+    for (; it != it_end; ++it)
+    {
+      cout << (string)*it << "\n";
+    }
+
+    Mat R, T;
+    cout << "reading R and T" << endl;
+
+    fs["R"] >> R;
+    fs["T"] >> T;
+
+    cout << "R = " << R << "\n";
+    cout << "T = " << T << endl;
+
+    MyData m;
+    fs["mdata"] >> m;
+
+    cout << "read mdata\n";
+    cout << m << endl;
+
+    cout << "attempting to read mdata_b\n";
+    fs["mdata_b"] >> m;
+    cout << "read mdata_b\n";
+    cout << m << endl;
+
+  }
+
+  cout << "Try opening " << filename << " to see the serialized data." << endl;
+
+  return 0;
+}

samples/cpp/imagelist_creator.cpp

@@ -0,0 +1,38 @@
+/*this creates a yaml or xml list of files from the command line args
+ */
+
+#include "opencv2/core/core.hpp"
+#include <string>
+#include <iostream>
+
+using std::string;
+using std::cout;
+using std::endl;
+
+using namespace cv;
+
+void help(char** av)
+{
+  cout << "usage:\n" << av[0] << " imagelist.yaml *.png\n"
+      << "Try using different extensions.(e.g. yaml yml xml xml.gz etc...)\n"
+      << "This will serialize this list of images or whatever with opencv's FileStorage framework" << endl;
+}
+
+int main(int ac, char** av)
+{
+  if (ac < 3)
+  {
+    help(av);
+    return 1;
+  }
+
+  string outputname = av[1];
+
+  FileStorage fs(outputname, FileStorage::WRITE);
+  fs << "images" << "[";
+  for(int i = 2; i < ac; i++){
+    fs << string(av[i]);
+  }
+  fs << "]";
+  return 0;
+}