Adding chapter 13 examples

CMakeLists.txt

@@ -36,6 +36,8 @@ add_executable( example_11-02 example_11-02.cpp )
 add_executable( example_11-03 example_11-03.cpp )
 add_executable( example_12-01 example_12-01.cpp )
 add_executable( example_12-02 example_12-02.cpp )
+add_executable( example_13-01 example_13-01.cpp )
+add_executable( example_13-02 example_13-02.cpp )
 add_executable( example_16-01 example_16-01.cpp )
 
 target_link_libraries( example_02-01 ${OpenCV_LIBS} )
@@ -67,6 +69,8 @@ target_link_libraries( example_11-02 ${OpenCV_LIBS} )
 target_link_libraries( example_11-03 ${OpenCV_LIBS} )
 target_link_libraries( example_12-01 ${OpenCV_LIBS} )
 target_link_libraries( example_12-02 ${OpenCV_LIBS} )
+target_link_libraries( example_13-01 ${OpenCV_LIBS} )
+target_link_libraries( example_13-02 ${OpenCV_LIBS} )
 target_link_libraries( example_16-01 ${OpenCV_LIBS} )
 
 

example_13-01.cpp

@@ -0,0 +1,55 @@
+// Example 13-1. Histogram computation and display
+
+#include <opencv2/opencv.hpp>
+#include <iostream>
+
+using namespace std;
+
+int main( int argc, char** argv ){
+  if(argc != 2) {
+    cout << "Computer Color Histogram\nUsage: " <<argv[0] <<" <imagename>" << endl;
+    return -1;
+  }
+
+  cv::Mat src = cv::imread( argv[1],1 );
+  if( src.empty() ) { cout << "Cannot load " << argv[1] << endl; return -1; }
+
+  // Compute the HSV image, and decompose it into separate planes.
+  //
+  cv::Mat hsv;
+  cv::cvtColor(src, hsv, cv::COLOR_BGR2HSV);
+
+  float h_ranges[] = {0, 180}; // hue is [0, 180]
+  float s_ranges[] = {0, 256};
+  const float* ranges[] = {h_ranges, s_ranges};
+  int histSize[] = {30, 32}, ch[] = {0, 1};
+
+  cv::Mat hist;
+
+  // Compute the histogram
+  //
+  cv::calcHist(&hsv, 1, ch, cv::noArray(), hist, 2, histSize, ranges, true);
+  cv::normalize(hist, hist, 0, 255, cv::NORM_MINMAX);
+
+  int scale = 10;
+  cv::Mat hist_img(histSize[0]*scale, histSize[1]*scale, CV_8UC3);
+
+  // Draw our histogram.
+  //
+  for( int h = 0; h < histSize[0]; h++ ) {
+    for( int s = 0; s < histSize[1]; s++ ){
+      float hval = hist.at<float>(h, s);
+      cv::rectangle(
+	hist_img,
+	cv::Rect(h*scale,s*scale,scale,scale),
+	cv::Scalar::all(hval),
+	-1
+      );
+    }
+  }
+
+  cv::imshow("image", src);
+  cv::imshow("H-S histogram", hist_img);
+  cv::waitKey();
+  return 0;
+}

example_13-02.cpp

@@ -0,0 +1,162 @@
+// Example 13-2. Creating signatures from histograms for EMD; note that this code is the
+// source of the data in Table 13-1, in which the hand histogram is compared in different
+// lighting conditions
+
+#include <opencv2/opencv.hpp>
+#include <iostream>
+
+using namespace std;
+
+void help( char** argv ){
+  cout << "\nCall is:\n"
+  << argv[0] <<" modelImage0 testImage1 testImage2 badImage3\n\n"
+  << "for example: " << argv[0]
+  << " HandIndoorColor.jpg HandOutdoorColor.jpg "
+  << "HandOutdoorSunColor.jpg fruits.jpg\n"
+  << "\n";
+}
+
+// Compare 3 images' histograms
+int main( int argc, char** argv ) {
+  if( argc != 5 ) { help( argv ); return -1; }
+  vector<cv::Mat> src(5);
+  cv::Mat tmp;
+  int i;
+
+  tmp = cv::imread( argv[1], 1);
+  if( tmp.empty() ) {
+    cerr << "Error on reading image 1," << argv[1] << "\n" << endl;
+    help( argv );
+    return(-1);
+  }
+
+  // Parse the first image into two image halves divided halfway on y
+  //
+  cv::Size size = tmp.size();
+  int width = size.width;
+  int height = size.height;
+  int halfheight = height >> 1;
+
+  cout <<"Getting size [[" <<tmp.cols <<"] [" <<tmp.rows <<"]]\n" <<endl;
+  cout <<"Got size (w,h): (" <<size.width <<"," <<size.height <<")" <<endl;
+
+  src[0] = cv::Mat(cv::Size(width,halfheight), CV_8UC3);
+  src[1] = cv::Mat(cv::Size(width,halfheight), CV_8UC3);
+
+  // Divide the first image into top and bottom halves into src[0] and src[1]
+  //
+  cv::Mat_<cv::Vec3b>::iterator tmpit = tmp.begin<cv::Vec3b>();
+
+  // top half
+  //
+  cv::Mat_<cv::Vec3b>::iterator s0it = src[0].begin<cv::Vec3b>();
+  for(i = 0; i < width*halfheight; ++i, ++tmpit, ++s0it) *s0it = *tmpit;
+
+  // Bottom half
+  //
+  cv::Mat_<cv::Vec3b>::iterator s1it = src[1].begin<cv::Vec3b>();
+  for(i = 0; i < width*halfheight; ++i, ++tmpit, ++s1it) *s1it = *tmpit;
+
+  // Load the other three images
+  //
+  for(i = 2; i<5; ++i){
+    src[i] = cv::imread(argv[i], 1);
+    if(src[i].empty()) {
+      cerr << "Error on reading image " << i << ": " << argv[i] << "\n" << endl;
+      help( argv );
+      return(-1);
+    }
+  }
+
+  // Compute the HSV image, and decompose it into separate planes.
+  //
+  vector<cv::Mat> hsv(5), hist(5), hist_img(5);
+  int h_bins = 8;
+  int s_bins = 8;
+  int hist_size[] = { h_bins, s_bins }, ch[] = {0, 1};
+  float h_ranges[] = { 0, 180 }; // hue range is [0,180]
+  float s_ranges[] = { 0, 255 };
+  const float* ranges[] = { h_ranges, s_ranges };
+  int scale = 10;
+
+  for(i = 0; i<5; ++i) {
+    cv::cvtColor( src[i], hsv[i], cv::COLOR_BGR2HSV );
+    cv::calcHist( &hsv[i], 1, ch, cv::noArray(), hist[i], 2, hist_size, ranges, true );
+    cv::normalize( hist[i], hist[i], 0, 255, cv::NORM_MINMAX );
+    hist_img[i] = cv::Mat::zeros( hist_size[0]*scale, hist_size[1]*scale, CV_8UC3 );
+
+    // Draw our histogram For the 5 images
+    //
+    for( int h = 0; h < hist_size[0]; h++ )
+      for( int s = 0; s < hist_size[1]; s++ ) {
+	float hval = hist[i].at<float>(h, s);
+	cv::rectangle(
+	  hist_img[i],
+	  cv::Rect(h*scale, s*scale, scale, scale),
+	  cv::Scalar::all(hval),
+	  -1
+	);
+      }
+  }
+
+  // Display
+  //
+  cv::namedWindow( "Source0", 1 );cv::imshow( "Source0", src[0] );
+  cv::namedWindow( "HS Histogram0", 1 );cv::imshow( "HS Histogram0", hist_img[0] );
+
+  cv::namedWindow( "Source1", 1 );cv::imshow( "Source1", src[1] );
+  cv::namedWindow( "HS Histogram1", 1 ); cv::imshow( "HS Histogram1", hist_img[1] );
+
+  cv::namedWindow( "Source2", 1 ); cv::imshow( "Source2", src[2] );
+  cv::namedWindow( "HS Histogram2", 1 ); cv::imshow( "HS Histogram2", hist_img[2] );
+
+  cv::namedWindow( "Source3", 1 ); cv::imshow( "Source3", src[3] );
+  cv::namedWindow( "HS Histogram3", 1 ); cv::imshow( "HS Histogram3", hist_img[3] );
+
+  cv::namedWindow( "Source4", 1 ); cv::imshow( "Source4", src[4] );
+  cv::namedWindow( "HS Histogram4", 1 ); cv::imshow( "HS Histogram4", hist_img[4] );
+
+  // Compare the histogram src0 vs 1, vs 2, vs 3, vs 4
+  cout << "Comparison:\n"
+  << "Corr                Chi                Intersect                Bhat\n"<< endl;
+
+  for(i=1; i<5; ++i) { // For each histogram
+    cout << "Hist[0] vs Hist[" << i << "]: " << endl;;
+    for(int j=0; j<4; ++j) { // For each comparison type
+      cout << "method[" << j << "]: " << cv::compareHist(hist[0],hist[i],j) << " ";
+    }
+    cout << endl;
+  }
+
+  //Do EMD and report
+  //
+  vector<cv::Mat> sig(5);
+  cout << "\nEMD: " << endl;
+
+  // Oi Vey, parse histograms to earth movers signatures
+  //
+  for( i=0; i<5; ++i) {
+
+    vector<cv::Vec3f> sigv;
+
+    // (re)normalize histogram to make the bin weights sum to 1.
+    //
+    cv::normalize(hist[i], hist[i], 1, 0, cv::NORM_L1);
+    for( int h = 0; h < h_bins; h++ )
+      for( int s = 0; s < s_bins; s++ ) {
+	float bin_val = hist[i].at<float>(h, s);
+	if( bin_val != 0 )
+	  sigv.push_back( cv::Vec3f(bin_val, (float)h, (float)s));
+      }
+
+    // make Nx3 32fC1 matrix, where N is the number of nonzero histogram bins
+    //
+    sig[i] = cv::Mat(sigv).clone().reshape(1);
+    if( i > 0 )
+      cout << "Hist[0] vs Hist[" << i << "]: "
+	   << EMD(sig[0], sig[i], cv::DIST_L2) << endl;
+  }
+
+  cv::waitKey(0);
+
+}