samples/cpp/tutorial_code/Histograms_Matching/MatchTemplate_Demo.cpp#

An example using Template Matching algorithm

  1/**
  2 * @file MatchTemplate_Demo.cpp
  3 * @brief Sample code to use the function MatchTemplate
  4 * @author OpenCV team
  5 */
  6
  7#include "opencv2/imgcodecs.hpp"
  8#include "opencv2/highgui.hpp"
  9#include "opencv2/imgproc.hpp"
 10#include <iostream>
 11
 12using namespace std;
 13using namespace cv;
 14
 15//! [declare]
 16/// Global Variables
 17bool use_mask;
 18Mat img; Mat templ; Mat mask; Mat result;
 19const char* image_window = "Source Image";
 20const char* result_window = "Result window";
 21
 22int match_method;
 23int max_Trackbar = 5;
 24//! [declare]
 25
 26/// Function Headers
 27void MatchingMethod( int, void* );
 28
 29const char* keys =
 30"{ help  h| | Print help message. }"
 31"{ @input1 | Template_Matching_Original_Image.jpg | image_name }"
 32"{ @input2 | Template_Matching_Template_Image.jpg | template_name }"
 33"{ @input3 |  | mask_name }";
 34
 35/**
 36 * @function main
 37 */
 38int main( int argc, char** argv )
 39{
 40  CommandLineParser parser( argc, argv, keys );
 41  samples::addSamplesDataSearchSubDirectory( "doc/tutorials/imgproc/histograms/template_matching/images" );
 42
 43  //! [load_image]
 44  /// Load image and template
 45  img = imread( samples::findFile( parser.get<String>("@input1") ) );
 46  templ = imread( samples::findFile( parser.get<String>("@input2") ), IMREAD_COLOR );
 47
 48  if(argc > 3) {
 49    use_mask = true;
 50    mask = imread(samples::findFile( parser.get<String>("@input3") ), IMREAD_COLOR );
 51  }
 52
 53  if(img.empty() || templ.empty() || (use_mask && mask.empty()))
 54  {
 55    cout << "Can't read one of the images" << endl;
 56    return EXIT_FAILURE;
 57  }
 58  //! [load_image]
 59
 60  //! [create_windows]
 61  /// Create windows
 62  namedWindow( image_window, WINDOW_AUTOSIZE );
 63  namedWindow( result_window, WINDOW_AUTOSIZE );
 64  //! [create_windows]
 65
 66  //! [create_trackbar]
 67  /// Create Trackbar
 68  const char* trackbar_label = "Method: \n 0: SQDIFF \n 1: SQDIFF NORMED \n 2: TM CCORR \n 3: TM CCORR NORMED \n 4: TM COEFF \n 5: TM COEFF NORMED";
 69  createTrackbar( trackbar_label, image_window, &match_method, max_Trackbar, MatchingMethod );
 70  //! [create_trackbar]
 71
 72  MatchingMethod( 0, 0 );
 73
 74  //! [wait_key]
 75  waitKey(0);
 76  return EXIT_SUCCESS;
 77  //! [wait_key]
 78}
 79
 80/**
 81 * @function MatchingMethod
 82 * @brief Trackbar callback
 83 */
 84void MatchingMethod( int, void* )
 85{
 86  //! [copy_source]
 87  /// Source image to display
 88  Mat img_display;
 89  img.copyTo( img_display );
 90  //! [copy_source]
 91
 92  //! [create_result_matrix]
 93  /// Create the result matrix
 94  int result_cols = img.cols - templ.cols + 1;
 95  int result_rows = img.rows - templ.rows + 1;
 96
 97  result.create( result_rows, result_cols, CV_32FC1 );
 98  //! [create_result_matrix]
 99
100  //! [match_template]
101  /// Do the Matching and Normalize
102  bool method_accepts_mask = (TM_SQDIFF == match_method || match_method == TM_CCORR_NORMED);
103  if (use_mask && method_accepts_mask)
104    { matchTemplate( img, templ, result, match_method, mask); }
105  else
106    { matchTemplate( img, templ, result, match_method); }
107  //! [match_template]
108
109  //! [normalize]
110  normalize( result, result, 0, 1, NORM_MINMAX, -1, Mat() );
111  //! [normalize]
112
113  //! [best_match]
114  /// Localizing the best match with minMaxLoc
115  double minVal; double maxVal; Point minLoc; Point maxLoc;
116  Point matchLoc;
117
118  minMaxLoc( result, &minVal, &maxVal, &minLoc, &maxLoc, Mat() );
119  //! [best_match]
120
121  //! [match_loc]
122  /// For SQDIFF and SQDIFF_NORMED, the best matches are lower values. For all the other methods, the higher the better
123  if( match_method  == TM_SQDIFF || match_method == TM_SQDIFF_NORMED )
124    { matchLoc = minLoc; }
125  else
126    { matchLoc = maxLoc; }
127  //! [match_loc]
128
129  //! [imshow]
130  /// Show me what you got
131  rectangle( img_display, matchLoc, Point( matchLoc.x + templ.cols , matchLoc.y + templ.rows ), Scalar::all(0), 2, 8, 0 );
132  rectangle( result, matchLoc, Point( matchLoc.x + templ.cols , matchLoc.y + templ.rows ), Scalar::all(0), 2, 8, 0 );
133
134  imshow( image_window, img_display );
135  imshow( result_window, result );
136  //! [imshow]
137
138  return;
139}