OpenCV  4.10.0-dev
Open Source Computer Vision
samples/cpp/tutorial_code/Histograms_Matching/MatchTemplate_Demo.cpp

An example using Template Matching algorithm

#include <iostream>
using namespace std;
using namespace cv;
bool use_mask;
Mat img; Mat templ; Mat mask; Mat result;
const char* image_window = "Source Image";
const char* result_window = "Result window";
int match_method;
int max_Trackbar = 5;
void MatchingMethod( int, void* );
const char* keys =
"{ help h| | Print help message. }"
"{ @input1 | Template_Matching_Original_Image.jpg | image_name }"
"{ @input2 | Template_Matching_Template_Image.jpg | template_name }"
"{ @input3 | | mask_name }";
int main( int argc, char** argv )
{
CommandLineParser parser( argc, argv, keys );
samples::addSamplesDataSearchSubDirectory( "doc/tutorials/imgproc/histograms/template_matching/images" );
img = imread( samples::findFile( parser.get<String>("@input1") ) );
templ = imread( samples::findFile( parser.get<String>("@input2") ), IMREAD_COLOR );
if(argc > 3) {
use_mask = true;
mask = imread(samples::findFile( parser.get<String>("@input3") ), IMREAD_COLOR );
}
if(img.empty() || templ.empty() || (use_mask && mask.empty()))
{
cout << "Can't read one of the images" << endl;
return EXIT_FAILURE;
}
namedWindow( image_window, WINDOW_AUTOSIZE );
namedWindow( result_window, WINDOW_AUTOSIZE );
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";
createTrackbar( trackbar_label, image_window, &match_method, max_Trackbar, MatchingMethod );
MatchingMethod( 0, 0 );
waitKey(0);
return EXIT_SUCCESS;
}
void MatchingMethod( int, void* )
{
Mat img_display;
img.copyTo( img_display );
int result_cols = img.cols - templ.cols + 1;
int result_rows = img.rows - templ.rows + 1;
result.create( result_rows, result_cols, CV_32FC1 );
bool method_accepts_mask = (TM_SQDIFF == match_method || match_method == TM_CCORR_NORMED);
if (use_mask && method_accepts_mask)
{ matchTemplate( img, templ, result, match_method, mask); }
else
{ matchTemplate( img, templ, result, match_method); }
normalize( result, result, 0, 1, NORM_MINMAX, -1, Mat() );
double minVal; double maxVal; Point minLoc; Point maxLoc;
Point matchLoc;
minMaxLoc( result, &minVal, &maxVal, &minLoc, &maxLoc, Mat() );
if( match_method == TM_SQDIFF || match_method == TM_SQDIFF_NORMED )
{ matchLoc = minLoc; }
else
{ matchLoc = maxLoc; }
rectangle( img_display, matchLoc, Point( matchLoc.x + templ.cols , matchLoc.y + templ.rows ), Scalar::all(0), 2, 8, 0 );
rectangle( result, matchLoc, Point( matchLoc.x + templ.cols , matchLoc.y + templ.rows ), Scalar::all(0), 2, 8, 0 );
imshow( image_window, img_display );
imshow( result_window, result );
return;
}
void minMaxLoc(InputArray src, double *minVal, double *maxVal=0, Point *minLoc=0, Point *maxLoc=0, InputArray mask=noArray())
Finds the global minimum and maximum in an array.
@ NORM_MINMAX
flag
Definition: base.hpp:207
Point2i Point
Definition: types.hpp:209
std::string String
Definition: cvstd.hpp:149
Vec< _Tp, cn > normalize(const Vec< _Tp, cn > &v)
#define CV_32FC1
Definition: interface.h:118
cv::String findFile(const cv::String &relative_path, bool required=true, bool silentMode=false)
Try to find requested data file.
void addSamplesDataSearchSubDirectory(const cv::String &subdir)
Append samples search data sub directory.
GMat mask(const GMat &src, const GMat &mask)
Applies a mask to a matrix.
@ WINDOW_AUTOSIZE
the user cannot resize the window, the size is constrainted by the image displayed.
Definition: highgui.hpp:144
void imshow(const String &winname, InputArray mat)
Displays an image in the specified window.
int waitKey(int delay=0)
Waits for a pressed key.
void namedWindow(const String &winname, int flags=WINDOW_AUTOSIZE)
Creates a window.
int createTrackbar(const String &trackbarname, const String &winname, int *value, int count, TrackbarCallback onChange=0, void *userdata=0)
Creates a trackbar and attaches it to the specified window.
@ IMREAD_COLOR
Same as IMREAD_COLOR_BGR.
Definition: imgcodecs.hpp:72
CV_EXPORTS_W Mat imread(const String &filename, int flags=IMREAD_COLOR_BGR)
Loads an image from a file.
void rectangle(InputOutputArray img, Point pt1, Point pt2, const Scalar &color, int thickness=1, int lineType=LINE_8, int shift=0)
Draws a simple, thick, or filled up-right rectangle.
void matchTemplate(InputArray image, InputArray templ, OutputArray result, int method, InputArray mask=noArray())
Compares a template against overlapped image regions.
@ TM_SQDIFF_NORMED
Definition: imgproc.hpp:3846
@ TM_SQDIFF
Definition: imgproc.hpp:3842
@ TM_CCORR_NORMED
Definition: imgproc.hpp:3857
int main(int argc, char *argv[])
Definition: highgui_qt.cpp:3
Definition: affine.hpp:52