diff --git a/samples/cpp/tutorial_code/ShapeDescriptors/moments_demo.cpp b/samples/cpp/tutorial_code/ShapeDescriptors/moments_demo.cpp new file mode 100644 index 0000000000..e83b6094e5 --- /dev/null +++ b/samples/cpp/tutorial_code/ShapeDescriptors/moments_demo.cpp @@ -0,0 +1,95 @@ +/** + * @function moments_demo.cpp + * @brief Demo code to calculate moments + * @author OpenCV team + */ + +#include "opencv2/highgui/highgui.hpp" +#include "opencv2/imgproc/imgproc.hpp" +#include +#include +#include + +using namespace cv; +using namespace std; + +Mat src; Mat src_gray; +int thresh = 100; +int max_thresh = 255; +RNG rng(12345); + +/// Function header +void thresh_callback(int, void* ); + +/** + * @function main + */ +int main( int argc, char** argv ) +{ + /// Load source image and convert it to gray + src = imread( argv[1], 1 ); + + /// Convert image to gray and blur it + cvtColor( src, src_gray, CV_BGR2GRAY ); + blur( src_gray, src_gray, Size(3,3) ); + + /// Create Window + char* source_window = "Source"; + namedWindow( source_window, CV_WINDOW_AUTOSIZE ); + imshow( source_window, src ); + + createTrackbar( " Canny thresh:", "Source", &thresh, max_thresh, thresh_callback ); + thresh_callback( 0, 0 ); + + waitKey(0); + return(0); +} + +/** + * @function thresh_callback + */ +void thresh_callback(int, void* ) +{ + Mat canny_output; + vector > contours; + vector hierarchy; + + /// Detect edges using canny + Canny( src_gray, canny_output, thresh, thresh*2, 3 ); + /// Find contours + findContours( canny_output, contours, hierarchy, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, Point(0, 0) ); + + /// Get the moments + vector mu(contours.size() ); + for( int i = 0; i < contours.size(); i++ ) + { mu[i] = moments( contours[i], false ); } + + /// Get the mass centers: + vector mc( contours.size() ); + for( int i = 0; i < contours.size(); i++ ) + { mc[i] = Point2f( mu[i].m10/mu[i].m00 , mu[i].m01/mu[i].m00 ); } + + /// Draw contours + Mat drawing = Mat::zeros( canny_output.size(), CV_8UC3 ); + for( int i = 0; i< contours.size(); i++ ) + { + Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) ); + drawContours( drawing, contours, i, color, 2, 8, hierarchy, 0, Point() ); + circle( drawing, mc[i], 4, color, -1, 8, 0 ); + } + + /// Show in a window + namedWindow( "Contours", CV_WINDOW_AUTOSIZE ); + imshow( "Contours", drawing ); + + /// Calculate the area with the moments 00 and compare with the result of the OpenCV function + printf("\t Info: Area and Contour Length \n"); + for( int i = 0; i< contours.size(); i++ ) + { + printf(" * Contour[%d] - Area (M_00) = %.2f - Area OpenCV: %.2f - Length: %.2f \n", i, mu[i].m00, contourArea(contours[i]), arcLength( contours[i], true ) ); + Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) ); + drawContours( drawing, contours, i, color, 2, 8, hierarchy, 0, Point() ); + circle( drawing, mc[i], 4, color, -1, 8, 0 ); + } +} +