OpenCV 显示图像的凸包 Convex Hull 效果

目的

本文将教你如何使用 OpenCV 函数 convexHull

代码

代码如下所示，可从这里 下载

 #include "opencv2/highgui/highgui.hpp" #include "opencv2/imgproc/imgproc.hpp" #include <iostream> #include <stdio.h> #include <stdlib.h> 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( " Threshold:", "Source", &thresh, max_thresh, thresh_callback );   thresh_callback( 0, 0 );   waitKey(0);   return(0); } /** @function thresh_callback */ void thresh_callback(int, void* ) {   Mat src_copy = src.clone();   Mat threshold_output;   vector<vector<Point> > contours;   vector<Vec4i> hierarchy;   /// Detect edges using Threshold   threshold( src_gray, threshold_output, thresh, 255, THRESH_BINARY );   /// Find contours   findContours( threshold_output, contours, hierarchy, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, Point(0, 0) );   /// Find the convex hull object for each contour   vector<vector<Point> >hull( contours.size() );   for( int i = 0; i < contours.size(); i++ )      {  convexHull( Mat(contours[i]), hull[i], false ); }   /// Draw contours + hull results   Mat drawing = Mat::zeros( threshold_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, 1, 8, vector<Vec4i>(), 0, Point() );        drawContours( drawing, hull, i, color, 1, 8, vector<Vec4i>(), 0, Point() );      }   /// Show in a window   namedWindow( "Hull demo", CV_WINDOW_AUTOSIZE );   imshow( "Hull demo", drawing ); }

结果