本文是对OpenCV2.4.13文档的部分翻译，作个人学习之用，并不完整。
#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() { /// 载入原图像 src = imread("hand_sample2.jpg", 1 ); /// 将其转换为灰度图并模糊处理 cvtColor( src, src_gray, COLOR_BGR2GRAY ); blur( src_gray, src_gray, Size(3,3) ); /// 创建窗口，显示原图像 const char* source_window = "Source"; namedWindow( source_window, WINDOW_AUTOSIZE ); imshow( source_window, src ); //创建滑动块，选择阈值 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; /// 用阈值检测边缘 threshold( src_gray, threshold_output, thresh, 255, THRESH_BINARY ); /// 找到轮廓 findContours( threshold_output, contours, hierarchy, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, Point(0, 0) ); /// 为轮廓找到凸包对象 vector<vector<Point> >hull( contours.size() ); for( size_t i = 0; i < contours.size(); i++ ) { convexHull( Mat(contours[i]), hull[i], false ); } /// 画出轮廓和凸包对象 Mat drawing = Mat::zeros( threshold_output.size(), CV_8UC3 ); for( size_t i = 0; i< contours.size(); i++ ) { Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) ); drawContours( drawing, contours, (int)i, color, 1, 8, vector<Vec4i>(), 0, Point() ); drawContours( drawing, hull, (int)i, color, 1, 8, vector<Vec4i>(), 0, Point() ); } /// 显示画图结果 namedWindow( "Hull demo", WINDOW_AUTOSIZE ); imshow( "Hull demo", drawing ); }图像：
