OpenCV(C++版)轮廓(contour)检测

findContours 和 drawContours 的例子：来自

 #include "stdafx.h"
#include <opencv2/opencv.hpp>
using namespace std;
using namespace cv;
int main( int argc, char** argv )
{    Mat src;
    // the first command-line parameter must be a filename of the binary (black-n-white) image
    if( argc != 2 || !(src=imread(argv[1], 0)).data)
        return -1;
    Mat dst = Mat::zeros(src.rows, src.cols, CV_8UC3);
    src = src > 50;
    namedWindow( "Source", 1 );
    imshow( "Source", src );
    vector<vector<Point> > contours;
    vector<Vec4i> hierarchy;
    findContours( src, contours, hierarchy, CV_RETR_CCOMP , CV_CHAIN_APPROX_NONE );
    // iterate through all the top-level contours,draw each connected component with its own random color
    int idx = 0;
    for( ; idx >= 0; idx = hierarchy[idx][0] )
    {
        Scalar color( rand()&255, rand()&255, rand()&255 );
        drawContours( dst, contours, idx, color, CV_FILLED, 8, hierarchy );
    }
    namedWindow( "Components", 1 );
    imshow( "Components", dst );
    waitKey(0);
}

〉按轮廓线，提取图像中闭合区域：findContours，对应的C接口为cvFindContours。

> 加入canny边缘检测，可以得到另一组结果。

结果：