opencv学习笔记9 查找绘制轮廓

一。查找绘制轮廓

1.查找轮廓

 

 2.绘制轮廓

#include<opencv.hpp>
#include<iostream>
#include<vector>
using namespace std;
using namespace cv;
int main()
{
    Mat srcImg = imread("F:/opencv/lena.jpg", 0);
    imshow("yuantu", srcImg);
    Mat dstImg = Mat::zeros(srcImg.rows, srcImg.cols, srcImg.type());
    threshold(srcImg, srcImg, 119, 255, THRESH_BINARY);//通过threshold进行二值化
    imshow("二值图", srcImg);
    vector<vector<Point>>contours; //每个轮廓由多个Point组成，有多个轮廓
    vector<Vec4i>hierarchy; //保存每个轮廓的4个信息，hierarchy[i]代表第i个轮廓 hierarchy[i][0]表示第i个轮廓的后一个轮廓
    findContours(srcImg, contours, hierarchy, RETR_CCOMP, CHAIN_APPROX_SIMPLE); //寻找轮廓，保存轮廓信息，和轮廓的索引信息
    int index = 0; //第1个轮廓的索引
    for (; index >= 0; index = hierarchy[index][0]) //index++，若index后面没有对应项，为-1
    {
        Scalar color(rand() % 255, rand() % 255, rand() % 255);
        drawContours(dstImg, contours, index, color, FILLED, 8, hierarchy);//画轮廓
    }
    imshow("轮廓", dstImg);
    waitKey();
    return 0;
}