opencv —— approxPolyDP 生成逼近曲线

//作品《抽象的牛》
#include<opencv.hpp>
#include<iostream>
using namespace cv;
using namespace std;
int main() {
    Mat src = imread("C:/Users/齐明洋/Desktop/6.jpg");
    imshow("src", src);

    Mat gray, bin_img;
    cvtColor(src, gray, COLOR_BGR2GRAY); //将原图转换为灰度图
    imshow("gray", gray);

    //二值化
    threshold(gray, bin_img, 150, 255, THRESH_BINARY_INV);
    Mat kernel = getStructuringElement(MORPH_RECT, Size(3, 3));
    morphologyEx(bin_img, bin_img, MORPH_CLOSE, kernel, Point(-1, -1), 2);//闭操作，先膨胀后腐蚀，消除小黑点
    imshow("bin_img", bin_img);

    //寻找轮廓
    vector<vector<Point> >contours;
    findContours(bin_img, contours, RETR_TREE, CHAIN_APPROX_NONE);

    //生成逼近曲线
    Mat dst = Mat::zeros(src.size(), src.type());
    RNG rngs = { 12345 };
    vector<vector<Point> >approx_contours(contours.size());//存放逼近曲线的数组
    for (int i = 0; i < contours.size(); i++) {
        approxPolyDP(contours[i], approx_contours[i], 40, true);
        Scalar colors = Scalar(rngs.uniform(0, 255), rngs.uniform(0, 255), rngs.uniform(0, 255));
        drawContours(dst, approx_contours, i, colors, 3);
    }
    imshow("dst", dst);

    waitKey(0);
}