opencv_霍夫变换

//1  累计霍夫线变换
#include <opencv2/opencv.hpp>
#include <iostream>
using namespace std;
using namespace cv;
int thre, minLineLength, maxLineGap;
Mat src, dst;
void on_HoughLines(int, void *);
int main() {
    Mat ori = imread("chess1.jpg");
    namedWindow("dst");
    imshow("origin", ori);
    Canny(ori, src, 50, 200, 3);
    cvtColor(src, dst, CV_GRAY2BGR);
    imshow("canny image", src);
    thre = 80;
    minLineLength = 50;
    maxLineGap = 10;
    createTrackbar("threshold:", "dst", &thre, 300, on_HoughLines);
    createTrackbar("minLine  :", "dst", &minLineLength, 300, on_HoughLines);
    createTrackbar("maxGap   :", "dst", &maxLineGap, 20, on_HoughLines);

    on_HoughLines(thre, 0);
    on_HoughLines(minLineLength, 0);
    on_HoughLines(maxLineGap, 0);

    waitKey(0);
}
//
void on_HoughLines(int, void *) {
    vector<Vec4i> lines;
    Mat dstImage = dst.clone();
    Mat srcImage = src.clone();
    HoughLinesP(srcImage, lines, 1, CV_PI / 180, thre, minLineLength, maxLineGap);
    for (size_t i = 0; i < lines.size(); i++) {
        Vec4i l = lines[i];
        line(dstImage, Point(l[0], l[1]), Point(l[2], l[3]), Scalar(186, 88, 255), 2);
    }
    imshow("dst", dstImage);
}

//2  霍夫圆变换
#include <opencv2/opencv.hpp>
#include <iostream>
using namespace std;
using namespace cv;
int main() {
    Mat src = imread("planet_glow.jpg");
    namedWindow("origin");
    imshow("origin", src);
    //转出灰度图，并进行平滑,因为要进行边缘检测，最好进行平滑
    Mat gray;
    cvtColor(src, gray, CV_BGR2GRAY);
    imshow("gray", gray);;
    Mat dst;
    medianBlur(gray, dst, 5);;
    imshow("median filter", dst);
    vector<Vec3f> circles;
    HoughCircles(dst, circles, HOUGH_GRADIENT, 1, 120, 100, 30, 0, 0);
    for (size_t i = 0; i < circles.size(); i++) {
        Point center(cvRound(circles[i][0]), cvRound(circles[i][1]));
        int radius = cvRound(circles[i][2]);
        //绘制圆心
        circle(src, center, 2, Scalar(0, 255, 0), 2);
        //绘制轮廓
        circle(src, center, radius, Scalar(0, 255, 0), 2);
    }
    imshow("result", src);
    waitKey(0);
}