opencv/samples/cpp/tutorial_code/snippets/imgproc_HoughLinesPointSet.cpp

#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    Mat lines;
    vector<Vec3d> line3d;
    vector<Point2f> point;
    const static float Points[20][2] = {
    { 0.0f,   369.0f }, { 10.0f,  364.0f }, { 20.0f,  358.0f }, { 30.0f,  352.0f },
    { 40.0f,  346.0f }, { 50.0f,  341.0f }, { 60.0f,  335.0f }, { 70.0f,  329.0f },
    { 80.0f,  323.0f }, { 90.0f,  318.0f }, { 100.0f, 312.0f }, { 110.0f, 306.0f },
    { 120.0f, 300.0f }, { 130.0f, 295.0f }, { 140.0f, 289.0f }, { 150.0f, 284.0f },
    { 160.0f, 277.0f }, { 170.0f, 271.0f }, { 180.0f, 266.0f }, { 190.0f, 260.0f }
    };

    for (int i = 0; i < 20; i++)
    {
        point.push_back(Point2f(Points[i][0],Points[i][1]));
    }

    double rhoMin = 0.0f, rhoMax = 360.0f, rhoStep = 1;
    double thetaMin = 0.0f, thetaMax = CV_PI / 2.0f, thetaStep = CV_PI / 180.0f;

    HoughLinesPointSet(point, lines, 20, 1,
                       rhoMin, rhoMax, rhoStep,
                       thetaMin, thetaMax, thetaStep);

    lines.copyTo(line3d);
    printf("votes:%d, rho:%.7f, theta:%.7f\n",(int)line3d.at(0).val[0], line3d.at(0).val[1], line3d.at(0).val[2]);
}