（原）opencv直線擬合fitLine

轉載請注明出處

http://www.cnblogs.com/darkknightzh/p/5486234.html

參考網址：

http://blog.csdn.net/thefutureisour/article/details/7599537

Mat img(60, 60, CV_8UC1, Scalar(0));
    std::vector<Point2f> points;
    points.push_back(Point2f(10.5, 10.2));
    points.push_back(Point2f(20.6, 20.7));
    points.push_back(Point2f(33.5, 30.2));
    points.push_back(Point2f(40.7, 50));

    //儲存擬合直線的容器  
    Vec4f line;
    //直線擬合函數  
    fitLine(Mat(points), line, CV_DIST_L1, 0, 0.01, 0.01);
    std::cout << "line: (" << line[0] << "," << line[1] << ")(" << line[2] << "," << line[3] << ")\n";

    for (auto i = 0; i < points.size(); i++)
        cv::circle(img, cvPoint(points.at(i).x, points.at(i).y), 2, Scalar(255));

    double k = line[1] / line[0];
    double step = 40;
    cv::line(img, cvPoint(line[2] - step, line[3] - k*step), cvPoint(line[2] + step, k*step + line[3]), Scalar(255));

    imshow("img", img);
    waitKey(0);

擬合的結果Vec4f類型的line中的前兩個值 給出的是直線的方向的單位向量，后兩個值給出的是該直線通過的一個點（轉自參考網址）。