Question

你好每个王牌我都有一些问题这是我的代码可以教我如何在中心的视频中画一条直线？以及如何减少视频中的绿线，因为我想找到消失点。

#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>e
using namespace cv;
using namespace std;
Point2f center(0,0);
Point2f computeIntersect(Vec4i a, Vec4i b)

{
    int x1 = a[0], y1 = a[1], x2 = a[2], y2 = a[3], x3 = b[0], y3 = b[1], x4 = b[2], y4 = b[3];
    float denom;

    if (float d = ((float)(x1 - x2) * (y3 - y4)) - ((y1 - y2) * (x3 - x4)))
    {
            Point2f pt;
            pt.x = ((x1 * y2 - y1 * x2) * (x3 - x4) - (x1 - x2) * (x3 * y4 - y3 * x4)) / d;
            pt.y = ((x1 * y2 - y1 * x2) * (y3 - y4) - (y1 - y2) * (x3 * y4 - y3 * x4)) / d;
            return pt;
    }
    else
            return Point2f(-1, -1);


}
void sortCorners(std::vector<Point2f>& corners, Point2f center)

{
    std::vector<Point2f> top, bot;





    for (int i = 0; i < corners.size(); i++)
    {
            if (corners[i].y < center.y)
                    top.push_back(corners[i]);
            else
                    bot.push_back(corners[i]);
    }

    Point2f tl = top[0].x > top[1].x ? top[1] : top[0];
    Point2f tr = top[0].x > top[1].x ? top[0] : top[1];
    Point2f bl = bot[0].x > bot[1].x ? bot[1] : bot[0];
    Point2f br = bot[0].x > bot[1].x ? bot[0] : bot[1];

    corners.clear();
    corners.push_back(tl);
    corners.push_back(tr);
    corners.push_back(br);
    corners.push_back(bl);
}
Mat src;
int main()

{







VideoCapture cap("C://pic/way.mp4");
while ( cap.isOpened() )
{
cap >> src;





    //Mat src = imread("D:\\11.jpg");
    if (src.empty())
            return -1;

    Mat bw;
    cvtColor(src, bw, CV_BGR2GRAY);
    blur(bw, bw, Size(3, 3));
    Canny(bw, bw, 150, 100, 3);

    std::vector<Vec4i> lines;
    HoughLinesP(bw, lines, 1, CV_PI/180, 70, 30, 10);

    // Expand the lines
    for (int i = 0; i < lines.size(); i++)
    {
            Vec4i v = lines[i];
            lines[i][0] = 0;
            lines[i][1] = ((float)v[1] - v[3]) / (v[0] - v[2]) * -v[0] + v[1]; 
            lines[i][2] = src.cols; 
            lines[i][3] = ((float)v[1] - v[3]) / (v[0] - v[2]) * (src.cols - v[2]) + v[3];
    }

    std::vector<Point2f> corners;
    for (int i = 0; i < lines.size(); i++)
    {
            for (int j = i+1; j < lines.size(); j++)
            {
                    Point2f pt = computeIntersect(lines[i], lines[j]);
                    if (pt.x >= 0 && pt.y >= 0)
                            corners.push_back(pt);
            }
    }

    std::vector<Point2f> approx;
    approxPolyDP(Mat(corners), approx, arcLength(Mat(corners), true) * 0.02, true);


    // Get mass center
    for (int i = 0; i < corners.size(); i++)
            center += corners[i];
    center *= (1. / corners.size());

    sortCorners(corners, center);

    Mat dst = src.clone();

    // Draw lines
    for (int i = 0; i < lines.size(); i++)
    {
            Vec4i v = lines[i];
            line(dst, Point(v[0], v[1]), Point(v[2], v[3]), CV_RGB(0,255,0));
    }

    // Draw corner points

    circle(dst, corners[3], 3, CV_RGB(255,255,255), 2);
        cout << "Detected " << corners[3] << "\n";

    // Draw mass center
    circle(dst, center, 3, CV_RGB(255,255,0), 2);

    Mat quad = Mat::zeros(300, 220, CV_8UC3);

    std::vector<Point2f> quad_pts;
    quad_pts.push_back(Point2f(0, 0));
    quad_pts.push_back(Point2f(quad.cols, 0));
    quad_pts.push_back(Point2f(quad.cols, quad.rows));
    quad_pts.push_back(Point2f(0, quad.rows));

    Mat transmtx = getPerspectiveTransform(corners, quad_pts);
    warpPerspective(src, quad, transmtx, quad.size());

    imshow("image", bw);
    imshow("images", dst);

    if(waitKey(27) >= 0)  break; }




 return 0;}

Answer 1

检查this。希望它会有所帮助，请告诉我。

如何在opencv中绘制线条

1 个答案: