c++ - 鸟瞰opencv

Question

我想鸟瞰我用相机拍摄的图像，以便只显示白色车道。分辨率为 640x480。这是图片 - 我所做的是首先应用直方图均衡器和二进制阈值，然后定义我将在 getPerspectiveTransform 中使用的 4 个坐标和结果坐标。

    int bottom_leftx = 110;
    int bottom_lefty = 480;

    int upper_leftx = 260;
    int upper_lefty = 120;

    int upper_rightx = 410;
    int upper_righty = 120;

    int bottom_rightx = 560;
    int bottom_righty = 480;


    Point2f src_vertices[4];
    src_vertices[0] = Point(bottom_leftx, bottom_lefty);
    src_vertices[1] = Point(upper_leftx, upper_lefty);
    src_vertices[2] = Point(upper_righty, upper_righty);
    src_vertices[3] = Point(bottom_rightx, bottom_righty);


    Point2f dst_vertices[4];
    dst_vertices[0] = Point(0, 480);
    dst_vertices[1] = Point(0, 0);
    dst_vertices[2] = Point(640, 0);
    dst_vertices[3] = Point(640, 480);

然后应用 warpPerspective -

void getBirdView(Point2f *p1, Point2f *p2, const Mat& src, Mat& dst) {
    Mat warpMatrix = getPerspectiveTransform(p1, p2);

    warpPerspective(src, dst, warpMatrix, dst.size(), INTER_LINEAR, BORDER_CONSTANT);
}

而不是只得到两条平行线，我得到的是 -

那么我的结果是如何产生白色的呢？我哪里错了？

Answer 1

这是我的结果:

---

#include <opencv2/opencv.hpp>
#include <iostream>
using namespace cv;

void transform(Point2f* src_vertices, Point2f* dst_vertices, Mat& src, Mat &dst){
    Mat M = getPerspectiveTransform(src_vertices, dst_vertices);
    warpPerspective(src, dst, M, dst.size(), INTER_LINEAR, BORDER_CONSTANT);
}

int main(){
    Mat src = imread("test.png");

    Point2f src_vertices[4];
    src_vertices[0] = Point(270,120);
    src_vertices[1] = Point(395, 120);
    src_vertices[2] = Point(560, 480);
    src_vertices[3] = Point(110, 480);

    Point2f dst_vertices[4];
    dst_vertices[0] = Point(0, 0);
    dst_vertices[1] = Point(640, 0);
    dst_vertices[2] = Point(640, 480);
    dst_vertices[3] = Point(0, 480);

    Mat M = getPerspectiveTransform(src_vertices, dst_vertices);
    Mat dst(480, 640, CV_8UC3);
    warpPerspective(src, dst, M, dst.size(), INTER_LINEAR, BORDER_CONSTANT);

    Mat dst2(480, 640, CV_8UC3);
    transform(src_vertices, dst_vertices, src, dst2);


    imshow("src", src);
    imshow("dst", dst);
    imshow("dst2", dst2);
    waitKey();
}