pointPolygonTest多边形检测

逃离我推掉我的手 2022-06-15 20:06 507阅读 0赞

根据官网提供的程序

#include "opencv2/highgui/highgui.hpp"
    #include "opencv2/imgproc/imgproc.hpp"
    #include <iostream>
    #include <stdio.h>
    #include <stdlib.h>
    
    using namespace cv;
    using namespace std;
    
    /** @function main */
    int main(int argc, char** argv)
    {
        /// 创建一个图形 
        const int r = 100;
        Mat src = Mat::zeros(Size(4 * r, 4 * r), CV_8UC1);
    
        /// 绘制一系列点创建一个轮廓:
        vector<Point2f> vert(6);
    
        vert[0] = Point(1.5*r, 1.34*r);
        vert[1] = Point(1 * r, 2 * r);
        vert[2] = Point(1.5*r, 2.866*r);
        vert[3] = Point(2.5*r, 2.866*r);
        vert[4] = Point(3 * r, 2 * r);
        vert[5] = Point(2.5*r, 1.34*r);
    
        for (int i = 0; i <= 5; i++)
        {
    
            cout << "vert[i]" << vert[i]<<endl;
        }
        /// 在src内部绘制
        for (int j = 0; j < 6; j++)
        {
            line(src, vert[j], vert[(j + 1) % 6], Scalar(255), 3, 8);//画线不取余时，报错，显示vector out of range
        }
    
        /// 得到轮廓
        vector<vector<Point> > contours; 
        vector<Vec4i> hierarchy;
        Mat src_copy = src.clone();
    
        findContours(src_copy, contours, hierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE);
    
        /// 计算到轮廓的距离
        Mat raw_dist(src.size(), CV_32FC1);
    
        for (int j = 0; j < src.rows; j++)
        {
            for (int i = 0; i < src.cols; i++)
            {
                raw_dist.at<float>(j, i) = pointPolygonTest(contours[0], Point2f(i, j), true);
    
            }
        }
    
        double minVal; double maxVal;
        minMaxLoc(raw_dist, &minVal, &maxVal, 0, 0, Mat());
        minVal = abs(minVal); maxVal = abs(maxVal);
    
        cout << minVal << endl;
        cout << maxVal << endl;
    
    
        /// 图形化的显示距离
        Mat drawing = Mat::zeros(src.size(), CV_8UC3);
    
        for (int j = 0; j < src.rows; j++)
        {
            for (int i = 0; i < src.cols; i++)
            {
                if (raw_dist.at<float>(j, i) < 0)//表示在轮廓线外部，因为pointPolygonTest里的measureDist为true
                {
                    drawing.at<Vec3b>(j, i)[0] = 255 - (int)abs(raw_dist.at<float>(j, i)) * 255 / minVal;
    
    
                }
                else if (raw_dist.at<float>(j, i) > 0)
                {
                    drawing.at<Vec3b>(j, i)[1] = 255 - (int)abs(raw_dist.at<float>(j, i) )* 255 / maxVal;
                }
                else
                {
                    drawing.at<Vec3b>(j, i)[0] = 255; drawing.at<Vec3b>(j, i)[1] = 255; drawing.at<Vec3b>(j, i)[2] = 255;
                }
            }
        }
    
        /// 创建窗口显示结果
        char* source_window = "Source";
        namedWindow(source_window, WINDOW_AUTOSIZE);
        imshow(source_window, src);
        namedWindow("Distance", WINDOW_AUTOSIZE);
        imshow("Distance", drawing);
    
        waitKey(0);
        return(0);
    }

![这里写图片描述][SouthEast]  
根据图中所示，在轮廓线内的为绿色，因为是通道1，外面是蓝色，通道为0

不知道为什么，画线不取余时，即vert\[(j + 1) % 6改成vert\[(j + 1) 报错，显示vector out of range 。希望过路大神能告知。  
/// 在src内部绘制  
for (int j = 0; j < 6; j++)  
\{  
line(src, vert\[j\], vert\[(j + 1) % 6\], Scalar(255), 3, 8);  
\}

[SouthEast]: /images/20220616/55dce9920b9a4e56b934ce1fe7b7195c.png