Opencv4 matchTemplate（模板）使用

 1 Mat imgMat = imread("fish.png", IMREAD_GRAYSCALE);      //  原图
 2     Mat m1 = imread("fish_single.png", IMREAD_GRAYSCALE);   //  模板图
 3     Mat m2;
 4     Mat m3;
 5     Mat canny_out;
 6     imshow("m1", m1);
 7 
 8 
 9     matchTemplate(imgMat, m1, m2, TM_CCOEFF_NORMED );
10 
11     imshow("m2", m2);
12     double minVal;
13     double maxVal;
14     Point minLoc;
15     Point maxLoc;
16     minMaxLoc(m2, &minVal, &maxVal, &minLoc, &maxLoc);  //  提取极值
17     imgMat.copyTo(m3);
18     rectangle(m3, Point(maxLoc), Point(maxLoc.x + m1.cols, maxLoc.y + m1.rows),
19               Scalar(0, 0, 255), 3);　　//  绘制得分最高结果的矩形边界
20     imshow("m3", m3);
21 
22     //  给所有阈值大于0.8的结果绘制矩形
23     float threshold = 0.8;
24     for(int row = 0; row < m2.rows; row++)
25     {
26         for (int col = 0;col < m2.cols; col++ )
27         {
28             //  Mat.at<float>(i, j)   返回对应float值
29             float value = m2.at<float>(row, col);
30             if(value > threshold)
31                 rectangle(imgMat, Point(col, row), Point(col + m1.cols, row + m1.rows),
32                           Scalar(0, 0, 255));
33         }
34     }
35     imshow("imgMat", imgMat);