所谓的像素重映射就是：我们对原图的每一个像素值进行提取，然后经过一个函数变换，映射到我们空白的目标图片上，就得到一张新的图片，这个就是像素重映射。具体的基础知识，看这个博客：https://blog.csdn.net/qq_41167777/article/details/84947439
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下面这个代码运行，有好几种结果，主要就是，你按下 1，2，3，0，等等，会出现不同的图片展示。
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1 #include <opencv2/opencv.hpp>
2 #include <iostream>
3 using namespace std;
4 using namespace cv;
5
6 Mat src, dst, map_x, map_y;
7 const char* input_win = "input";
8 int index = 0;
9 const char* out_put = "hough-line-detection";
10 void update_map(void);
11 int main(int agrc, char** agrv) {
12 src = imread("C:\\Users\\32829\\Desktop\\111.jpg");
13 if (!src.data) {
14 printf("no load..\n");
15 return -1;
16 }
17 namedWindow(input_win, CV_WINDOW_AUTOSIZE);
18 namedWindow(out_put, CV_WINDOW_AUTOSIZE);
19 imshow(input_win, src);
20 map_x.create(src.size(), CV_32FC1);
21 map_y.create(src.size(), CV_32FC1);
22 int c = 0;
23 while (true) {
24 c = waitKey(500);
25 if ((char)c == 27) {
26 break;
27 }
28 index = c % 4;
29 update_map();
30 remap(src, dst, map_x, map_y, CV_INTER_LINEAR, BORDER_CONSTANT, Scalar(0, 255, 255));
31 imshow(out_put, dst);
32 }
33 }
34 void update_map(void) {
35 for (int row = 0; row < src.rows; row++) {
36 for (int col = 0; col < src.cols; col++) {
37 switch (index) {
38 case 0:
39 if (col > (src.cols*0.25) && col<(src.cols*0.75) && row>(src.rows*0.25) && row < (src.rows*0.75)) {
40 map_x.at<float>(row, col) = 2 * (col - (src.cols*0.25));
41 map_y.at<float>(row, col) = 2 * (row - (src.rows*0.25));
42 }
43 else {
44 map_x.at<float>(row, col) = 0;
45 map_y.at<float>(row, col) = 0;
46 }
47 break;
48 case 1:
49 map_x.at<float>(row, col) = (src.cols - col - 1);
50 map_y.at<float>(row, col) = row;
51 break;
52 case 2:
53 map_x.at<float>(row, col) = col;
54 map_y.at<float>(row, col) = (src.rows - row - 1);
55 break;
56 case 3:
57 map_x.at<float>(row, col) = (src.cols - col - 1);
58 map_y.at<float>(row, col) = (src.rows - row - 1);
59 break;
60 }
61 }
62 }
63 }
来源：https://www.cnblogs.com/xiaoyoucai/p/10197524.html