// @tutorials imgproc module 18// @文件 Remap_Demo.cpp// @主题 图像重映射// @修改 CVer// @日期 2020年8月26日#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/imgproc.hpp"
#include <iostream>using namespace cv;
//h(x, y) = (I.cols - x, y)其中x，y分别对应map_x和map_y
//产生四种映射，按照ind的数值进行选择，对map_x和map_y赋值
void update_map( int &ind, Mat &map_x, Mat &map_y );int main(int argc, const char** argv)
{CommandLineParser parser(argc, argv, "{@image |chicky_512.png|input image name}");std::string filename = parser.get<std::string>(0);//读入图像Mat src = imread( samples::findFile( filename ), IMREAD_COLOR );if (src.empty()){std::cout << "Cannot read image: " << filename << std::endl;return -1;}//创建dst, map_x and map_y，大小与src相同:Mat dst(src.size(), src.type());Mat map_x(src.size(), CV_32FC1);Mat map_y(src.size(), CV_32FC1);//创建显示窗口，大小自动const char* remap_window = "Remap demo";namedWindow( remap_window, WINDOW_AUTOSIZE );///循环，根据ind选择remap的类型int ind = 0;for(;;){//更新map_x & map_y，并变换update_map(ind, map_x, map_y);remap( src, dst, map_x, map_y, INTER_LINEAR, BORDER_CONSTANT, Scalar(0, 0, 0) );//显示结果imshow( remap_window, dst );imshow("x", map_x);imshow("y", map_y);//暂停1秒.按ESC退出char c = (char)waitKey( 1000 );if( c == 27 ){break;}}return 0;
}
//根据前面的变换公式，需要计算所有位置坐标x，y变换后的值，即
//新的位置mat_x，mat_y，这里是四种变换示例
void update_map( int &ind, Mat &map_x, Mat &map_y )
{for( int i = 0; i < map_x.rows; i++ ){for( int j = 0; j < map_x.cols; j++ ){switch( ind ){case 0:if( j > map_x.cols*0.25 && j < map_x.cols*0.75 && i > map_x.rows*0.25 && i < map_x.rows*0.75 ){map_x.at<float>(i, j) = 2*( j - map_x.cols*0.25f ) + 0.5f;map_y.at<float>(i, j) = 2*( i - map_x.rows*0.25f ) + 0.5f;}else{map_x.at<float>(i, j) = 0;map_y.at<float>(i, j) = 0;}break;case 1:map_x.at<float>(i, j) = (float)j;map_y.at<float>(i, j) = (float)(map_x.rows - i);break;case 2:map_x.at<float>(i, j) = (float)(map_x.cols - j);map_y.at<float>(i, j) = (float)i;break;case 3:map_x.at<float>(i, j) = (float)(map_x.cols - j);map_y.at<float>(i, j) = (float)(map_x.rows - i);break;default:break;} // end of switch}}ind = (ind+1) % 4;
}