Remapping image pixels

 

 

 

 Specific code as follows:

 

#include <opencv2/opencv.hpp>
#include <iostream>
#include <math.h>

using namespace cv;
Mat src, dst, map_x, map_y;
const char* OUTPUT_TITLE = "remap demo";
int index = 0;                             //输入默认为0
void update_map(void);                     //申明函数 
int main(int argc, char** argv) {        
    src = imread("L:/5.jpg");
     IF (! Src.data) { 
        the printf ( " Could Not Load Image ... \ n- " );
         return - . 1 ; 
    } 
    char input_win [] = " INPUT Image " ; 
    namedWindow (input_win, CV_WINDOW_AUTOSIZE); 
    namedWindow (OUTPUT_TITLE , CV_WINDOW_AUTOSIZE); 
    imshow (input_win, the src); 

    map_x.create (src.size (), CV_32FC1);        // define the size and floating point map_x.size 
    map_y.create (src.size (), CV_32FC1); 

    / / every 500ms check the input loop is updated once 
    int C = 0 ;
     the while (to true ) { 
        C = waitKey ( 500 );
         IF (( char ) C == 27 ) {                  // If the input is Esc to exit 
            BREAK ; 
        } 
        index =% C 4 ;                        // input values taking modulo 4 remainder operation 
        update_map ( );                        // Call update_map () function 
        remap (the src, DST, map_x, map_y, INTER_LINEAR, BORDER_CONSTANT, the Scalar ( 0 , 0 , 255 ));
         // remap function parameters: input image output image 34. 2. mapping table x, y 5. 6. default interpolation method 7. color
        imshow (OUTPUT_TITLE, DST); 
    } 

    return  0 ; 
} 

void update_map ( void ) {
     for ( int Row = 0 ; Row <src.rows; Row ++ ) {
         for ( int COL = 0 ; COL <src.cols; COL ++ ) {
             Switch (index) { 

            Case  0 :    // the original image is reduced by half, the center of the image is mapped to the 
                IF (COL> (src.cols * 0.25 ) && COL <= (src.cols * 0.75 ) && Row> (src.rows * 0.25 ) && Row <= (* src.rows 0.75)) {
                    map_x.at<float>(row, col) = 2 * (col - (src.cols*0.25));
                    map_y.at<float>(row, col) = 2 * (row - (src.rows*0.25));
                }
                else {  //边缘部分0像素填充
                    map_x.at<float>(row, col) = 0;
                    map_y.at<float>(row, col) = 0;
                }
                break;

            case 1://上下颠倒
                map_x.at<float>(row, col) = (src.cols - col - 1);
                map_y.at<float>(row, col) = row;
                break;

            case 2: //左右镜像
                map_x.at<float>(row, col) = col;
                map_y.at<float>(row, col) = (src.rows - row - 1);
                break;

            case 3://上下左右颠倒
                map_x.at<float>(row, col) = (src.cols - col - 1);
                map_y.at<float>(row, col) = (src.rows - row - 1);
                break;
            }

        }
    }
}

 

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