OpenCV Tutorials —— Remapping
重定向,也就是把图像中的像素从一个地方对应到另一个地方
To accomplish the mapping process, it might be necessary to do some interpolation for non-integer pixel locations, since there will not always be a one-to-one-pixel correspondence between source and destination images.
会涉及到插值 ~~ 可能像素点不是一一对应
程序中的四种处理方式
1,Reduce the picture to half its size and will display it in the middle:
for all pairs such that: and 缩放一半并将图像置于窗口中心
2,Turn the image upside down:
3,Reflect the image from left to right:
4,Combination of b and c:
remap
void remap(InputArray src, OutputArray dst, InputArray map1, InputArray map2, int interpolation, intborderMode=BORDER_CONSTANT, const Scalar& borderValue=Scalar())
Parameters:
- src – Source image.
- dst – Destination image. It has the same size as map1 and the same type as src .
- map1 – The first map of either (x,y) points or just x values having the type CV_16SC2 , CV_32FC1, or CV_32FC2 . See convertMaps() for details on converting a floating point representation to fixed-point for speed.
- map2 – The second map of y values having the type CV_16UC1 , CV_32FC1 , or none (empty map ifmap1 is (x,y) points), respectively.
- interpolation – Interpolation method (see resize() ). The method INTER_AREA is not supported by this function.
- borderMode – Pixel extrapolation method (see borderInterpolate() ). WhenborderMode=BORDER_TRANSPARENT , it means that the pixels in the destination image that corresponds to the “outliers” in the source image are not modified by the function.
- borderValue – Value used in case of a constant border. By default, it is 0.
Code
#include "stdafx.h" #include "opencv2/highgui/highgui.hpp" #include "opencv2/imgproc/imgproc.hpp" #include <iostream> #include <stdio.h> using namespace cv; /// Global variables Mat src, dst; Mat map_x, map_y; char* remap_window = "Remap demo"; int ind = 0; /// Function Headers void update_map( void ); /** * @function main */ int main( int argc, char** argv ) { /// Load the image src = imread( "zanxin.jpg", 1 ); /// Create dst, map_x and map_y with the same size as src: dst.create( src.size(), src.type() ); map_x.create( src.size(), CV_32FC1 ); map_y.create( src.size(), CV_32FC1 ); /// Create window namedWindow( remap_window, CV_WINDOW_AUTOSIZE ); /// Loop while( true ) { /// Each 1 sec. Press ESC to exit the program int c = waitKey( 1000 ); if( (char)c == 27 ) { break; } /// Update map_x & map_y. Then apply remap update_map(); remap( src, dst, map_x, map_y, CV_INTER_LINEAR, BORDER_CONSTANT, Scalar(0,0, 0) ); /// Display results imshow( remap_window, dst ); } return 0; } /** * @function update_map * @brief Fill the map_x and map_y matrices with 4 types of mappings */ void update_map( void ) { ind = ind%4; for( int j = 0; j < src.rows; j++ ) { for( int i = 0; i < src.cols; i++ ) { switch( ind ) { case 0: if( i > src.cols*0.25 && i < src.cols*0.75 && j > src.rows*0.25 && j < src.rows*0.75 ) { map_x.at<float>(j,i) = 2*( i - src.cols*0.25 ) + 0.5 ; map_y.at<float>(j,i) = 2*( j - src.rows*0.25 ) + 0.5 ; } else { map_x.at<float>(j,i) = 0 ; map_y.at<float>(j,i) = 0 ; } break; case 1: map_x.at<float>(j,i) = i ; map_y.at<float>(j,i) = src.rows - j ; break; case 2: map_x.at<float>(j,i) = src.cols - i ; map_y.at<float>(j,i) = j ; break; case 3: map_x.at<float>(j,i) = src.cols - i ; map_y.at<float>(j,i) = src.rows - j ; break; } // end of switch } } ind++; }
重点是构造 x,y坐标的map,用来映射像素点 ~~
郑重声明:本站内容如果来自互联网及其他传播媒体,其版权均属原媒体及文章作者所有。转载目的在于传递更多信息及用于网络分享,并不代表本站赞同其观点和对其真实性负责,也不构成任何其他建议。