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目录
1--概念
2--Opencv API
3--实例代码
1--概念
从图像中的一个像素点获取其像素值，并将这个像素值映射到新图像中另一个像素点位置的过程；
为了完成整个映射过程，有时需对非整数像素位置进行插值，因为源图像和目标图像之间并不总是存在一对一的像素对应关系。
2--Opencv API
cv::remap(src, dst, map_x, map_y, cv::INTER_LINEAR, cv::BORDER_CONSTANT, cv::Scalar(0, 255, 255));
3--实例代码
# include
# include
# include
void update_map(cv::Mat src, cv::Mat map_x, cv:: Mat map_y, int idx){
for(int row = 0; row < map_x.rows; row++){
for(int col = 0; col < map_x.cols; col++){
switch (idx){
case 0: // 缩小
if (col > (map_x.cols*0.25) && col < (map_x.cols*0.75) && row > (map_x.rows*0.25) && row < (map_x.rows*0.75)){
map_x.at(row, col) = (float)(2 * (col - (map_x.cols*0.25) + 0.5));
map_y.at(row, col) = (float)(2 * (row - (map_x.rows*0.25) + 0.5));
}
else{
map_x.at(row, col) = 0;
map_y.at(row, col) = 0;
}
break;
case 1: // 左右颠倒
map_x.at(row, col) = (float)(map_x.cols - col - 1);
map_y.at(row, col) = (float)(row);
break;
case 2: // 上下颠倒
map_x.at(row, col) = (float)(col);
map_y.at(row, col) = (float)(map_x.rows - row - 1);
break;
case 3: // 上下左右颠倒
map_x.at(row, col) = (float)(map_x.cols - col - 1);
map_y.at(row, col) = (float)(map_x.rows - row - 1);
break;
}
}
}
}
int main(int argc, char** argv){
cv::Mat src;
cv::Mat map_x;
cv::Mat map_y;
cv::Mat dst;
int idx;
src = cv::imread("C:/Users/Liujinfu/Desktop/opencv_bilibili/test1.jpg");
if (src.empty()){
printf("could not load image..\n");
return -1;
}
cv::imshow("input", src);
map_x.create(src.size(), CV_32FC1);
map_y.create(src.size(), CV_32FC1);
int c = 0;
while(true){
c = cv::waitKey(10);
if(c == 27){ // esc键
break;
}
idx = c % 4;
update_map(src, map_x, map_y, idx);
cv::remap(src, dst, map_x, map_y, cv::INTER_LINEAR, cv::BORDER_CONSTANT, cv::Scalar(0, 255, 255));
cv::imshow("output", dst);
}
return 0;
}
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