opencv學習筆記20-像素重映射remap

只用來記錄學習筆記

代碼：

	map_x.create(src.size(), CV_32FC1);
	map_y.create(src.size(), CV_32FC1);
	namedWindow(output_title, CV_WINDOW_AUTOSIZE);
	update_map();
	remap(src, dst, map_x, map_y, INTER_LINEAR, BORDER_CONSTANT, Scalar(0, 255, 255));
	//src: 輸入圖像
	//dst:輸出圖像
	//map_x:x 映射表 CV_32FC1/CV_32FC2
	//map_y:y 映射表 CV_32FC1/CV_32FC2
	//INTER_LINEAR: 選擇的插值方法，常見線性插值，可選擇立方等
	//BORDER_CONSTANT: BORDER_CONSTANT 邊緣填充方式
	//Scalar(0, 255, 255): color 
	imshow(output_title, dst);

邊緣填充筆記：opencv學習筆記14-邊緣填充
方法（函數）：

void update_map(void) {
	for (int row = 0; row < src.rows; row++) {
		for (int col = 0; col < src.cols; col++) {
			switch (index)
			{
			case 0: //縮小成一半
				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) - 0.5);
					map_y.at<float>(row, col) = 2 * (row - (src.rows*0.25) - 0.5);
				}
				else {
					map_x.at<float>(row, col) = 0;
					map_y.at<float>(row, col) = 0;
				}
				break;
			case 1: //左右顛倒
				map_x.at<float>(row, col) = src.cols - col - 1;
				map_y.at<float>(row, col) = row;
				break;
			case 2: //上下顛倒
				map_x.at<float>(row, col) = col;
				map_y.at<float>(row, col) = src.rows - row - 1;
				break;
			case 3: //上下左右都顛倒
				map_x.at<float>(row, col) = src.cols - col - 1;
				map_y.at<float>(row, col) = src.rows - row - 1;
				break;
			}
		}
	}
}

縮小成一半：

左右顛倒：

上下顛倒：

上下左右都顛倒：