opencv使用split函数进行通道的分离，merge进行通道的合并
可以使用channels求出图像的通道数，示例如下：
ROI提取感兴趣的区域
1 #include <opencv2/opencv.hpp> 2 #include <iostream> 3 4 using namespace cv; 5 using namespace std; 6 7 int main(int argc, char** argv) { 8 Mat src = imread("D:/images/test5.png"); 9 if (src.empty()) { 10 printf("could not find image file"); 11 return -1; 12 } 13 namedWindow("input", WINDOW_AUTOSIZE); 14 15 vector<Mat> mv; 16 split(src, mv); 17 int size = mv.size(); 18 printf("number of channels : %d \n", size); 19 imshow("blue channel", mv[0]); 20 imshow("green channel", mv[1]); 21 imshow("red channel", mv[2]); 22 bitwise_not(mv[0], mv[0]); 23 Mat dst; 24 merge(mv, dst); 25 imshow("result", dst); 26 27 // ROI 28 Rect roi; 29 roi.x = 100; 30 roi.y = 100; 31 roi.width = 250; 32 roi.height = 200; 33 Mat sub = src(roi).clone(); 34 bitwise_not(sub, sub); 35 rectangle(src, roi, Scalar(255, 255, 0), 1, 8); 36 imshow("roi", sub); 37 imshow("input", src); 38 waitKey(0); 39 destroyAllWindows(); 40 return 0; 41 }
结果如下：
