如何使用Opencv 2.3从灰度图像更改像素值？

Question

When i read a grayscaled image using for example in Opencv 2.3:

Mat src = imread("44.png" ,0);

How can i access the pixel value of it?

I know if its RGB i can use:

std::cout << src.at<cv::Vec3b>(i,j)[0].

Thanks in advance.

Answer 1

Since a grayscale image contains only one component instead of 3, the resulting matrix/image is of type CV_8UC1 instead of CV_8UC3 . And this in turn means, that individual pixels are not 3-vectors of bytes ( cv::Vec3b ) but just single bytes ( unsigned char or OpenCV's uchar ). So you can just use:

src.at<unsigned char>(i, j)