Optical flow image on QGC

Dear all,
I have a question about QGC showing optical flow image. I saw in the source code that the default format that is used to be presented on QGC is RAW8U. Could someone tell me what format this is ? As far as my concerned, this is a gray scale image format: using 0-255 as one byte to depict the gray scale, am I right?

That’s right. it is a grayscale image. a pixel is a byte.