Editor: RGBHIST displays a histogram of the overall Color Balance of an image.
Use the 'RGB' mode to get a quick sense of which colors are present in particular Highlight, shadow, and midtone regions. The 'LAB' mode is more useful for determining the actual color balance of an image, but it is slower.
This function supports UINT8, UINT16, INT8, INT16, and DOUBLE images without colormaps.
