ImageLevels

ImageLevels[image] gives a list of pixel values and counts for each channel in image.

ImageLevels[image,bspec] bins pixel values using bin specification bspec.

ImageLevels[image,bspec,range] gives counts for bins in the given range.

Examples

Get pixel value counts:

ImageLevels[ExampleData[{"TestImage", "Lena"}]]

Please visit the official Wolfram Language Reference for more details.