im2int8 - Convert image to 8-bit signed integers
im2int8 convert intensity or RGB images to 8-bit signed integers. If the input is of class int8, the output image is identical to it. Otherwise, im2int8 rescales or offsets the data, and returns the equivalent image of class int8.
im2bw, im2uint8, im2uint16, im2int16, im2int32, im2double, mat2gray,