Function imageproc::utils::pixel_diff_summary

pub fn pixel_diff_summary<I, J, P>(actual: &I, expected: &J) -> Option<String> where
    P: Pixel + PartialEq,
    P::Subpixel: Debug,
    I: GenericImage<Pixel = P>,
    J: GenericImage<Pixel = P>, 

Human readable description of some of the pixels that differ between left and right, or None if all pixels match.