Legacy ImageMagick Discussions Archive

I am a begginer in image processing, and a begginer with the library imagemagick. While I do have some experience, I wanted to ask what is channel distortion in image processing.
taken from the imagemagick website, in the "compare" command section:

In addition to the visual interpretation of the difference in an image and its reconstruction, we report a mathematical measure of the difference:

-> magick compare -verbose -metric mae rose.jpg reconstruct.jpg difference.png
Image: rose.jpg
Channel distortion: MAE
red: 2282.91 (0.034835)
green: 1853.99 (0.0282901)
blue: 2008.67 (0.0306503)
all: 1536.39 (0.0234439)

I don't understand what is the red, green, blue and 'all' distprtion represent. Can someone explain it to me ?

"Distortion" is another word for "difference". The number in parentheses eg (0.034835) tells us how much difference there is: 0.0 means no difference, 1.0 means totally different.

"-metric MAE" (see http://www.imagemagick.org/script/comma ... php#metric) calculates the mean of the absolute differences of pixel values. It calculates this for individual RGB channels, and for all the channels together.