Do you lose information when processing images that have been grayscaled?

I have a comple double matrix and I mat2gray the matrix for registration. Am I losing information in terms of the image ? Should I instead apply translations that i find on the mat2grayed matrix to the original matrix?

Answer 1

[Matt J]

If you used this syntax

I = mat2gray(A,[amin amax]) 

with amin>min(A(:)) or amax<max(A(:)), then yes there will be information loss. All pixels above and below amin and amax get thresholded.