Problem 682. Image Processing 002 : Fix Vignetting in a Visible Sensor

The task is to correct image files for Visible scanning sensors that due to errant tolerancing produce vignetted(V) images. The V artifact is in a converging ray bundle and only the edges are impacted to differing amounts. The obscuration varies cross-scan but is constant for all samples. Sensor package repair is cost prohibitive. Luckily, the Image Processing is Matlab based and needs only a fast function to perform the V adjustment good enough for govt work.

Output: Fixed image(Fimg) (Array <= 512x512 of type double)

Input: Vignetted Image file(Vimg) (double); Obscuration (1xncol)

Tolerance: Good enough is 1%+1 count of Truth (Timg)

Obscuration: Max is 25% at edge, Min 8 columns wide.

Vignetted Image creation: Start with Truth (Timg)

Vimg = Timg(1-Obscuration)

example: Obs = [.25 .1 0...0 .1 .25]; obs [50 20 0...0 20 50];

load penny.mat; Timg=double(P);

Vimg=Timg.*repmat(1-Obs,128,1)

The Cody "Image processing 001" for an IR and using In-scene data was not intended to be so complex. This and its successor should have appeared prior to "001".

This Visible Vignetting correction is very direct.