Vignetting, discussion about methods of resolution Options

[Tman]

Hi Nirgal and all, I would like to discuss about vignetting and methods of resolution for it. I'm mainly interested in mathematical methods that could automatically calculate and adjust the right grey value for each pixel in a single picture.

My current method works with more or less transparent layers over the original picture that so roughly are able to balance the grey values. A perfect layer have to be the exact inverted brightness difference of each picture with this shadow effects. This method is very effective if you get the correct inverted values. These shots of the Mars sky come nearly at such a perfect mask, but not always. And of course the center of the pictures lose much of theirs original brightness/luminance sadly.

I have in mind a mathematical method that can adjust each grey value in a pic in order to obtain a completely balanced brightness over the entire picture. But I'm not in the position to reach that. I only know one have to start with the calculation of the grey values in the center of the picture. In the center are quasi the reference values of the whole picture, if I'm correct.
Is there a possibility (mathematical method) to get (roughly) the same brightness and luminance like in the center over the whole picture from the MERs?

Greetings, Peter

[edstrick]

Dark current images are those taken with zero exposure. They actually are of two types.. Ones taken with zero exposure, and ones taken with time exposure of a zero-brightness scene, then read out at slower than the maximum possible speed. As a camera's detector "sits" before readout, it accumulates (or a vidicon looses) charge, and the blank image changes with exposure time and readout settings.

A flat-field image is one taken of a uniformly illuminated scene, to calibrate for camera and lens response variations AFTER a perfectly matched dark image is subtracted. You then divide data images by the flat-field to get hopefully clean decalibrated images.