Flatfield Image Generation Options

[antonio19812]

Anyone can help me suggesting me how to process the raw images from the VMC of Mars Express? I am working with them in Python, and I managed to get both the raw unfiltered and the RGB images, but only in the raw version. I am doing it without using the exsisting tools. I have not a deep knowledge about this topic and I would like to have some hints about it. Anyone has some interesting link or can suggest some person that could help me?

[Gerald]

Are you talking about a flat field image or a flat-fielded image?
Once you have a flat-field, devide the raw image by the flat-field (requires floating point arithmetics, with a subsequent stretch over the available brightness range).
If you don't have a flat-field, in some cases sky images are available. Average over some of them, and use this average as a flat-field.
If no sky images or laboratory flat fields are available, things get more complicated. You could then try to infer a flat-field from overlapping images, but that's beyond what I can tell out-of-the-hip.

[antonio19812]

Are you talking about a flat field image or a flat-fielded image?
Once you have a flat-field, devide the raw image by the flat-field (requires floating point arithmetics, with a subsequent stretch over the available brightness range).
If you don't have a flat-field, in some cases sky images are available. Average over some of them, and use this average as a flat-field.
If no sky images or laboratory flat fields are available, things get more complicated. You could then try to infer a flat-field from overlapping images, but that's beyond what I can tell out-of-the-hip.

Probably you gave me a good hint.
Actually I need to extract a flat filed , to obtain then the flat-fielded images. Yes, a set of sky images are available. Is there any more accurate algorithm to extract a flat-field image besided the averaging approach? I am searching for some more elements but with no results