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Re: [APML] LMC & SMC
>Could you tell us whether/how this DBE deals with the combination of
>multiplicative (vignetting) and additive (sky gradient) effects, while
>steering clear of solutions which tend to locally harm the astronomical
>objects themselves? I'm very interested in the algorithmic approach taken.
Hi Ray
DBE doesn't correct the image for any gradient. What you do with it is in simple words to put a lot of sample boxes to measure the sky brightness in every channel, and then interpolate a two dimensional function between the samples. Then, you generate a new image with the "illumination profile", or more preciscely, the background or sky of the image. Later, using PixelMath you can substract, divide, or do whatever you want. You might think of it just as a tool to create pseudo-flats, or a way to get only the sky with every feature removed.
I think that a suitable solution for you problem is just the "divide and conquer" strategy. First, deal with all the predictable effects: i.e. vigneting, atmospheric extintion, etc. Almost all of them are multiplicative effects (don't?). If you get a nonuniform sky, probably it is becouse of additive effects that we ussually can't derive theorically. Here we can make use of sky substraction as a way to deal with them.
What happens if we don't have flats, or there is another mixed effect...? I don't know <vbg>
Regards,
Carlos Milovic F.
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