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Hi Gary and Wade,
Thank you very much for your nice words and your
support; they mean a lot and encourage me to continue with this
adventure.
The last question about removing faint objects by
applying incorrect background models is of great importance. As Carlos has
pointed out, when DBE samples are located over faint
objects, by subtracting the generated background model, the faint objects will
be damaged. This is especially true when no smoothing is used, since a
pure interpolating surface is applied, and the generated model will reproduce
the incorrect samples exactly.
When smoothing is used, the generated model is
not adjusted to contain all the sample values. Think of the DBE-generated
background model as a thin, elastic surface. The smoothing parameter works
by trying to flatten the surface, so small local variations are averaged.
Too high of a smoothing value, however, will yield an inaccurate model that will
be useless. When dealing with complex DBE targets, fine-tuning the smoothing
parameter is usually necessary.
The iterative approach that Carlos has described is
an elegant and efficient solution. It was devised and first used by Wei-Hao
Wang when we were developing DBE. Wei-Hao applied the iterative method to one of
his film images of the Witch Head region, and he was able to reveal
extremely dim emission nebulae around the reflection nebula. I should write a
tutorial with this material, if only I could find the time...
Let us know if you try it; we are very interested
in knowing your results.
Juan. |
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