Tuesday, August 21, 2012

New filters for KStars FITSViewer

In preparation for my first astrophotography trial using 100% Linux based software, I added a couple of important filters to KStars FITSViewer tool. The first filter Equalize performs histogram equalization which enhances the contrast of an image. The filter works quite well with images of diffuse continuous flux such as nebulae or galaxies. For star fields, the filter actually significantly raises the background noise level, and stars become buried within the noise. Here is an example of applying the Equalize filter to M42. As you can see, the contrast of the image is greatly enhanced.

M42 before Equalize filter
M42 after Equalize filter
The second filter is a simple low pass filter that brings out the details of an image without adding too much noise. The filter calculates a cutoff point in the image histogram, and rescales the image after chopping off the high flux pixels. The filter is demonstrated in the example below:

Star field before Low Filter Pass

Star field after Low Filter Pass


2 comments:

eBoy said...

So when this is going to merge with the KStars branch :D?? WANT!! :D

Jasem Mutlaq said...

It's already available in git repo, and should be 'officially' released for KDE 4.10! :-)