ASinH stretch?

[akulapanam]

I came across a thread on another forum showing the power that ASinH stretching has to preserve star color and I was curious how to write a pixel math expression to mimic the that type of stretch.

[aworonow]

read all the way through...https://pixinsight.com/forum/index.php?topic=418.0

Alex

[akulapanam]

Thanks,  It maybe a "simplistic solution" and I haven't tried it so it may not even work really well.  On the other hand I find it hard to generate the really deep star colors that StarTools and it seems like maybe Iris (haven't used it) can generate.  I even have taken to masking the stars and saturating them separately with the curves tool, using repair HSV separation, and masked stretch.  Yet I throw it in a different program and I get deeper colors with the same data.

[akulapanam]

I suppose part of this might not be the stretch but rather the LRGB combination method.  Perhaps a different method of combining Luminance with RGB vs. the LRGB process or replacing L in the LAB color space might help.

[sharkmelley]

I came across a thread on another forum showing the power that ASinH stretching has to preserve star color and I was curious how to write a pixel math expression to mimic the that type of stretch.

Try here:
http://www.cloudynights.com/topic/569440-pixinsight-arcsinh-stretch/