Author Topic: Arcsinhstretch vs Histogram Transformation  (Read 367 times)

Offline dpaul

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Arcsinhstretch vs Histogram Transformation
« on: 2018 March 02 19:46:03 »
Just wanted to share my first attempt at reprocessing the same data of M99. The one that has more 'blue' was using Arcsinhstretch and Multiscale Linear Transform for noise reduction. The other was using Histogram Transformation and TVG Denoise.

In general the arcsinhstretch was processed as follows:

1/. Integrated R,G,B and L were separately deconvoluted, noise reduction then MT for star reduction - all using a galaxy mask (inverted and non-inverted) and a star mask.
2/. Combined R,G, and B into an RGB image using channel combination
3/. Background neutralised the RGB image, color calibrated it and used DBE (with a galaxy inverted mask)
4/. Combined the RGB image and L image by dropping the L onto the RGB using LRGB Combination
5/. Final bit of tweaking the saturation and background darkness using curves (with a galaxy mask, inverted and non inverted

I'm still a novice but just to show the same data can be processed better. I found the MLT easier to use for background noise reduction than TVGdenoise and less chance of a bad result. Also arcsinhstretch seems to give better colors than histogram stretch.

Don't know if I did things in the right order but I'm reasonably happy with the result.

(all images taken with Atik Horizon, 30'' Lockwood optics dobsonian, F3.5)