Ringing with PI's Masked Stretch

[Garbz]

I'm really digging masked stretch for the smooth results it gives when going from the linear to the non-linear stage of image processing however I've run into issues trying this on M42.

The centre of the bright stars are hard clipped on my M42 and this results in ringing using masked stretch even when iterations has been increased to 1000. I've tried a few different masks which all result in moving the ringing around the star but none have so far managed to eliminate it.

Does anyone know how I can prevent ringing of clipped areas?
Alternatively does anyone know how I can repair it post masked stretch?

[h0ughy]

there is a video on the HDR process on the PI website that addresses this issue i think http://harrysastroshed.com/pixinsight/pixinsight%20video%20html/pixinsighthomeinter.html

[troypiggo]

Might need to post examples of before/after and raw files?

[Garbz]

Okay, here's a FITS file, cropped onto one of the stars in question.

http://www.garbz.com/dump/clipped_star.fit

I actually did come up with a workable solution to fix the stars afterwards. This revolved around masking an area larger than the clipped section of the star and then convolving. Kind of makes a mockery of my process though since I normally deconvolve :-)

[troypiggo]

Sometimes masked stretch leaves stars kind of a "plateau" with a disk of saturated (or near saturated). Can look odd, so mask the really brights and slight gauss blur experimenting brings them back to more appealing.

[RickS]

I rarely use MaskedStretch because I hate that, Chris! A mask and convolution is the best solution I've been able to come up with. Great minds?

Cheers,
Rick.

[peter_4059]

Chris,

Sounds like you've come up with an alternative to the PI delete FITS / download Hubble image script?

Peter

[Garbz]

Yes I am quite happy with the result. I mean the ideal case would have been to record some not clipped data too and do a HDR composition, but nothing like faking it a bit :)