Garbz
04-09-2013, 05:58 PM
Hey guys, When I processed my M27 photo the other night I thought I'd try something and recorded a video of the processing. Not sure what I was thinking at the time but maybe this will help me learn from my mistakes or learn what works etc.
The resulting M27 picture is here: http://www.flickr.com/photos/10090242@N03/9671462468/
Anyway I thought I'd share the process I went through to make it incase it helps someone. Video is hopefully embedded below.
http://www.youtube.com/watch?v=trR5g3riAk8
Look a few posts below for another video it produced much better results.
The steps I went through are thus:
Opened single sub and debeyered.
Stacked all the subs together.
Compared the stacked image to the original single sub. I did this because I recently found that when I stuff up the stack it will actually add noise so comparing the noise in both images is a sanity check that the stacking worked well.
Basic crop applied, and image mirrored.
DBE used to eliminate background colours.
Histogram transform was applied to brighten up the image. Here I entered the median of each channel in the midrange and then entered 0.92 as the RGB/K midrange. This normally gives me a good starting point.
Next change the RGB working space to all 1s (apparently this helps some of the tools like ACDNR)
I extract the lightness channel and then use LRGB Recombination to add saturation to the image and do some colour noise reduction. I find this works better for overall saturation than the curves tool.
Use Dynamic PSF to determine the point spread function for deconvolution.
Build a star mask that I will use for a few tools.
Then I try in vain to get a decent deconvolution working but throw my arms up in frustration and settle for another way of sharpening the image.
I create another mask for all bright objects.
I move to ATrouseWaveletTransform and use it to sharpen the image by controlling the bias.
SCNR is applied though not really needed as there wasn't much of a green tinge in this image.
Then I move to ACDNR to reduce lightness noise.
I prepared another mask that was blurry but focused only on the nebula itself.
Again I used ATrouseWaveletTransform to sharpen the image, this time with a different set of parameters to make the nebula "pop" a bit more.
Still not quite poppy enough I also used LocalHistogramEqualisation to add a very subtle HDR effect. I'm not a fan of overuse of the effect so by the time I'm finished with the settings the result is quite subtle.
Finally a bit of playing with curves to get the background down in brightness and then I add a bit of saturation to the blue stars.
A quick rescale and I posted it on the web.
I wonder if anyone will find this helpful.
The resulting M27 picture is here: http://www.flickr.com/photos/10090242@N03/9671462468/
Anyway I thought I'd share the process I went through to make it incase it helps someone. Video is hopefully embedded below.
http://www.youtube.com/watch?v=trR5g3riAk8
Look a few posts below for another video it produced much better results.
The steps I went through are thus:
Opened single sub and debeyered.
Stacked all the subs together.
Compared the stacked image to the original single sub. I did this because I recently found that when I stuff up the stack it will actually add noise so comparing the noise in both images is a sanity check that the stacking worked well.
Basic crop applied, and image mirrored.
DBE used to eliminate background colours.
Histogram transform was applied to brighten up the image. Here I entered the median of each channel in the midrange and then entered 0.92 as the RGB/K midrange. This normally gives me a good starting point.
Next change the RGB working space to all 1s (apparently this helps some of the tools like ACDNR)
I extract the lightness channel and then use LRGB Recombination to add saturation to the image and do some colour noise reduction. I find this works better for overall saturation than the curves tool.
Use Dynamic PSF to determine the point spread function for deconvolution.
Build a star mask that I will use for a few tools.
Then I try in vain to get a decent deconvolution working but throw my arms up in frustration and settle for another way of sharpening the image.
I create another mask for all bright objects.
I move to ATrouseWaveletTransform and use it to sharpen the image by controlling the bias.
SCNR is applied though not really needed as there wasn't much of a green tinge in this image.
Then I move to ACDNR to reduce lightness noise.
I prepared another mask that was blurry but focused only on the nebula itself.
Again I used ATrouseWaveletTransform to sharpen the image, this time with a different set of parameters to make the nebula "pop" a bit more.
Still not quite poppy enough I also used LocalHistogramEqualisation to add a very subtle HDR effect. I'm not a fan of overuse of the effect so by the time I'm finished with the settings the result is quite subtle.
Finally a bit of playing with curves to get the background down in brightness and then I add a bit of saturation to the blue stars.
A quick rescale and I posted it on the web.
I wonder if anyone will find this helpful.