Light pollution rem...
 
Share:
Notifications
Clear all

Light pollution removal  

  RSS

(@rickwayne)
White Dwarf Customer
Joined: 2 years ago
Posts: 20
November 23, 2020 02:28  

So I watched Mabula's helpful tutorial on the light-pollution removal tool, and have been following that -- a few boxes, drawn in places that sort of looked like they might be helpful. I honestly had no idea how Mabula chose those particular spots and sizes, though -- I wish I could have eavesdropped on his internal monologue when he was doing so!

Today I was really struggling with some data that have admittedly awful gradients -- my fault, not light pollution's -- and happened to search for other tutorials. In this one, the author covers the entire screen (except for obvious nebulosity) with the selection boxes.  "It couldn't work that way, otherwise the software could just do it automatically", I thought.

Hah. A couple hundred box-draws later, my nightmarish image became tractable.

So. Huh. Couldn't the software assign boxes automatically? You could specify a box size with a slider or even just small/medium/large, and carpet the image with boxes. Then, instead of drawing boxes, you just click to remove the ones on nebulosity you don't want to lose, and perhaps draw in a few smaller ones manually.

I realize that we users can come up with features a lot faster than they could be implemented, but this one should be relatively simple to implement and would speed up the operation by a lot!


ReplyQuote
Topic Tags
(@vincent-mod)
Universe Admin
Joined: 4 years ago
Posts: 2885
November 23, 2020 11:25  
Posted by: @rickwayne

So I watched Mabula's helpful tutorial on the light-pollution removal tool, and have been following that -- a few boxes, drawn in places that sort of looked like they might be helpful. I honestly had no idea how Mabula chose those particular spots and sizes, though -- I wish I could have eavesdropped on his internal monologue when he was doing so!

I can understand that. So, it basically comes down to choosing an area where you think there is no nebulosity or halo from a bright star. You can more easily identify such area's by over saturating (Sat. to max and Sat th. to 0) and stretching a lot (using the preset to 30%). After applying the correction you can rearrange boxes if you think you misplaced them, at the moment this means removing them all first and then re applying. However you now do have a better corrected image to work with already. For problematic area's, like a much darker patch somewhere, you want some boxes to creep up on that area, not directly inside that dark patch. That should then gradually correct those area's as well.

So. Huh. Couldn't the software assign boxes automatically? You could specify a box size with a slider or even just small/medium/large, and carpet the image with boxes. Then, instead of drawing boxes, you just click to remove the ones on nebulosity you don't want to lose, and perhaps draw in a few smaller ones manually.

I realize that we users can come up with features a lot faster than they could be implemented, but this one should be relatively simple to implement and would speed up the operation by a lot!

That would be possible, but is kind of difficult for software to really know. Maybe it's something Mabula might add, but the idea behind the tool is that it produces a rigid model of the gradient, meaning misplacing a box here and there shouldn't have a huge influence which makes it a bit more forgiving. Having very nasty gradients all over the place is always a problem for any algorithm, then it really becomes a question if it wouldn't be faster (and better, quality wise) to retake the data if possible.


ReplyQuote
(@rickwayne)
White Dwarf Customer
Joined: 2 years ago
Posts: 20
December 3, 2020 20:56  

BTW I was looking at SiriL, pursuant to a Cloudy Nights post, and realized that its Background Extraction tool employs a user-interface model that might work very well for APP without a ton of programming. Basically it generates a set of boxes in a regular array. SiriL skips what it thinks is the nebulosity, but that's not even really needed -- if you could just quickly throw a bunch of boxes onscreen and then click to remove some, that would obviate most of the drudgery right there. Even better if you could select a group of boxes to eliminate, and of course better still if you did have the auto-sensing tech to do a first pass at elimination for you. (Best of all would be autosensing with some sort of live sensitivity slider that would add more boxes or eliminate them while you watch.)

Any of those options would reduce a pain point. Personally I really want APP to make a killing in the market because I think it's awesome. And while cool new features are important, in my 30-plus years as a software developer it's often making stuff easier for the user that really builds loyalty.


ReplyQuote
Share: