Pixel Joint Forum: Looking for an undithering tool

Message

   Hello, I'm sorry if this is not the place to ask, but it's the only one I could think of.

I'm looking for a software capable of undithering an image. I know there are a couple of algorithms out there that do it, but I have no programming background so I have no idea how to make them work.

The purpose is to enlarge a pixel art piece while trying to retain dithering. The piece was done with standard pattern dithering so the basic idea is to undither it, enlarge it using linear scaling and autodither it with the original palette. The piece is complex and large as it is (1900x1300 px, 24 colors) so redoing it is not an option.

Thanks

Author	Message
MIGUELbM Midshipman Joined: 07 June 2016 Online Status: Offline Posts: 20	Topic: Looking for an undithering tool Posted: 01 March 2017 at 5:28am
	Hello, I'm sorry if this is not the place to ask, but it's the only one I could think of. I'm looking for a software capable of undithering an image. I know there are a couple of algorithms out there that do it, but I have no programming background so I have no idea how to make them work. The purpose is to enlarge a pixel art piece while trying to retain dithering. The piece was done with standard pattern dithering so the basic idea is to undither it, enlarge it using linear scaling and autodither it with the original palette. The piece is complex and large as it is (1900x1300 px, 24 colors) so redoing it is not an option. Thanks
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Hapiel Rear Admiral Joined: 30 June 2023 Online Status: Offline Posts: 3266	Posted: 05 March 2017 at 8:12am
	Perhaps this trick would work for you: Scale down pixel art to 50% in non-indexed mode, so that the dithered areas blend into new colors. scale up 200% again to have the original size. Overlay this new image on top of the original image. Then, with a magic wand for example select the new non dithered areas and copy these to the original image. Would that work?
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DawnBringer Commander Joined: 11 August 2024 Online Status: Offline Posts: 568	Posted: 06 March 2017 at 9:09am
	Why do you need to enlarge an already huge image? And when you say "linear" scaling, do you mean bilinear or nearest neighbour?
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yrizoud Commander Joined: 03 May 2021 Location: France Online Status: Offline Posts: 343	Posted: 07 March 2017 at 5:37am
	Some time ago, bluedxca93 had similar needs, and we cobbled together a grafx2 script for this kind of operation. However it is designed for 16 color images, since it computes the 16x15 combinations of all dither patterns, and the result fits in 256-color format. http://pixeljoint.com/forum/forum_posts.asp?TID=17973
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