Show HN: High End Color Quantizer

#1

Post by big-nacho » Tue, Jun 10, 2025, 11:50 AM UTC

This is a personal project I've been working on for a long time now.

I stumbled upon the color quantization problem while doing something related for work. I then found an interesting paper for which I could find no implementations online, and the thing went from "let's implement this paper" to getting pretty obsessed with the whole thing.

It's at an early, eaaaarly stage. There's a lot of work to be done, and it's a memory hog, but generally speaking works quite well, and the output is for the most part very high quality, so I'm happy to share it as beta.

Show HN: High End Color Quantizer
github.com

Re: Show HN: High End Color Quantizer

#2

Post by andrelaszlo » Tue, Jun 10, 2025, 12:45 PM UTC

[flagged]

Re: Show HN: High End Color Quantizer

#3

Post by [deleted] » Tue, Jun 10, 2025, 12:50 PM UTC

andrelaszlo wrote: post #2

[flagged]

[deleted]

Re: Show HN: High End Color Quantizer

#4

Post by leeoniya » Tue, Jun 10, 2025, 1:10 PM UTC

Wu v2 is really good. i said it in 2015 :)

https://news.ycombinator.com/item?id=9213955

see that whole thread, too

Re: Show HN: High End Color Quantizer

#5

Post by pinoy420 » Tue, Jun 10, 2025, 1:11 PM UTC

[dead]

Re: Show HN: High End Color Quantizer

#6

Post by ansgri » Tue, Jun 10, 2025, 1:13 PM UTC

What's the primary use case you had in mind here? In the example I see it generating a palette of 256 colors and then using them, but it doesn't seem to correspond to any modern use case. AFAIU one currently needs dithering either as part of print/display process (but then you have a fixed palette), or for compression, but I think this makes sense nowadays only with very low color count, like 16 max?

Re: Show HN: High End Color Quantizer

#7

Post by dinfinity » Tue, Jun 10, 2025, 1:13 PM UTC

The example image only shows the differences between parts of the image that are deemed as salient, but does not show the effects of the tradeoff on the non-salient parts nor does it show an entire quantized image.

I'd say that showing full example results are the most important part of showcasing a "high end" color quantizer.

Re: Show HN: High End Color Quantizer

#8

Post by pk-protect-ai » Tue, Jun 10, 2025, 1:15 PM UTC

I looked for pytorch native implementation for Xiaolin Wu's quantizer like 3 month ago, and found none. Would not it be much easier and more productive to integrate with pytorch? Some of the functionality which you have there is already provided by kornia, torch_kmeans. You'll end up with much less code to worry about.

Re: Show HN: High End Color Quantizer

#9

Post by big-nacho » Tue, Jun 10, 2025, 1:18 PM UTC

leeoniya wrote: post #4

Wu v2 is really good. i said it in 2015 :) https://news.ycombinator.com/item?id=9213955 see that whole thread, too

Will take a look, thanks for sharing! This does not implement Wu v2 but a different method he published a year later though.

Re: Show HN: High End Color Quantizer

#10

Post by pk-protect-ai » Tue, Jun 10, 2025, 1:19 PM UTC

ansgri wrote: post #6

What's the primary use case you had in mind here? In the example I see it generating a palette of 256 colors and then using them, but it doesn't seem to correspond to any modern use case. AFAIU one currently needs dithering either as part of print/display process (but then you have a fixed palette), or for compression, but I think this makes sense nowadays only with very low color count, like 16 max?

Oh, there are still several use cases to consider. It is still related to compression pretty much and there some niche non-obvious use cases for this quantization.