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How My Images Are Dithered

dead.garden

31–40 of 81 posts

Re: How My Images Are Dithered

#32
post #17

Speaking of which, are there any good ways to undither images? Things like GIMP FFT are not perfectly reversible.

It's a somewhat active inverse problems research subfield https://github.com/MenghanXia/ReversibleHalftoning

That one does not seem to be an undither project, it appears to be a special way to encode chroma information within a monochrome dithered image. NTSC television also encodes chroma within a grayscale signal, but that's different than black and white only.

Re: How My Images Are Dithered

#33

Why is this not a typical data augmentation method for training deep networks? It would allow the networks to learn invariants that's align with humans. Currently, I suppose none of these dithered images would be correctly classified.

When someone says AI can't do something, I like to try it:

> This image features a close-up abstract scene styled with a classic halftone (Ben-Day dot) pop-art filter ...

https://share.gemini.google/O5eqZOKxwzw3

> This image is a halftone/thermal print styled photograph. The photo features a group of four people posing closely together indoors or in front of a windowed backdrop:

https://share.gemini.google/KJOxBDXYsFT4

Re: How My Images Are Dithered

#38

Every image should be dithered below 10 bits/component to prevent banding artifacts.

The counterpoint is that you should just keep your images at 10 bit minimum or 12+ bit until the OS/monitor can dither for you. Lossy compression will do much better with a 10/12 bit image than a dithered 8 bit one.

Re: How My Images Are Dithered

#40
post #29

Earlier quoted context omitted.

Yeah. But even if you stay in the digital realm, dithering is necessary at 8bits per component. Consider that a grayscale gradient can only have 256 distinct levels.

True! You’re less likely to be surprised by banding on a display, because you can see it before it’s a problem, and it’s less likely to cost money, but for sure the need for dithering is still there, especially for displays that can do more than 8 bits per channel or can do high dynamic range. > Consider that a grayscale gradient can only have 256 distinct levels. This is true, but also keep in mind that for print an…

I think HDR wasn't what changed. It's resolution. At 720P and below, you don't notice dither because pixelation is the more obvious problem. Once you're at 1080p (and it's more obvious at 1440p/4k), you start having enough detail to see the banding patterns.
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