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Differentiable Dithering

peterstefek.me

11–20 of 51 posts

Re: Differentiable Dithering

#11

> A pipedream would be an entirely differentiable image compression pipeline where all the steps can be fine tuned together to optimize a particular image with respect to any differentiable loss function. Neural Image Compression? https://arxiv.org/abs/1908.08988

I fear that you might end up with hallucinations in your images ...

Re: Differentiable Dithering

#12
Looks cool!

Two questions:

- Is this approach also learning the palette? It is kind presented as a given here but it is of course very important for a good dithering.

- The loss function might work better on spatially downsampled images. The downsampling causes a mix of the image colors making the dithered image look more like the original given a good dithering. This also naturally removes the variance that is now penalized in the loss function as this is blurred away.

Re: Differentiable Dithering

#13
Very interesting!

This seems somewhat similar to the recently published GIFnets[1]. However, I believe GIFnets is training a reusable network to a predict palettes, and pixel assignments, while this post is focusing on optimising the "weights" (i.e. pixel values) for a single image.

I wonder if the loss functions from GIFnets could be applied to this single-image approach to potentially solve the banding problem via something a little more "perceptual" than the variance term mentioned.

[1]: "GIFnets: Differentiable GIF Encoding Framework" https://arxiv.org/abs/2006.13434

Re: Differentiable Dithering

#14
post #11

> A pipedream would be an entirely differentiable image compression pipeline where all the steps can be fine tuned together to optimize a particular image with respect to any differentiable loss function. Neural Image Compression? https://arxiv.org/abs/1908.08988

I fear that you might end up with hallucinations in your images ...

Isn't that a feature?

Re: Differentiable Dithering

#15
post #11

> A pipedream would be an entirely differentiable image compression pipeline where all the steps can be fine tuned together to optimize a particular image with respect to any differentiable loss function. Neural Image Compression? https://arxiv.org/abs/1908.08988

I fear that you might end up with hallucinations in your images ...

Similar to imagining Ryan Gosling is in your background https://petapixel.com/2020/08/17/gigapixel-ai-accidentally-a...

Re: Differentiable Dithering

#17

> A pipedream would be an entirely differentiable image compression pipeline where all the steps can be fine tuned together to optimize a particular image with respect to any differentiable loss function. Neural Image Compression? https://arxiv.org/abs/1908.08988

Unfortunately you wouldn't have any guarantees on the output of any particular image though, just some reassurances about the expected behaviour over the training set.

Re: Differentiable Dithering

#18
post #15
post #11

Earlier quoted context omitted.

I fear that you might end up with hallucinations in your images ...

Similar to imagining Ryan Gosling is in your background https://petapixel.com/2020/08/17/gigapixel-ai-accidentally-a...

Ryan Gosling? That's quite a stretch.

Re: Differentiable Dithering

#19
A straightforward implementation of differentiable dithering consists in applying a large support band-pass filter to the image (so that it becomes of of zero-mean), and then thresholding it at 0. Sure, you lose the property that the average colors over large regions are conserved, but the image is perfectly recognizable, even with higher contrast than the original.
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