[Solved] Finding similar images but at different drawing stages

[Deleted member 1300963]

I've tried many duplicate image finders but there's one thing they all suck at : finding drawings at different stages of progress.

For example I downloaded BBCChan's work (thousands of drawings, this artist is really the GOAT btw) and there are images of the same drawing at different stages (sketch, line art, colorized) or with different coloration style (sepia, grayscale, full color) and the file names are messed up such that corresponding images don't have similar names, so finding them by eye is like the hardest and biggest game of memory where you never know if any image is alone or not and couples don't even look the same from afar so you're never sure if you are done.

So far I've used the following free programs and here's how they perform on this task according to my experience :

⚠ Just because a program performs bad at this task doesn't mean I don't generally recommend it. Some programs have advantages on different tasks, mainly because they handle sorting and grouping results or performing tasks on them differently.

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  ,
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  ,
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  and
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  :

Because the white background dominates a line art or sketch image, these programs find similarities between completely unrelated line art drawings long before connecting the same drawing in line art to its colorized version, so the image couples you're looking for are drowned in a long useless list. I went through 4600 image couples in Pixiple and found only a handful of correct associations.​

Here's an example of a bad and good connection with Pixiple :​

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As you can see from how far I am down the list ("Image Pair xx of xxx" at the top of the window) and the "Distance" value (lower value means more similarity), Pixiple found the bad couple very long before the good one.​

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  : finds a few connected drawings with different styles that the previous programs didn't but really only a few and there's no tolerance slider so you can't go further. Here's an example of a good connection it got which Pixiple did not detect :

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  and
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  : didn't find any similarity between drawings at different stages.
• I also tried this more recent
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  that was showcased in this
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  but as I suspected it gives no better results on this task and takes orders of magnitude longer to compute (GPU disabled).

If there's a better solution, I'd like to know.