Show HN: Clean up images damaged by noise / JPEGing. 100% in-browser

by jacobn • 8 years ago

6 4 8 years ago

jacobn• 8 years ago

Hi, I'm one of the authors of this tool, happy to answer any questions.

It's basically a little image processing algorithm for restoring rasterized vector art that's been degraded by various forms of abuse (noise, JPEG, print & scan), packaged up in a simple single-page application (sSPA? ;)

There's also a photo mode for de-blocking heavily JPEGed photos.

jrd792• 8 years ago

I'm the other developer. There is actually some pretty cool math behind this:

The underlying algorithm has not been published. At its core is a color median filter, a block-L1-minimizing generalization of the well-known scalar median filter. Applying such a filter to an image rounds out corners and destroys fine features, so a separate recovery step is needed. Filtered pixels that differ significantly from their original values are iteratively replaced with the distance-minimizing convex combination of neighboring filtered pixels, digging out corners and other destroyed features without re-introducing noise.

gitgud• 8 years ago

Cool, polished website. But if it does it 100% in the browser, then I expect to see the result in the browser. Maybe a [1] before/after slider would be a good addition.

[1] https://codepen.io/nosurprisethere/pen/xrXjYV

jrd792• 8 years ago

Just click the "View" button on each result and you get a full featured viewer with pan/zoom, quick toggling from before/after, and even a heat map showing where there are big differences between the two.

Show HN: Clean up images damaged by noise / JPEGing. 100% in-browser

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