Commons:Deduster

Deduster is an (almost) lossless sensor dust spot removal program developed for Wikimedia Commons by User:Dschwen. Deduster clones out dust spots (which have to be manually selected) and replaces them with a best match texture taken from the neighborhood of the spot. This works very well for spots on uniform or gradient backgrounds like skies (where they are most apparent). Deduster preserves the exact DCT coefficient blocks of all unmodified regions and eliminates generational loss from lossy recompression of an already compressed JPEG image. This allows quality-preserving dust spot removal even if no RAW, TIFF, PNG original of the JPEG file is available.

The main component, the (almost) lossless spot removal code is finished. To deploy deduster on commons a Javascript interface for marking dustspots and a pywikipedia bot running on the toolserver, calling deduster periodically for newly marked images, are being developed.

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  Test image with an (artificial) sensor dust spot in the top center.
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  Intermediate output with the spot removed.
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  Per-pixel difference between the dusty original and the intermediate output (contrast increased for presentation purposes). Note that across the entire image pixel values have changed. This is generational compression loss and leads to quality degradation. This is suppressed in the final output.
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  Final output with the spot removed and the quality degradation suppressed.
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  Per-pixel difference between the dusty original and the final output. Note that the difference is exactly zero except where the spot was removed.