Wednesday, November 18, 2009

Sharpening photos like they do in CSI

There's a recurring joke on nerd hang-outs like reddit about the "enhanced photo" plot device on dramas like CSI: a grainy, low-resolution image is zoomed and sharpened to bring out impossibly small details -- finding the reflection of the killer in a distant chrome hub-cap, that sort of thing. It's obviously stupid.

But after playing around with The GIMP's "Wavelet enhance" filter, I'm really impressed -- it really seems to bring out fuzzy details:

(My best effort at cleaning the image up with contrast & brightness on the left; the wavlet-enhanced version on the right.) Clearly, it can't restore missing detail, but it seems to do a good job of improving the contrast around edges / features.

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