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I've got a JPEG image with text on it (badly scanned document), which is hardly readable. I have already played around with the sharpen filters, contrast, levels and the color replacement tool, with decent success.

My question is, what else can be done in order to maximize the texts readability? The picture is also somewhat noisy.

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migrated from Jun 17 '10 at 2:06

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are you trying to read it programatically, or just trying to make it legible for human eyes? – Nathan Fellman Jun 17 '10 at 5:38

Sometimes "Convolution filter" with appropriate coefficients may help. It can blur a bit or sharpen a bit image in a flexible way.

You can also do "High Pass" filter (or duplicate layer, Gaussian blur it, set opacity to 50%, invert and merge) prior to adjusting levels and contrast.

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Sharpen filters, contrast, levels, and the color replacement tool are about the best you're gonna get.

There's no special 'black magic' tool to do this sort of thing because it can't be done. With raster graphics if the image is pixellated beyond recognition and there's no source image of higher quailty available there's not much you can do.

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