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I try to make Unpaper to work, it's a very powerfull tool to post-process scanned book pages. I read the Doc but still can't make it work neither on Windows nor on Linux. My picture is a Bitmap I converted to .pbm format with Gimp (also tried pgm and pnm). Then I use this command:

unpaper -l double --pre-rotate -90 inputFile.pbm outputFile.pbm

(-l double means I have 2 pages in one sheet and --pre-rotate -90 turns the image to the left)

It should do something like this:

enter image description here

But my output file has no differences between the input, just rotated.

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migrated from Jul 29 '11 at 12:03

This question came from our site for professional and enthusiast programmers.

I finally found out the issue. The problem was the conversion to the .pbm format done by Gimp (v2.6.11). The converted file was not binary (only white or black pixels) whereas Wikipedia says "PBM is for bitmaps (black and white, no grays)". So I used ImageMagick for the conversion and now unpaper works perfectly fine and I have excellent results with tesseract 3.

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