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