I use this code to enhance photographs or other image files taken from black and white text. Does great job for optical character recognition, printing and other purposes. This script is using ImageMagick to do the actual job.
#!/bin/bash mkdir "bw" for x in *.jpg ; do b=`basename $x .jpg` echo $x convert -noise 1 -unsharp 10x5+10 -threshold 20% "$x" "bw/$b.pbm"; unpaper "bw/$b.pbm" "bw/unpaper_$b.pbm" convert "bw/unpaper_$b.pbm" "bw/$b.png"; rm -f "bw/$b.pbm" "bw/unpaper_$b.pbm" done