unpaper example

unpaper.sh

# folder repository
# ./                      #<-- destination folder
# ./originals/any.pdf     #<-- any number of pdfs to convert, originals
# ./originals/unpaper.sh  #<-- this script

# inspired from https://gist.github.com/legumbre/1182280/60c3bfc13b9d89b57fef733f67ad60de2624be6a
set -x
for i in *.pdf; do
	gs -q -dNOPAUSE -dBATCH -sDEVICE=ppmraw -sOutputFile=%04d.ppm "$i"
	for f in *.ppm; do
    # adjust brightness (20) and contrast (10) to preprocess for unpaper
		convert "$f" -brightness-contrast 20x10 -colorspace Gray -grayscale average "${f%.ppm}.bright.ppm"
	done
	unpaper --layout single %04d.bright.ppm unpaper%04d.ppm
	echo you may need to rm ../"$i"
	convert unpaper*.ppm ../"$i"
	open output.pdf
	echo 'you may want to clean with rm *.ppm'
done