This simple script will take a picture of a whiteboard and use parts of the ImageMagick library with sane defaults to clean it up tremendously.

whiteboard.sh

#!/bin/bash
convert "$1" -resize %50 -morphology Convolve DoG:15,100,0 -negate -normalize -blur 0x1 -channel RBG -level 60%,91%,0.1 "$2"


# source: http://www.reddit.com/r/commandline/comments/1weqnn/cli_oneliner_script_to_clean_up_and_beautify/