imagemagick 

Applies a Dragan-like effect to an image to enhance wrinkles creating a "gritty" effect.

Automatically thresholds an image to binary (b/w) format using an adaptive spatial subdivision color reduction technique. This is the -colors IM operator as implemented with slight modification from Anthony's... More information

Processses a scanned document of text to clean the text background and enhance the text.

Processses a picture of a whiteboard with writing on it to clean up the background and correct the perspective. The four corners of the actual interior of the whiteboard in the picture must be supplied in order... More information