Image binarization and edge tracing are some old school image technologies.
Just played with them in as3 when I was trying to create a cartoon filter for flash.
Those techs are pixel level transformations, get/setPixel and get/setPixel32 can do that job,
it works slow, though.
The result,
original image:
Binarized image:
Edge:
Nothing new here. But if you need it, here are the codes:
