How do I turn an image into a vector on the iPhone like Adobe Illustrator's Live Trace?

I want to be able to create vector files like Illustrator does on the iPhone. Does anyone know of an al开发者_如何学运维gorithm?

for each pixel try to grow by testing against it's neighbours for colour similarity with a threshhold. keep growing until no more expansion is possible due to threshold then you make a path using the outermost border pixels. Now repeat for the other pixels in the orignal raster image which were not already included in your previous expansions.