Detecting hair in a portrait image?

Question

What would be the best approach for detecting and removing a person's hair in a simple portrait image ? Any useful libraries of algorithms ? I have been looking over openCV which looks like it could be of some use

Answer 1

I think this is hard problem - consider for detecting and removing hair in this case:

I found several papers, maybe they will help you:

• Detection and analysis of hair
• Dullrazor®: A software approach to hair removal from images
• Research on the Expression of Hair in Computer Animation

Cheers!

Answer 2

You're dealing with two different problems here:

1. detecting if a face in a portrait has hair
2. "removing" the hair

The first is solvable fairly easily:

• Separate the face from the background (as you've mentioned a "simple portrait image", this shouldn't be too hard).
• Convert your image to the Y'CbCr color space
• Human skin has a fairly narrow range of chrominance values, regardless of race. Check out this paper for the details.
• The approach above will help you separate skin areas of the face from non-skin areas
• Assume that the non-skin areas consist of hair. Note that facial hair will get picked up as a non-skin area, too.

As far as the second problem goes, you need to clarify exactly what you mean by "removing":

• Are you simply cutting out the part of the portrait that has hair? In this case, the solution follows directly from the detection method above.
• Are you trying to make it look like the person has no hair at all (e.g. is bald, clean-shaven?) In this case, things will be a lot harder -- there's a reason why professional photo manipulators get paid well.