[textile]

US Patent number “6,751,348 B2”:http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=6751348 titled “Automated detection of pornographic images” was granted in June this year. I was looking to see if there is a working implementation to try out, but there seems to be none right now. Anyway, if it works as advertised, automatic network monitoring and parental control programs should work much better than now (blocking by domains).

Steps to determine if an image is porn:

# Compare each pixel’s color with library of skin colours (white/black/etc.)
# If it’s single pixel, it’s ok. If it’s an area of skin color, it’s probably skin.
# Using some algorithm to determine if it’s a face or not. If it’s just face, it’s probably portrait, which is ok.
# Determine from the shape which body part(s) is exposed.
# Determine if the post is erotic.

The picture above illustrate the calculation to determine if an area has the texture of skin, or just happen to be in that colour. Basically, if it’s _too smooth,_ it probably is _not_ skin.