In this paper, skin detection, texture filtering and face detection are used to extract feature on an image library, training
them with the decision tree arithmetic to create some rules as a decision tree classifier to distinguish an unknown image.
Experiment based on more than twenty thousand images, the precision rate can get 76.21% when testing on 13025
pornographic images and elapsed time is less than 0.2s. This experiment shows it has a good popularity. Among the steps
mentioned above, proposing a new skin detection model which called irregular polygon region skin detection model based
on YCbCr color space. This skin detection model can lower the false detection rate on skin detection. A new method called
sequence region labeling on binary connected area can calculate features on connected area, it is faster and needs less
memory than other recursive methods.