Because the texture and color the tongue and the lip is very close

it is difficult to extract the accurate contour of the tongue body only with the active contour model： Snake.This paper introduces a method that combines radial edge detection with Snakes model to solve this problem.Firstly

we use radial edge detection to get rough contour of the tongue.Then

we use pair-color-remove to remove the lip.Finally

we use snake to get the exact contour of the tongue. The experiment results are satisfying.