The recognition of the teeth marks of tongue based on the improved level set in TCM

The recognition of the teeth marks on tongue pays an important role for automatic tongue diagnosis in Traditional Chinese Medicine. If the teeth marks are not obvious, it is difficult to recognize the teeth marks on tongue desirably with some popular methods directly. In order to overcome this difficulty, a method that bases improved level set method, curvature and image gradient is presented. First, the tongue boundary line is initialized in the HSV color space and a method which enhances the contrast between tongue and other parts of the tongue image is introduced. Second, a new region-based signed pressure force function is proposed, which can efficiently stop the line at weak edges. Third, we use a Gaussian filtering process to further regularize the level set function instead of reinitializing signed distance function. Finally, we propose a method which recognize the teeth marks with both line curvature and image gradient. Experiments by numerous real tongue images show desirable performances of our method.