Feature Acquisition And Analysis Of Sublingual Vein For Tongue Diagnosis In Traditional Chinese Medicine

Tongue diagnosis is one of the most common and valuable diagnostic method in Traditional Chinese Medicine. By means of the rapid development of digital image processing and pattern recognition technology, research on automatic tongue image acquisition and analysis can avoid the disadvantage of non-quantification and subjectivity in traditional tongue diagnosis, and make it widely acknowledged. Till now, research on feature extraction of tongue surface has been gradually perfect. However, research on one of the most important part of tongue diagnosis, the sublingual vein diagnosis, and its primary diagnosing indicator, the sublingual vein, is rarely referred by the researchers of this field.This dissertation takes the feature quantification method of sublingual vein in traditional Chinese medicine as the research centre, carrying out researches including the design of sublingual image acquisition device, segmentation of sublingual vein and feature quantification of sublingual vein, respectively.Acquiring sublingual image signal, which can effectively describe the feature of sublingual vein, is the basis of researching on the feature quantification of sublingual vein. This dissertation takes the diagnostic feature of sublingual vein in sublingual vein diagnosis into consideration. Firstly, from the viewpoint of acquiring the chromatic feature of sublingual vein, applying the color tongue image acquisition device to acquire the color sublingual image, and then preprocessing the acquired images. Meanwhile, whereas the limit of color sublingual image in describing the distance information feature of sublingual vein, combing with the vein recognition principle popularized in current Biometrics field, this dissertation systematically investigate the basic problem in near infrared sublingual image acquisition, such as the light source and sensor, etc., standardized acquisition strategy of near infrared sublingual image is formed. Finally, a novel near infrared sublingual image acquisition prototype is developed.And then, focus on the different contrast between sublingual vein and surrounding tongue proper in color sublingual images, this dissertation proposes the pixel-clustering-based region growing algorithm for segmentation of sublingual veins from color sublingual image with visible contrast between sublingual vein and surrounding tongue proper, and the adaptive sublingual vein segmentation method based on Bayesian decision theory for color sublingual image with low contrast between sublingual vein and surrounding tongue proper, respectively. Experimental results reveal that, the proposed methods possess acceptable performance on sublingual vein segmentation for color sublingual image with different condition of contrast between sublingual vein and surrounding tongue proper.The near infrared sublingual images acquired by using the portable near infrared sublingual vein image acquisition device designed in this dissertation, can more truly reflect the physiological contour of sublingual vein than the color sublingual images. Segmentation method of sublingual vein from the near infrared sublingual image is proposed in this dissertation according to the self characteristic of near infrared sublingual images, which establishes the foundation for quantifying the distance information feature of sublingual veins more precisely.From the aspect of extraction and quantification of the color feature of sublingual veins, this dissertation takes the judgment results to the color of sublingual veins from Chinese physicians as the basis, establishes the color description model of sublingual vein based on expert knowledge, furthermore, proposes the objective description of the color of sublingual vein which take the theory of tongue diagnosis into consideration; moreover, pixel level classification of the color of sublingual vein based on KNN algorithm is applied to realize the classification of sublingual vein color on the basis of the established color description model of sublingual vein. Experimental results reveal that, the classification result of sublingual vein color obtained from the proposed model and the corresponding classification method are close to that given by Chinese physicians.Considering the distance information of sublingual veins, measurement method of the length and width of sublingual veins, which both possess diagnostic value in tongue diagnosis, is proposed. And then, experiments are implemented to measure the distance information of the sublingual vein regions in two kinds of sublingual images, color sublingual image and near infrared sublingual image.This dissertation systematically researches on the acquisition of sublingual images, segmentation of sublingual veins and feature quantification of sublingual veins, which make applying multiple sublingual vein features with diagnostic value to assist diseases diagnosing in the research on modernization of TCM tongue diagnosis come true in future.