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Research On Palm Vein Image Feature Extraction Theory And Algorithm

Posted on:2011-02-28Degree:MasterType:Thesis
Country:ChinaCandidate:C YangFull Text:PDF
GTID:2178330338478997Subject:Computer software and theory
Abstract/Summary:PDF Full Text Request
Biometrics is a hotspot of current authentication domain, research on it has already developed for many years in our home which takes the fingerprint recognition as symbol while research on the palm vein recognition is still in the initial stage, the palm vein recognition uses much more safety and reliable biological features-Palm Vein. it takes the human palm's vein blood vessel image as the processing data, then uses image pre-processing,feature extraction,pattern recognition methods to complete the authentication step.feature extraction is just one of the key technologies.This article conducted in-depth study of features extraction theory and methods in Palm Vein Recognition. The main work is as follows:First, it introduced palm vein recognition's technical route systematically, and elaborate told some key technologies, then introduce the important theoretical foundation which lies in texture feature extraction,shape structural feature extraction.Second, it had a thorough discussion about how to use Gabor transformation method to extract palm vein's textural property. In view of the higher dimension and its sensitivity to picture orientation in Gabor textural property extraction algorithm, this article proposed an improved Gabor feature coding method. this algorithm was on the basis of palm vein image's characteristic, such as subtracted the direct component in Gabor nuclear function to eliminate the influence of low frequency information to textural property extraction, extracted palm vein textural property through the suitable parameter selection; and uses improved positive and negative code and amplitude code algorithm to carry on unification coding of all characteristic in all direction, this reduce the characteristic dimension and enhanced the characteristic's robustness to picture orientation. Then we using AVR method to choose the best classified nature characteristic, which furthermore reduced the characteristic dimension and kept the original texture information in maximum limit.Third, the shape structural feature extraction method of palm vein has been thorough discussed. We pointed out that using feature point method lonely will lose the structure information of the palm vein. So we regard the vein blood vessel as a series of combination of curve segments, and use include angle chain method to describe the structure information of line segment, but it is limited to describe the outer contour and can do nothing for such graph that has lots of cross segments, as well as using the method of equal poly line in curve fitting will bring big fitting error in the place where the curve have the large scale change. In view of the above question, this article proposed one improved method to extract palm vein shape structural feature. In order to improve compute efficiency, we replace the first point of include angle chain with the extracted feature point; during curve fitting process, we use media value iteration method and let the error between fitting lines and original curve segments control the fitting process, Therefore, the accuracy of fitting can be infinitely close to the original curve segments, and the calculation can also greatly reduced while maintaining the superior characteristics that the include angle chain can greatly express the structural information among segments.Finally, In this paper, experiment has carried to validate the above algorithm, and comparative analysis has been taken with existing algorithms. Experiments results show that we have achieved the fast, robust feature extraction goal by improving the Gabor feature extraction algorithm and optimizing the include angle chain method, the speed and accuracy of feature extraction are improved, the sensibility of illumination change, displacement and rotation is overcome.
Keywords/Search Tags:Feature Extraction, Gabor Transform, Include Angle Chain, Texture Feature, Structural Feature
PDF Full Text Request
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