3D Skeleton Reconstruction Of Finger Vein Based On Biplane Angiograms

Finger vein recognition has shown great advantages and reliability in biometric recognition.At present,most of the researches on finger vein recognition are based on two-dimensional projections of finger veins.Because the finger vein is a three-dimensional reticular structure,different finger veins may have the same or similar two-dimensional projections.Therefore,the finger vein recognition based on two-dimensional images may lead to the recognition error.To solve the error identification,this thesis focuses on the three-dimensional skeleton reconstruction of the finger vein.Because the three-dimensional skeleton of finger vein has the merits of topological stability and uniqueness.In this thesis,three-dimensional skeleton reconstruction of finger vein is studied.A image acquisition system based on biplane angiograms is designed and a method of three-dimensional skeleton reconstruction of finger vein is proposed.The three-dimensional skeleton reconstruction of finger vein includes image acquisition from two angles,image preprocessing,feature point detection and matching,coordinate transformation.matching of finger vein skeleton,and three-dimensional reconstruction.The specific studies are as follows:(1)According to the imaging characteristics of the finger vein,this thesis selects the appropriate light source and imaging equipment,and then designs the acquisition system based on biplane angiograms.It ensures the commonness of the finger-vein images from different angles.(2)Two finger vein skeletons are obtained after image preprocessing.According to the characteristics of pixels in the neighborhood of feature points on two finger vein skeletons,automatic recognition of feature points is completed.And then the topological characteristic of finger vein skeletons is used to automatically match feature points.(3)In view of the one-to-many matching of pixels on the corresponding finger vein skeleton segments,an adaptive linear stretching method is proposed in this study.This method makes the corresponding finger vein skeleton segments have the same length in the same pixel coordinate system.Combined with the piecewise polynomial curve fitting method of least square method,the points on two finger vein skeletons with different angles are matched one by one,and the curve fitting error is calculated.(4)The complete 3D finger vein skeleton is reconstructed,and the factors affecting the 3D reconstruction result are analyzed.Through this study,a method for three-dimensional reconstruction of finger vein skeleton is established.A three-dimensional finger vein skeleton is established according to the two-dimensional gray images.The experimental result shows that the proposed method can reduce the difficulty of acquiring two-dimensional finger vein images.and the reconstructed curve of three-dimensional finger vein skeleton is relatively smooth.