External And Internal Fingerprint Extraction Method Based On Optical Coherence Tomography

With increasing security requirement of individual identity authentication,biometric identification technologies have developed rapidly.With various biometric,fingerprint has been used most widely because of its uniqueness,permanence,and convenience of collection.However,when the fingertips are stained with water or dust,or fake fingerprints are used,the traditional fingerprint biometric identification system will have problems such as false rejection or false acceptance.It has been found biologically that the fingerprint pattern of the human body also presents in the nipple layer inside the fingertip.The internal fingerprint is the source of external fingerprint and can be used as a substitute for external fingerprint without external interference.The internal biological structure of the fingertip can be clearly obtained by an optical coherence tomography(OCT)imaging technique.Thus,the external interference robustness and anti-counterfeiting capabilities of the fingerprint can be improved.After the study of OCT system and fingerprint acquisition,we find out that the commercially available OCT system usually has limited acquisition area which is not enough for fingerprints.Meanwhile,existing fingerprint extraction methods require numerous parameters and some with pre-knowledge.To solve these problems,this paper proposes an adaptive OCT-based external and internal fingerprints extraction method.The main contributions of this paper are summarized as follows:(1)OCT data acquisition and image preprocessing: The OCT system is improved to realize large-area high-resolution acquisition of fingertip data.A variety of denoising algorithms are compared and the Block-Matching 3D(BM3D)algorithm is adapted to remove the speckle noise in OCT images as a preparation for subsequent fingerprint extraction.(2)Adaptive extraction methods for external and internal fingerprint: by analyzing the OCT image distributions and the internal structure of the fingertips,this paper proposes a hierarchical clustering based adaptive segmentation method with weighted similarity distance metrics and adaptive termination thresholds to extract the contours of the stratum corneum and papillary junction.After internal and external fingerprints are reformed,the multi-scale Retinex(MSR)algorithm is further adapted to enhance the fingerprint images and improve the contrast of the generated fingerprint images.(3)Experimental analysis and comparison: The fingerprints extracted from the OCT and that from a traditional acquisition system are compared.The consistency of the internal and external fingerprint is verified.Experiments are also carried out on external interference and fingerprint forgery,which prove that the internal fingerprint has good inter ference immunity and anti-counterfeiting capabilities.This paper implements an external fingerprint and internal fingerprint extraction method based on OCT technology,and proves the effectiveness,recognizability and anti-counterfeiting effect of OCT fingerprinting through experiments.