Research Of OCT-Based Finger Subcutaneous Fingerprint Image Acquisition Method

With the development of social information technology,the information security and personal security have become the focus issues that the country is increasingly concerned about.As an important means to ensure information security and personal safety,identity authentication has been widely used in our daily life.However,these applications are facing the problem of low recognition rate and weak anti-counterfeiting ability under the big crowd.Because of the uniqueness and unforgeability,biometrics have gained more and more attention in the field of identity authentication.Among them,fingerprints have become the most widely used biometric features because of their uniqueness,permanence,and convenience of collection.However,the traditional fingerprints are vulnerable to external conditions such as wet skin and damaged skin will affect the recognition success rate.and the forge defects of traditional fingerprints are unable to meet the requirements of modern people for identification already.The subcutaneous fingerprint is located inside the human skin and has the advantages of high accuracy,difficulty in counterfeiting,and non-breakage.The optical coherence tomography(OCT)technique can obtain the subcutaneous fingerprint of the human fingertip,which solves the problem of weak anti-counterfeiting and low recognition rate in traditional fingerprint recognition.After analyzing the optical coherence tomography technology,finger biometrics,and Zynq chip architecture,this paper presents an OCT-based finger subcutaneous fingerprint image acquisition method,and designs a Zynq-based OCT data acquisition system and OCT imaging algorithm processing and calculation unit.The designed system was verified and analyzed.The results show that the system can obtain accurate fingerprints.The main work of the thesis is as follows.(1)Subcutaneous fingerprint data collection and storage: After studying the mathematical principle of OCT,we discussed the acquisition of subcutaneous fingerprint acquisition methods,and chose to use Zynq chip as the main chip of the system,using the internal PL part to achieve hardware timing design,complete the OCT spectrum Data collection.Through AXI_HP interface,we designed a DMA IP core based on AXI4 bus,which can directly store image data in memory,solve the problem of insufficient memory resources encountered in traditional FPGA,and complete the high-speed storage of spectral data.(2)Zynq-based frequency-domain OCT imaging algorithm: After analyzing the frequency domain OCT imaging algorithm flow,we designed a Zynq-based frequency domain OCT imaging algorithm unit.In this algorithm unit,a fast-handover floating-point divider,interpolation multiplier,and FFT calculation unit are designed to perform fast frequency domain OCT imaging.(3)Acquisition device system debugging and acquisition experiment: According to the previous design of the OCT-based subcutaneous fingerprint acquisition system,build a collection platform for debugging and experimentation.Completed the CCD camera driver debugging,data storage module verification and imaging algorithm unit analysis.In the laboratory,the real human finger and silicone fingerprint sleeve were used for image acquisition experiments.Visual analysis was performed on the collected images.Subcutaneous fingerprints and epidermis fingerprints were observed to verify the reliability and effectiveness of the system.