Research On Acquisition And Encryption Of Finger Vein Image

As a new biometric recognition technology,finger vein recognition is developing rapidly with its unique characteristics of living recognition and detection of human internal features,means that it has wide application prospects.In this paper,acquisition and encryption of finger vein image are studied.The main contents are as follows:(1)To capture high-quality finger vein images,an acquisition system is designed and manufactured in this paper.The system consists of three parts,namely,a light source control module for controlling the intensity of three independent infrared LEDs,an imaging module for image formation of the finger vein,which is realized by a MT9V034 image sensor,and a human-computer interaction module for image acquisition.In the third module,the upper computer controls the slave computer,whose master chip is CY7C68013.(2)An adaptive illumination control algorithm is presented to solve the problem of uneven gray in the finger vein image.After the finger vein image is obtained,the edge robustness detection and the rotation alignment are employed,and then the positions and gray values of the two interphalangeal joints are obtained.According to the collection requirements,the adjustment command is issued by the host computer and the brightness of the NIR LED is adjusted.When the adaptive adjustment of the light source is completed,a finger vein image with uniform gray value is obtained.(3)An efficient image encryption algorithm based on hyper-chaos and a global bit cycle shift(HC-GBCS)is proposed.First,we use a four-dimensional hyper-chaotic system to generate a pseudorandom sequence.The SHA-256 secure hash algorithm is presented in our encryption scheme and we then use both pixel-level and bit-level permutation to enhance the security of the encryption system.Finally,to change the pixel values,two rounds of diffusion operation are employed to finish the whole encryption procedures.Simulation results show that the algorithm encrypts both ordinary gray images and finger vein images effectively and achieves high security and stability.