Research Of Fingerprint And Finger-vein Image Integrated Acquisition System Based On Image Quality Evaluation

With a rising demand for information security,the biometric technology based on fingerprint and finger-vein has received extensive attention.To provide a more efficient image acquisition scheme and high-quality images of fingerprint and finger-vein for the fingerprint and finger-vein dual biometric identification,this article designs a fingerprint and finger-vein image integrated acquisition system using one camera and dual optical path,which also uses the evaluation algorithm of image quality to separate the images of fingerprint and finger-vein and evaluate their quality from multiple aspects.Firstly,this article introduces the research status of fingerprint and finger-vein image acquisition devices,then illustrates the adopted acquisition system with single CMOS and dual optical path,proceeding from acquisition of fingerprint and finger-vein.In terms of finger-vein image acquisition,this article applies the scheme of unilateral light source with mirror and optimizes the structure of LED array sources through the simulations of Tracepro and Solidworks to improve the illuminating uniformity of finger-vein's receives.In terms of fingerprint image acquisition,this article adopts a traditional optical acquisition scheme,using backlight and optical prism to transmit fingerprint's information to imaging unit.When it comes to the design for the integrated acquisition system,a single CMOS with dual optical path is employed to capture fingerprint and finger-vein image at the same time.Finally,the size of this system is 50mm*70mm*91.5mm after assembling,whose height is close to a 2nd-generation ID card's length.In order to evaluate the image from the acquisition device,this article proposes the image evaluation algorithm for the fingerprint and finger-vein image.With this algorithm,we divided the images of fingerprint and finger-vein from the original images,and evaluated these two kinds of images.Considering the problem during the image acquisition,this article evaluated the finger-vein image with consideration of image shifting,effective area,contrast ratio,ambiguity and entropy of information.For fingerprint image,this article evaluated it objectively from aspects of image shifting,effective area,ambiguity,dry fingerprint and wet fingerprint.At last,according to the typical image evaluation,it is obtained that the evaluation results match well to the subjective evaluation of common people,which means the proposed image evaluation algorithm can be well applied to these images.