Font Size: a A A

The Theoretical And Experimental Study On Palm Vein Recognition Technology

Posted on:2011-06-12Degree:DoctorType:Dissertation
Country:ChinaCandidate:Q LiFull Text:PDF
GTID:1118360305492193Subject:Optical Engineering
Abstract/Summary:PDF Full Text Request
Hand vein recognition is the technology that the vast network of blood vessels is taken as the pattern for recognition. The vein pattern is hard to fake as the vein is under a person's skin. Therefore, the vein recognition is a potentially good biometric. In recently years, most hand vein recognition researchers focus on the vein of the back of hand and finger vein because the vein image of these parts is easy to capture. The palm vein is suitable for biometric as it contains a lot of blood vessels. However, to our knowledge, there is no domestic institute and company has carried out research on palm vein pattern biometric recognition technology. In this paper, a new personal recognition system using vein patterns in the palm side of the hand is proposed. The research includes image acquisition, image preprocessing, and pattern recognition.(1) Because of no publicly available palm vein pattern database for research community, we design our own near infrared palm vein image acquisition system in order to utilize palm vein pattern for recognition. In this system, we use an array of LEDs which emit the infrared light at a wavelength of 850nm to shine infrared light onto the palm side of the hand. At the same side, an IR CCD camera whose spectral response also peaks at a wavelength of around 850nm is used to obtain the image of the palm vein. To dissipate the effect of visible light, an IR filter is mounted in front of the camera's lens.(2) A short-focus len is used to acquire the palm vein image of view in wide field. However, there is generally nonlinear geometric distortion to some extent as the imaging of object point in the image plane is compared with the ideal imaging. A method of digital image geometry correction based on neural network and automatic generation of reference points has been proposed in this paper. The experiment results indicate that the reference points can be settled quickly and readily with the algorithm of automated generation of reference points. Moreover, neural network fits the distortion model which reaches a high precision. In a word, the method put forward in the paper possesses commendable capability in correcting the geometry distortion of image.(3) In the image pre-processing stage, the research includes the ROI extraction, image normalization, image contrast enhancement, and image denoising. Linear stretching algorithm, histogram equalization algorithm and CLAHE algorithm are used to enhance the image. Curvelets are very good at representing objects with curve-punctuated smoothness. In this paper, the curvelet transform algorithm is proposed for the imag denoising. This algorithm can effectively eliminatie noise compared to other method.(4) In the recognition section, four algorithms are used in this paper:PCA method, wavelet energy algorithm, curvelet energy algorithm, curvelet transform based on PCA algorithm. In recognition mode, Using PCA method, the recognition rate (CRR) is 99.4%, but PCA is not suitable identification mode. Wavelet energy algorithm can obtain images at different resolutions, different directions of the distribution. We use the energy of Haar wavelet transform of the image as vein pattern for identification and recognition, CRR reached 98.8% and EER is 2.6%. Compared with the wavelet transform, curvelet transform has good representation of curve. We use the energy of curvelet transform of the image as vein pattern for identification and recognition, CRR reached 99% and EER is 2.1%. The curvelet transform based on PCA algorithm is used for recognition, and get CRR of 99.6%.In this thesis, a new personal recognition system using palm vein patterns is proposed. This system is convenient to acquire vein images compare to those base on vein pattern of the back of the hand. Using those recognition algothm we proposed in this paper, the palm vein recognition system has excellent performance.
Keywords/Search Tags:Biometric, Palm vein, Geometric distortion, PCA, Wavelet transform, Curvelet transform
PDF Full Text Request
Related items