Research On High Resolution Palm Vein Acquisition And Pre-processing Methods

The applications of the identity authentication are applied not only in the public security and departments in counterterrorism, but also in daily life such as electronic payment. It is difficult to meet the demand of high accuracy and security by using traditional identification methods. With its unique advantages, palm vein has already become one of the focus issues. However, it is complicated to do the processing of palm vein image because of the difficulty of acquiring the palm vein image, the lacking of acquisition device, and the low quality of palm vein image. Therefore, the research is carried out on the access and preprocessing of high definition palm vein image and with its preprocessing, and a good foundation of further feature applications in this area is also laid.In this paper, based on the analysis of acquisition and preprocessing of palm vein, the image is combined with assessment method of image quality, and it is processed after. Finally the algorithm is applied to the palm vein image acquisition platform, which is developed independently. The contents and achievements of this paper are listed as follows:(1)Based on the comparative analysis of different assessment methods, by analyzing irradiation performance of light source, the acquisition image is assessed the quality by two-dimensional entropy with reference method that existing of gray level image quality assessment, of which the acceleration is suitable for hardware implementation. With the assessment results as feedback, the high definition images are finally obtained by controlling the intensity of the light source and the camera parameters adaptively. The results show that, this method has significant effect of enhancing the gray characteristic and vein feature.(2)Analyzing preprocessing method of palm vein image, with the image of high quality extract region of interest, the existing global image searching algorithms are improved. ROI is quickly scanned to capture in local area, and then operate with normalization, image denoising, enhancement, and segment skeleton of palm vein, finishing the all processes of palm vein at last. The experimental results show that the proposed ROI extraction method, has great advantages in constructing a fast discrimination and localization, and reducing the amount of computation of image obtained in the follow-up processing.(3)According to the method proposed in this paper, the palm vein acquisition system is finally finished in the embedded platform with a core of FPGA(Field Programmable Gate Array).