指静脉采集设备的设计与实现

摘  要

随着信息技术在人们的日常生活、工作中扮演着越来越重要的角色，发挥着愈加显著的作用，信息社会对于系统及个人信息安全性的要求日益增加，实时身份认证系统相应的在现代生活中被提出，从而促进了生物特征识别技术的发展。而指静脉识别技术相对于其他技术来说，具有不可伪造、特征唯一、非接触采集等优点，引起了广大研究者的兴趣。

本文在阐述对指静脉识别技术国内外发展现状以及基本认证原理的基础之外，对指静脉采集系统设备进行了设计和实现。该系统的总体框图，主要由指静脉图像采集模块和PC机图像处理显示模块组成。其中指静脉图像采集模块用于拍摄识别过程需要的手指静脉图像，并通过网络通信实时传输到PC端来实现进一步的处理；PC机图像处理显示模块负责图像数据的接收，图片格式的转换、显示以及自动调焦的功能。本文基于OV7725 COMS图像传感器进行视频采集，以JZ4775做处理器，通过UDP通信实时显示到PC端，使用Python脚本编写上位机软件并对数据进行编码还原为BMP文件储存到PC端，同时实现了自动调焦功能。通过该指静脉采集系统的设计与实现，我们可以得到清晰的指静脉图像，为身份认证技术后续的特征提取和特征匹配工作提供了有效而可靠的数据。

关键词 ：指静脉识别 图像采集 自动调焦 OV7725 驱动开发

The Design and Implementation of the Vein Collection Equipment

ABSTRACT

With the information technology playing a more and more important role and having an increasingly significant impact in people's daily life, the requirements of the security of both system and personal information are increasing all the time in the information society, meanwhile the corresponding real time identity authentication system is put forward in the modern life, so as to promote the development of biometric identification technology. Compared with other techniques, the vein recognition technology has the advantages of non forgery, unique features and non contact acquisition, which has attracted the interest of researchers.

On the basis of the development status and the basic authentication principle of finger vein recognition technology, this paper designs and realizes the device of finger vein collection system. The overall block diagram of the system is mainly composed of the finger vein image acquisition module and the PC image process and display module. Which refers to the vein image acquisition module is used for getting the finger vein image for the identification process, and using the network communication to achieve the real-time transmission and the further image processing; PC display image process and display module is responsible for receiving the image data, converting the image format , displaying the image and automatic focusing function. The system is based on the OV7725 COMS image sensor for video capture, using JZ4775 processor, through the UDP communication real-time displaying the image on the PC, using the python to script host computer software and to encode data reduction for BMP file which is stored in the PC side. At the same time, the system realize the automatic focusing function. Through the design and implementation of the system, we can get a clear image of the finger vein lines, which provides a reliable and effective original data for the later feature matching process of the computer.

KEY WORDS:   Finger vein recognition  Image acquisition  Auto focus          OV7725  Driver development