Development of an image acquisition system for hand vein based on an embedded system

Abstract

As one kind of the latest forms of biometrics, the human hand vein recognition utilizes a state-of-the-art recognition algorithm based on unique veins and capillaries found on human dorsal hand, which possesses the advantages such as well anti-falsification and high noise immunity. For the hand vein recognition, the most important premise is acquiring the high quality hand vein image. According to the special effect of human hand vein on the near infrared (NIR), when a hand is scanned by an image sensor, the vein pattern appears darker than its surroundings. Depending on this characteristic, the NIR light source was utilized to illuminate the image acquisition system for hand vein. And the optimal parameters of light source were chosen and the light source with high uniformity illuminance was manufactured to acquire the more clear hand vein image. Simultaneously, for the purpose of system miniaturization and design flexibility, the embedded image acquisition system for hand vein was designed based on the technology of system on programmable chip (SOPC). FPGA and CMOS image sensor were taken as the core components in the system, and the hardware of acquisition module is realized by configuring NiosII soft-core CPU and some corresponding interface modules on a FPGA. The software was developed by using the NiosII IDE to realize the initialization control to CMOS image sensor and collection, storage and transmission for the image data gathered from CMOS. Then the collected hand vein image was simply preprocessed, which further improved the image quality. Through experiments, the results indicated that this system could obtain the hand vein image with high performance, and it supplied the embedded development platform for hand vein recognition simultaneously. It was significant to develop the hand vein recognition system with small size and high speed.