基于智能手机的多光谱指纹图像采集研究

为了解决现场指纹图像采集过程中指纹背景颜色复杂、导致对比度和采集效率较低的问题, 采用智能手机设计了便携式指纹图像采集装置。一方面将手机连接单片机, 电动切换不同波长光源, 获得多光谱图像; 另一方面自动采集不同光源下的指纹图像。为确保指纹图像质量满足后续识别需求, 采用多光谱融合及方向滤波技术对图像进行了增强处理。结果表明, 当光源数目为4时, 采集及处理时间低于1s, 满足现场采集需求; 装置能够有效采集指纹图像并融合增强。该装置具有低成本、自动化及便携性高的优点, 有望在刑侦领域取得广泛应用。

Acquisition of multi-spectrum fingerprint image with a smartphone

In order to overcome the problem that the image contrast and collection efficiency of on-site fingerprint images are usually quite low due to complicated background color at the crime scene, a portable fingerprint image acquisition system with a smartphone was proposed. In the system, a microprocessor connected to a smartphone through bluetooth can electrically switch light sources of different wavelengths. Multi-spectrum images were acquired to improve the fingerprint image contrast. With the help of the microprocessor, the smartphone can automatically capture fingerprint images under the illumination of different light sources. To ensure that the image quality can meet the requirements of identification process, the images were further enhanced by using multi-spectrum fusion and orientation filtering. Results show that the proposed system can effectively collect, fuse, and enhance multi-spectrum fingerprint images. It takes less than 1s to acquire and process the images when the number of light sources is 4, which satisfies the requirement of on-site image acquisition. As the system has the advantages of low cost, automation, and high portability, it is expected to be widely applied in criminal investigation.