【摘要】 根据介质阻挡放电的原理,建立了介质阻挡放电人体指纹图像的提取装置.采用静态指纹提取方法,比较了3种不同厚度(0 1mm、0 2mm、0 3mm)介质层时指纹图像的清晰度.结果表明,随着介质层厚度的增加,放电空间的电场趋于均匀,导致指纹放电强度在空间均匀化,从而使指纹成像的分辨率下降.利用动态指纹提取方法观察到了手指在介质层表面产生的沿面放电现象.实验中观察到,金属圆柱体和长方体之间表面放电的长度是有限的,从而证实发生在纹脊之间的沿面放电并不会对图像分辨率产生较大的影响.研究结果表明,为提高指纹图像的清晰度,采用较薄的介质,使用纳秒脉冲放电技术降低沿面放电的程度,是十分必要的.更多还原

【Abstract】 Based on the principle of dielectric barrier discharge photography, the equipment of the human’s fingerprint acquisition is developed. Three photos of the fingerprint discharge image are obtained by static state method in cases of the dielectric film thickness of 01 mm, 02 mm and 03 mm respectively. The result shows that with the increase of thickness of the dielectric film, the discharge gap electric field intension trends uniformly, and the fingerprint discharge intension then distributes uniformly in space, which results in a weakened fingerprint image definition. The phenomenon of fingerprint discharge along the dielectric film surface is observed by dynamic method. The limited surface discharge length between a metallic cylinder and a metallic cuboid block is observed experimentally, thus it is confirmed that surface discharge among fingerprint ridges does not influence on the definition of fingerprint image actually. As a conclusion, it is necessary to use thinner film for improving the definition and to adopt nanosecond pulse discharge technique for restraining the surface discharge.更多还原