on Fingerprint Discharge Image
Weng Ming, Xu Weijun,Zheng Hua
(School of Electronics and Information Engineering, Xi'an Jiatotong University, Xi'an 710049, China)
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 01 mm, 02 mm and 03 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.
Keywords:fingerprint;dielectric barrier discharge;surface discharge