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Moisture effect of fingerprint using total internal reflection digital in-line holography
Author(s)
Plaipichit, Suwan
Date Issued
January 1, 2014
Type
Article
Abstract
Total internal reflection (TIR) is normally important in an optical fingerprint scanner. The moisture effect in a fingerprint scanner based on TIR has been explored by using digital in-line holography (DIH). First, the reflection and the transmission technique set up for DIH have been explored by using a positive resolution test target with a line width of 200 μm. From experimental results, the reconstructed image of the reflected DIH is perfect as the image of the transmitted DIH. Due to the advantage for opaque object imaging of the reflected DIH, reflected DIH based on TIR has been selected to investigate the moisture effect of the fingerprint. Fingerprints with moistures of 39%, 54%, 69%, and a soaked finger have been observed. A laser diode of 635 nm and a complementary metal oxide semiconductor camera were used in all of the experimental setups in this research. The reconstructed image of the fingerprint gives a sharper image than the directed recorded image. The fingerprint with higher moisture provided a darker fingerprint image, while the optimum amount of moisture that gives the most complete finger pattern is 54%. © 2014 Society of Photo-Optical Instrumentation Engineers.
Citation
Optical Engineering, 53(11), 2014