||Robust Optical Fingerprint Sensor to the Moisture Fingerprint
|| Optical fingerprint sensor; Moisture finger; NIST quality map; Extract fingerprint
||Optical technology is the most common sensor technology currently used in fingerprint recognition. Because the optical type of sensor has excellent durability and stability, it is used for many people to authenticate. On the other hand, semiconductor-type sensors are suitable for personal authentication, such as smartphones. This study examined ways to improve the problem of optical sensors, i.e., the difficulty in extracting the fingerprint minutiae via binarization, and determine the difference between the ridge and valley of a fingerprint when there is a lot of water or sweat on the fingerprint surface. Therefore, the structure of the prism was designed to distinguish between sweat and water. SF4 material with a minor influence of the refractive index was applied.
In addition, spherical lenses, G1 and G2, were designed and implemented to correct the trapezoidal distortion and reduce cost. To demonstrate the superiority of the study results, the image quality map of NIST and the minutiae distribution were compared using fingerprint recognition technology. The results showed that the proposed sensor has a high NFIQ quality score in all normal and moisture fingerprints.