High resolution ultrasonic method for 3D fingerprint recognizable characteristics in biometrics identification

Biometrics is currently a very rapidly evolving scientific and applied discipline, which studies the different possible ways of personal identification by means of certain unique biological characteristics of each individual. Such identification is very important in various situations requiring restricted access to certain areas, information, personal data, and in cases of medical emergencies. A number of automated biometric techniques have been developed, including fingerprint, hand shape, eye and facial recognition, thermographic imaging, etc. All of these techniques differ in the recognizable parameters, usability, accuracy and cost. Among others, fingerprint recognition stands alone - because a very large database of fingerprints has already been acquired (for historical reasons). Also, fingerprints are usually the main evidence left at a crime scene and can be used to track down criminals. Therefore, of all the automated biometric techniques, especially in the field of law enforcement, fingerprint identification seems to be the most promising. This paper introduces a newer development of the ultrasonic fingerprint imaging. The proposed method allowed a scan to be obtained just once and then to vary the C-scan gate position and width to visualize acoustic reflections from any appropriate depth inside the skin. Also, B-scans and A-scans can be recreated from any position using such a data array. Therefore, this gives total control over the visualization options. By setting the C-scan gate deeper inside the skin, distribution of the sweat pores (which are located along the ridges) can be easily visualized. Given that this distribution should be unique for each individual, this provides additional means of personal identification, which is not affected by any changes (accidental or intentional) of the fingers´ surface conditions. This paper also gives thorough discussion of different setups, acoustic parameters of the system, signal and image processing options an- - d possible ways of 3-dimentional visualization that could be used as a recognizable characteristic in biometric identification.