Design and fabrication of a cMUT probe for ultrasound imaging of fingerprints

Abstract

Optical fingerprint scanners suffer from limited depth of penetration and are particularly sensitive to the surface conditions of the skin. Fingerprint scanners based on ultrasounds offer the possibility to explore the surface and the underlying tissues of the finger and to detect blood flow, leading to enhanced robustness and reliability in biometric applications. Capacitive Micromachined Ultrasonic Transducers (cMUTs) have shown to have great potential for use in medical imaging applications. The ease of fabricating broadband high-frequency ultrasound transducers makes the cMUT technology a good candidate for ultrasound based biometrics. This paper presents the design, fabrication and characterization of a cMUT linear array probe optimized for near-field ultrasound imaging. Ultrasound images of fingerprints are obtained using a customized 3D ultrasound scanning system

3D Ultrasound palm vein pattern for biometric recognition

“…As concern the imaging analysis the same software exploited in previous work was exploited [6][7][8][9][10][11]. It can provide simultaneous B and C-scans of any part of the volume data and it is also able to operate 3D voxel grayscale intensity representations of the selected volume.…”

“…The authors has recently experimented this technique for the biometric recognition of hand geometry [6][7], palmprint [8][9] and fingerprint [9][10][11]. The data are acquired by the probe and stored in a series of B-scans that forms a 3D matrix representing a specific volume of the human hand.…”

Experimental Validation of a Reliable Palmprint Recognition System Based on 2D Ultrasound Images

“…The first research activities aiming to develop recognition systems that exploit ultrasound images of fingerprints date back to the end of the last century [8]. In the following years, several implementations of fingerprint ultrasound sensors have been experimented [9][10][11][12] and different types of ultrasonic fingerprint readers [13,14] are now produced and integrated in smartphone and tablet devices [15][16][17].…”

Pulse-echo ultrasonic fingerprint sensor on a chip

“…A recent result [2] based on a capacitive micromachined ultrasonic transducer (CMUT) 2D array eliminates the need of mechanical scanning, but the complex interface between the large sensor array and the signal-processing electronics fails to meet the size target. Short-range imaging has been demonstrated using piezoelectric micromachined ultrasonic transducer (PMUT) arrays [3], but without integrated electronics, individual read-out of the PMUTs in an array is daunting.…”