A row-column addressed acoustic biometric scanner integrated with pulse-oximetry
Abstract/Contents
- Abstract
- Biometric technologies are widely used for identification and liveness detection in several sectors including consumer electronics, governmental, healthcare, and banking. Fingerprint technologies account for approximately one third of the total biometric technologies market share, and their popularity is attributed to their cost-effectiveness, security, and ability to be integrated with other biometric technologies. There are three main types of fingerprint sensors: optical, capacitive, and ultrasonic. Compared to optical and capacitive sensors, ultrasonic sensors provide higher security as they can acquire volumetric images of the finger and perform better in the presence of contaminants. In order to reduce the effect of acoustic diffraction and achieve the required imaging resolution, current ultrasonic fingerprint sensors operate at either high or low frequencies. At low frequencies, they require acoustic waveguides which makes fabrication complex and expensive. At high frequencies, performance is limited by high acoustic attenuation. Additionally, current ultrasonic sensors use an opaque material stack which restricts their ability to be integrated with optical based liveness detection devices such as pulse oximetry. In this work, we propose the design of a simple 3-layer sensor consisting of a piezoelectric material layer sandwiched between two orthogonal electrode layers. This leads to a simple and cost-effective fabrication. By exploring trade-offs between operation frequency, aperture size, and signal-to-noise ratio, the sensor can achieve the required imaging resolution while operating in a moderate frequency range ([50-500] MHz). This leads to relatively low acoustic attenuation. Also, given the minimal material stack, the sensor can be semi-transparent. This dissertation describes the structure and operation of the sensor, and two imaging schemes (with and without ultrasonic focusing) to achieve the required imaging resolution. It presents the design and characterization of a sensor implementation tailored for consumer electronics and other devices that use glass platens. The dissertation also discusses the design and testing of an electronic imaging system that demonstrates the ultrasonic imaging capabilities of the sensor and its operation with pulse oximetry. In addition, it highlights the different image processing techniques used to enhance the fingerprint images. Finally, the dissertation presents another sensor implementation tailored for financial smart cards applications, and presents its imaging results
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2020; ©2020 |
| Publication date | 2020; 2020 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Touma, Gerard |
|---|---|
| Degree supervisor | Khuri-Yakub, Butrus T, 1948- |
| Thesis advisor | Khuri-Yakub, Butrus T, 1948- |
| Thesis advisor | Arbabian, Amin |
| Thesis advisor | Pauly, John |
| Degree committee member | Arbabian, Amin |
| Degree committee member | Pauly, John |
| Associated with | Stanford University, Department of Electrical Engineering. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Gerard Touma |
|---|---|
| Note | Submitted to the Department of Electrical Engineering |
| Thesis | Thesis Ph.D. Stanford University 2020 |
| Location | electronic resource |
Access conditions
- Copyright
- © 2020 by Gerard Touma
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