Electrical and Computer Engineering ETDs

Publication Date

Spring 4-13-2023

Abstract

For space surveillance applications, neuromorphic imaging is being studied as it may perform sensing and tracking tasks with less power and downstream datalink demand. The read-out of the event-based camera is made to only be sensitive to changes in the signals it receives from the photodetector, which results in a datastream of events indicating where and when changes in illumination occur. This is in contrast to the conventional framing camera, which produces images by essentially counting the electrons produced by light incident on each pixel’s photodetector. These cameras are commercially available with siliconbased detectors for applications involving visible wavelengths. However, much more research is needed before the event-based read-out can be effectively used with smaller bandgap photodetectors to increase the utility of event-based sensing into the mid- and long-wavelength infrared.

The photoreceptor stage is the main part of the event-based read-out circuitry that interacts with the photodetector. To evaluate the performance and limitations of using pixel circuitry for longer wavelength infrared detection, DC and AC characterizations of the event-based sensor photoreceptor circuit are conducted as a function of mid-wave infrared detector parameters. Detailed analysis of the circuit provides insight into the sensitivity of the photodetector bias stability, the temperature-dependence of the dynamic range, practical constraints to the dynamic range that emerge with the use of longer-wavelength photodetectors, and bandwidth dependence on the input photodetector current. The purpose of this study is to develop a fundamental event-based sensing circuit that is tailored for mid-wave infrared photodetection. This will allow for the characterization of prototype mid-wave event-based sensors and enable the evaluation of which mid-wave infrared detector properties significantly impact the event-based sensor’s performance characteristics.

Keywords

Event-based sensors, EBS, Dynamic vision sensor, photoreceptor, subthreshold conduction

Document Type

Thesis

Language

English

Degree Name

Electrical Engineering

Level of Degree

Masters

Department Name

Electrical and Computer Engineering

First Committee Member (Chair)

Payman Zarkesh-Ha

Second Committee Member

Francesca Cavallo

Third Committee Member

Preston T. Webster

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