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Proceedings Paper

Object detection system using SPAD proximity detectors
Author(s): Laurence Stark; Jeffrey M. Raynor; Robert K. Henderson
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Paper Abstract

This paper presents an object detection system based upon the use of multiple single photon avalanche diode (SPAD) proximity sensors operating upon the time-of-flight (ToF) principle, whereby the co-ordinates of a target object in a coordinate system relative to the assembly are calculated. The system is similar to a touch screen system in form and operation except that the lack of requirement of a physical sensing surface provides a novel advantage over most existing touch screen technologies. The sensors are controlled by FPGA-based firmware and each proximity sensor in the system measures the range from the sensor to the target object. A software algorithm is implemented to calculate the x-y coordinates of the target object based on the distance measurements from at least two separate sensors and the known relative positions of these sensors. Existing proximity sensors were capable of determining the distance to an object with centimetric accuracy and were modified to obtain a wide field of view in the x-y axes with low beam angle in z in order to provide a detection area as large as possible. Design and implementation of the firmware, electronic hardware, mechanics and optics are covered in the paper. Possible future work would include characterisation with alternative designs of proximity sensors, as this is the component which determines the highest achievable accur1acy of the system.

Paper Details

Date Published: 22 September 2011
PDF: 12 pages
Proc. SPIE 8167, Optical Design and Engineering IV, 81672A (22 September 2011); doi: 10.1117/12.896860
Show Author Affiliations
Laurence Stark, STMicroelectronics Ltd. (United Kingdom)
The Univ. of Edinburgh (United Kingdom)
Jeffrey M. Raynor, STMicroelectronics Ltd. (United Kingdom)
Robert K. Henderson, The Univ. of Edinburgh (United Kingdom)

Published in SPIE Proceedings Vol. 8167:
Optical Design and Engineering IV
Jean-Luc M. Tissot; Laurent Mazuray; Rolf Wartmann; Jeffrey M. Raynor; Andrew Wood, Editor(s)

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