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Characterization of modulated time-of-flight range image sensors

Abstract
A number of full field image sensors have been developed that are capable of simultaneously measuring intensity and distance (range) for every pixel in a given scene using an indirect time-of-flight measurement technique. A light source is intensity modulated at a frequency between 10–100 MHz, and an image sensor is modulated at the same frequency, synchronously sampling light reflected from objects in the scene (homodyne detection). The time of flight is manifested as a phase shift in the illumination modulation envelope, which can be determined from the sampled data simultaneously for each pixel in the scene. This paper presents a method of characterizing the high frequency modulation response of these image sensors, using a pico-second laser pulser. The characterization results allow the optimal operating parameters, such as the modulation frequency, to be identified in order to maximize the range measurement precision for a given sensor. A number of potential sources of error exist when using these sensors, including deficiencies in the modulation waveform shape, duty cycle, or phase, resulting in contamination of the resultant range data. From the characterization data these parameters can be identified and compensated for by modifying the sensor hardware or through post processing of the acquired range measurements.
Type
Conference Contribution
Type of thesis
Series
Citation
Andrew D. Payne, Adrian A. Dorrington, Michael J. Cree and Dale A. Carnegie, "Characterization of modulated time-of-flight range image sensors," Three-Dimensional Imaging Metrology, J. Angelo Beraldin, Geraldine S. Cheok, Michael McCarthy, Ulrich Neuschaefer-Rube, Editors, Proc. SPIE, 7239, 723904 (2009).
Date
2009
Publisher
SPIE and IS&T
Degree
Supervisors
Rights
Copyright 2009 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.