Application of lidar techniques to time-of-flight range imaging
Whyte, R., Streeter, L., Cree, M. J., & Dorrington, A. A. (2015). Application of lidar techniques to time-of-flight range imaging. Applied Optics, 54(33), 9654–9664. https://doi.org/10.1364/AO.54.009654
Permanent Research Commons link: https://hdl.handle.net/10289/11419
Amplitude modulated continuous wave (AMCW) time-of flight (ToF) range imaging cameras measure distance by illuminating the scene with amplitude modulated light and measuring the phase difference between the transmitted and reflected modulation envelope. This method of optical range measurement suffers from errors caused by multiple propagation paths, motion, phase wrapping and non-ideal amplitude modulation. In this paper a ToF camera is modified to operate in modes analogous to continuous wave (CW) and stepped frequency continuous wave (SFCW) lidar. In CW operation the velocity of objects can be measured. CW measurement of velocity was linear with true velocity (R² = 0.9969). Qualitative analysis of a complex scene confirms that range measured by SFCW is resilient to errors caused by multiple propagation paths, phase wrapping and non-ideal amplitude modulation which plague AMCW operation. In viewing a complicated scene through a translucent sheet, quantitative comparison of AMCW with SFCW demonstrated a reduction in the median error from −1.3 m to −0.06 m with inter-quartile range of error reduced from 4.0 m to 0.18 m.
OPTICAL SOC AMER
This is an author’s accepted version of an article published in the journal: Applied Optics. © 2015 Optical Society of America.