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Error Analysis of Combined Optical-Flow and Stereo Passive RangingThe motion of an imaging sensor causes each imaged point of the seem to describe a time trajectory on the image plane. The trajectories of all imaged points are reminiscent of a flow (eg, of liquid) which is the source of the term "optical flow". Optical-flow ranging is a method by which the stream of two-dimensional images obtained from a forward-looking forward-moving passive sensor is used to compute range to points in the field of view. Another well-known ranging method consists of triangulation based on stereo images obtained from at least two stationary sensors. In this paper we analyze the potential accuracies of a combined optical flow and stereo passive-ranging system in the context of helicopter nap-of-the-earth obstacle avoidance. The Cramer-Rao lower bound (CRLB) is developed for the combined system under the assumption of a random angular misalignment common to both cameras of a stereo pair. It is shown that the range accuracy degradations caused by misalignment is negligible for a combined optical-flow and stereo system as compared with a monocular optical-flow system.
Document ID
20000023181
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Barniv, Yair
(NASA Ames Research Center Moffett Field, CA United States)
Date Acquired
August 19, 2013
Publication Date
October 1, 1992
Publication Information
Publication: IEEE Transactions on Aerospace and Electronic Systems
Publisher: Institute of Electrical and Electronics Engineers
Volume: 28
Issue: 4
ISSN: 0018-9251
Subject Category
Optics
Report/Patent Number
IEEE-LN-9202245
Distribution Limits
Public
Copyright
Other

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