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Processing Images of Craters for Spacecraft NavigationA crater-detection algorithm has been conceived to enable automation of what, heretofore, have been manual processes for utilizing images of craters on a celestial body as landmarks for navigating a spacecraft flying near or landing on that body. The images are acquired by an electronic camera aboard the spacecraft, then digitized, then processed by the algorithm, which consists mainly of the following steps: 1. Edges in an image detected and placed in a database. 2. Crater rim edges are selected from the edge database. 3. Edges that belong to the same crater are grouped together. 4. An ellipse is fitted to each group of crater edges. 5. Ellipses are refined directly in the image domain to reduce errors introduced in the detection of edges and fitting of ellipses. 6. The quality of each detected crater is evaluated. It is planned to utilize this algorithm as the basis of a computer program for automated, real-time, onboard processing of crater-image data. Experimental studies have led to the conclusion that this algorithm is capable of a detection rate >93 percent, a false-alarm rate <5 percent, a geometric error <0.5 pixel, and a position error <0.3 pixel.
Document ID
20090041760
Acquisition Source
Jet Propulsion Laboratory
Document Type
Other - NASA Tech Brief
Authors
Cheng, Yang
(California Inst. of Tech. Pasadena, CA, United States)
Johnson, Andrew E.
(California Inst. of Tech. Pasadena, CA, United States)
Matthies, Larry H.
(California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 24, 2013
Publication Date
December 1, 2009
Publication Information
Publication: NASA Tech Briefs, December 2009
Subject Category
Man/System Technology And Life Support
Report/Patent Number
NPO-40122
Distribution Limits
Public
Copyright
Public Use Permitted.
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