Relaxation method to lofargram
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Authors
Yang, Y.H.
Subjects
Relaxation method applied to lofargram
Advisors
Lee, C.H.
Date of Issue
1990-06
Date
1990-06
Publisher
Monterey, CA; Naval Postgraduate School
Language
Abstract
The term LOFAR is defined as 'search technique using omnidirectional sonobuoys'. It is an acronym for Low Frequency Analysis and Recording. When the signal to noise ratio is low, the detection of a track in a lofargram by computer is difficult. Actually, operators often face this kind of problem when detecting an acoustic signature in the noisy sea environment. Furthermore, operators must keep on tracking lofargram to identify a given target. This problem could be handled by the automation of lofargram processing using filtering or image processing techniques. This technique will suppress the background and emphasize the spectral lines in the lofargram. Targets can be tracked by an automatic lofargram processing system up to a certain point at which the system should alarm the operator. The enhancement processing of lofargrams using a relaxation method could be one part of the automatic system of lofargram processing to provide available target information for good decisions. The objective of this thesis is to enhance spectral lines of the lofargram by using the relaxation method which is an iterative approach to line detections.
Type
Thesis
Description
Series/Report No
Department
Engineering Acoustics
Organization
Identifiers
NPS Report Number
Sponsors
Funder
Format
vii, 65 p.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
Copyright is reserved by the copyright owner.