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Proceedings Paper

Postprocessing of point target detection sinusoidal filters
Author(s): Charlene E. Caefer; Jerry Silverman; Steven DiSalvo; Richard W. Taylor
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Paper Abstract

In previous conference, we described a powerful class of temporal filters with excellent signal to clutter gains in evolving cloud scenes of consecutive IR sequences. The generic temporal filter is a zero-mean damped sinusoid, implemented recursively. The full algorithm, a triple temporal filter (TTF), consists of a sequence of two zero-mean damped sinusoids followed by an exponential averaging filter. The outputs of the first two filters are weakened at strong local edges. Analysis of a real-world database led to two optimized filters: one dedicated to noise-dominated scenes, the other to cloud clutter-dominated scenes; a dual-channel fusion of the two filters has also been implemented in hardware. This paper describes the post-processing and thresholding of the outputs of the filter algorithms. Post-processing on each output frame is implemented by a simple spatial algorithm which searches for maximum linear or pseudo-linear streaks made up of three linked pixels. The output histogram after post-processing is more robust to histogram- based thresholding and in some cases has improved signal to clutter ratio. The threshold is based on a simple level-occupancy (binary) histogram in which the first gap of 4 empty levels is determined and a threshold established based on this gap value and the number of occupied levels in the histogram above the gap. The post-processing and thresholding of the filter outputs are now operating in real-time hardware. Preliminary flight tests on a small aircraft of the algorithms in real-time operation demonstrate the viability of the approach on a moving platform. Specific examples and a video of the real-time performance on a fixed and moving platform will be presented at the conference.

Paper Details

Date Published: 13 July 2000
PDF: 8 pages
Proc. SPIE 4048, Signal and Data Processing of Small Targets 2000, (13 July 2000); doi: 10.1117/12.391970
Show Author Affiliations
Charlene E. Caefer, Air Force Research Lab. (United States)
Jerry Silverman, Air Force Research Lab. (United States)
Steven DiSalvo, Air Force Research Lab. (United States)
Richard W. Taylor, Air Force Research Lab. (United States)

Published in SPIE Proceedings Vol. 4048:
Signal and Data Processing of Small Targets 2000
Oliver E. Drummond, Editor(s)

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