Time-frequency filtering for classifying targets in nonstationary clutter

Vikram Thiruneermalai Gomatam; Patrick Loughlin

doi:10.1117/12.2050526

13 June 2014 Time-frequency filtering for classifying targets in nonstationary clutter

Vikram Thiruneermalai Gomatam, Patrick Loughlin

Proceedings Volume 9090, Automatic Target Recognition XXIV; 90900E (2014) https://doi.org/10.1117/12.2050526
Event: SPIE Defense + Security, 2014, Baltimore, MD, United States

Abstract

Classifying underwater targets from their sonar backscatter is often complicated by induced or self-noise (i.e. clutter, reverberation) arising from the scattering of the sonar pulse from non-target objects. Because clutter is inherently nonstationary, and because the propagation environment can induce nonstationarities as well, in addition to any nonstationarities / time-varying spectral components of the target echo itself, a joint phase space approach to target classification has been explored. In this paper, we apply a previously developed minimum mean square time-frequency spectral estimation method to design a bank of time-frequency filters from training data to distinguish targets from clutter. The method is implemented in the ambiguity domain in order to reduce computational requirements. In this domain, the optimal filter (more commonly called a “kernel” in the time-frequency literature) multiples the ambiguity function of the received signal, and then the mean squared distance to each target class is computed. Simulations demonstrate that the class-specific optimal kernel better separates each target from the clutter and other targets, compared to a simple mean-squared distance measure with no kernel processing.

Citation Download Citation

Vikram Thiruneermalai Gomatam and Patrick Loughlin "Time-frequency filtering for classifying targets in nonstationary clutter", Proc. SPIE 9090, Automatic Target Recognition XXIV, 90900E (13 June 2014); https://doi.org/10.1117/12.2050526

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