Studies of multi-Look SAS techniques for target detection and classification
Abstract
"Optimally suited for SAS systems which operate with large relative bandwidths and transmit beamwidths, multi-look coherence explores the information content of images by splitting the total angle and frequency spectral bandwidth of a complex synthetic aperture sonar image into subbands. The complex coherence of each pixel as a function of frequency and angle can then be exploited, yielding information on the type of scattering observed (i.e., specular, diffuse, pointlike, resonance-related, etc.). Information pertaining to scattering type would improve the separability of man-made targets from the interfering background signal, as targets should have features that scatter coherently in frequency and/or angle versus the random seafloor interface or volume (or randomly rough, target-sized rock) which will scatter incoherently. The primary objective of the proposed work is to perform follow-on studies of multi-look coherence techniques for broadband complex SAS imagery. These studies will provide additional information on the multi-look technique as a method for separating scattering mechanisms with the ultimate goal being the discovery of features in coherence which may better separate targets and random backgrounds. This type of analysis may also reduce the simulation space required for effective on- or off-board ATR and ATR simulation. Although the initial studies on the multilook technique has demonstrated possibilities for improved target detection via clutter reduction as well as possibilities for target classification, structured studies on the proposed coherence technique are still lacking in terms of: 1) a detailed experimental analysis on gains for buried targets; 2) further analysis of modeled data to tease out specifics on dominant coherent target features; and 3) a comparison of target detection performance against traditional intensity-based methods. We have experience both with the physics of the broadband scattering involved and with the SAS processing required for a study of multi-look coherence. Via modeling and analysis of SAS data collected on both man-made and natural targets, as well as from the seafloor (interface and volume), we will delineate situations when the technique succeeds or fails (and more importantly why the technique may succeed or fail). It is hoped that systematic follow-on studies of the multilook coherence technique will yield results that will prove useful for broadband SAS systems currently in operation or envisioned to operate in the future."
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 29, 2020
- Source ID
- N000142012255
Entities
People
- Anthony P. Lyons
Organizations
- Office of Naval Research
- United States Navy
- University System of New Hampshire