Research Summaries

Back Investigation into calibrated synthetic aperture sonar for target detection

Fiscal Year 2020
Division Graduate School of Engineering & Applied Science
Department Oceanography
Investigator(s) Olson, Derek R.
Sponsor Office of Naval Research (Navy)
Summary This activity is focused on applied research related to Mine/Obstacle Detection. The project will investigate the utility of using calibrated sonar imagery for automatic target recognition (ATR). Currently, imagery with normalized pixel values are used in ATR. This study will identify changes in feature variability due to several calibration approaches: 1) a current HF SAS beamforming approach that produces imagery meant to be analyzed by a human operator, 2) a beamforming approach that sets a common mean background level referenced to an arbitrary scattering strength, and 3) a sophisticated calibrated beamforming approach that is capable of estimating strength. A calibrated HF SAS ATR algorithm will then be coded into the Modular Algorithm Testbed Suite (MATS) to compare performance at the system level. A second part of the study will look at the effect of variability on calibrated measurements. The focus of this research effort will be to study sources of systematic and random uncertainty in calibrated measurements, and to study the degree to which calibrated measurements can be compared across measurement systems, sensing modality (real vs. synthetic aperture), and frequency. This effort will consider scattering strength measured by different sensors and processing algorithms and uncertainty due to ocean variability. In the former, the effects of finite bandwidth, angular, and spatial resolution on estimated scattering cross section will be investigated The latter will be used to establish a link between the ocean environment and coherent gain of synthetic aperture sonar (SAS) arrays. A comprehensive understanding of the coherence loss from various sources (oceanographic, motion estimation, random rough surface scattering) will have enormous impact on other techniques using SAS.
Keywords
Publications Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal
Data Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal