Research Summaries

Back Calibrated SAS, Relevance to ATR

Fiscal Year 2018
Division Graduate School of Engineering & Applied Science
Department Oceanography
Investigator(s) Olson, Derek R.
Sponsor Office of Naval Research (Navy)
Summary Current high-frequency synthetic aperture sonar (SAS) imaging systems and processing software have been largely successful in producing high-quality imagery in a variety of oceanographic and seafloor environments. In most high-frequency real aperture and SAS systems, the image pixel values have been adjusted for optimal viewing by operators. The dynamic range of the pixel values may be truncated and the mean background level may vary from image to image, even across images of the same geographic area. Automated Target Recognition (ATR) algorithms that process these images require that pixel energy levels are normalized to remove systematic variations in amplitude that can cause these algorithms to fail. However, the adaptive nature of image normalization algorithms can introduce artifacts as well. In many cases the discarded original pixel values may contain valuable information. Calibrated SAS images, defined as images whose pixel values represent only the scattering properties of the seafloor or target, present a promising input to ATR because 1) they preserve amplitude information, which may provide stable feature measurements to ATR, and 2) they can be normalized without artifacts by taking into account propagation and scattering physics, potentially offering a superior method than current normalization techniques.
Keywords Calibration scattering strength synthetic aperture sonar
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