How I Learned to Stop Worrying and Love Uncalibrated Sonar

Dr. Anthony P. Lyons
Research Professor


Friday, Mar. 25, 2016, 3:00pm
Chase 130

The estimation of relative or absolute seafloor height fields from side-looking imaging sonar systems has been an active area of research for several decades. Topographic measurements (or the heights and shapes of objects on the seafloor) made with uncalibrated side-looking sonar systems generally use interferometry between signals obtained with two closely-space hydrophone arrays. Other possibilities for estimating topography exist, including clinometry which uses intensity information in single images (e.g., shape-from-shading or shape-from-shadow techniques) and stereogrammetry, a technique based on optical photogrammetry which utilizes the parallax of pairs of images of the same area acquired with two different viewing angles. Changes in image statistics caused by random seafloor roughness may also be used for estimating seafloor roughness parameters, such as ripple heights or root-mean-square slopes. This talk reviews the different methods which can be used to extract topography or roughness parameters with uncalibrated sonar systems and discusses the respective advantages, difficulties and constraints for each technique. We further assess the possibility of using combinations of these techniques as complementary sources of data.


Dr. Anthony P. Lyons conducts research in the field of underwater acoustics and acoustical oceanography. His current areas of interest include high-frequency acoustic propagation and scattering in the ocean environment, acoustic characterization of the seafloor, and quantitative studies using synthetic aperture sonar.

Anthony received the B.S. degree (summa cum laude) in physics from the Henderson State University, Arkadelphia, AR, in 1988 and the M.S. and Ph.D. degrees in Oceanography from Texas A&M University, College Station, TX, in 1991 and 1995, respectively. He was a Scientist at the SACLANT Undersea Research Centre, La Spezia, Italy, from 1995 to 2000, and the Applied Research Laboratory at Penn State from 2000 to 2014. He also served as an Associate Director with the Office of Naval Research Global in 2008 and 2014. In 2003, Dr. Lyons was awarded the Institute of Acoustics' A.B. Wood Medal. He is a Fellow of the Acoustical Society of America and a member of the IEEE Oceanic Engineering Society. He is also currently an Associate Editor for the Journal of the Acoustical Society of America and is on the Editorial Board for the international journal Methods in Oceanography.