Seminar - David Blair - Use of One-Bit Digitisation in Underwater Acoustic Imaging

Wednesday 2 August 2006, 1.10 - 1.50 pm
Civil Engineering Lecture Theatre 3

Abstract
Underwater acoustic imaging (UAI) is useful for many applications, including imaging damaged oil rigs and shipwrecks. UAI is particularly useful in muddy or turbid waters, where optical imaging fails. UAI requires an array of pressure sensors. In order to keep costs manageable, the sensor signals (as a function of discrete time) can be digitised to one bit (that is, only the sign of the pressure or voltage is detected). However, one-bit digitisation leads to problems and puzzles. The speaker and his collaborators have investigated these by a program that simulates a simplified imaging device. Among the results obtained is a quantitative account of how, in a one-bit system, a strong target can mask the presence of a weaker target some distance away.