Optimisation in Signal and Image Processing

Chapter 8

Bayesian Inference and Markov Models

8.1.  Introduction and application framework

Marine sciences rely on the use of different methods and different tools to be able to carry out research on what the seabed is made up of: this includes the use of geotechnical tools (isolated well-logging, on site samples) as well as side-scan sonar devices and multi-beam sounding systems which transform the characteristics of the seabed interface into images.

Investigation systems which are used and which are based on a high resolution sonar. imaging system are tools that pr ovide a solution to the problems linked to the detection of small objects that can be found on the seabed. After the emission of a sonar wave, the detection of these small objects can be carried out in one of two ways: first of all, it is possible to detect the behavior of a signal which is reflected by the object, and secondly there is a certain level of interference that is generated by the presence of this object (in the case of objects which are slightly buried in the sediment of the sea bed). It is therefore necessary that the dimensions and the location of such objects be compatible with the sonar’s ability to detect them. In the case of an anechoic object, it is the formation of the acoustic shadow which makes it possible to detect and then classify the object. In this chapter we will not deal with the issues that arise during the design of a sonar system, nor will we deal with the issues which led to the ...