A Comparative study on Applying Acoustic Ground Discrimination Systems in Persian Gulf for Marine Researches

Persian Gulf is the most strategic waterways in the world due to its importance in the global oil transportation and its underwater inspection. It becomes an essential part of both today's economy and military. The utilization of underwater exploration can also be attributed to the various disciplines of underwater research: archaeology, biology, geophysics, cultural resource management, and so on. In almost any underwater operation that takes place on or under the seafloor, it is necessary to have an understanding of the makeup of the seabed below the site and sediment. Moreover, to manage the marine environment effectively maps which reveal the geophysical characteristics of the seabed are essential, since they allow the wide-scale geology and Holocene sedimentary processes to be determined and understood. In addition, offshore sediment dynamics play an important role in the long term stability and geomorphology of the coastline which is an important consideration when planning flood and coastal sea defense schemes. Today, sonar systems become a common technology for underwater exploration including seabed classification. They are available in a number of different configurations such as side-scan, forward look, swath, sub-bottom, and multi-beam and provide near-photographic images of underwater areas, even in zero visibility water. In recent years, many automatic acoustic ground discrimination systems such as RoxAnn and QTC-View and Echo Plus automatic seabed classification were developed; but because of different classification methods, they produce different results for the same region. Some of these systems are susceptible to noise and ship speed. In a large extent, taking good result from a system depends on the skill and experience of the user and the intended use of the system. In addition, usually sea bottoms having similar acoustic signatures for a particular classification system are not necessarily similar. Therefore, most of acoustic seabed classification systems are essentially empirical devices, which may work well for some bottoms but not others. In addition, they require intensive calibration (ground trotting) when used to discriminate seabed types. In this paper, the problem of seafloor segmentation and classification of Persian Gulf using automatic acoustic ground discrimination systems will be addressed. Different techniques and instruments in this area will be introduced. The advantages and drawbacks of each one will be discussed. Then, the feasibility study of doing such a work in Persian Gulf region will be expressed and finally, based on a the Roxann instrument of the research ship belongs to National Cartographic Organization, some practical results will be outlined.