Abstract:

Underwater imaging is very essential in providing underwater observations and inspections. Due to the limitation of optical systems, underwater imaging is useful to deal with many applications for example involving underwater explorations. The purpose of this paper is to describe and develop a simple technique that able to give an understanding in the formation and reconstruction of 3-D short-range acoustic images, mainly for underwater applications. The prototype of the underwater imaging test-bed is developed using small size tank that equipped with a lower beam sonar transducer. The surface of the water tank is divided into x-y coordinates depending on how accurate data is desired. By sending sonar signal, raw reflected signal can be acquired by the acoustic system. A single sonar transmitter is manually arranged so that it mimics the beamforming typically forms by an array of transmitter. Data collected at every single coordinate with respect to x-y axis is analyzed and simulated using Matlab software to construct 2-D and 3-D images. Since the underwater imaging experiments rely on speed of sound, the resolution of the 2-D and 3-D images are different depends on the properties of water. Therefore the limitation of sensing images due to the effect of various condition of water; i.e salinity, temperature and pressure can also be studied by repeating the same technique. The final goal of this paper is to establish the state of art of the techniques for short-range acoustic image formation and reconstruction using small scale test-bed tank.

Keywords:

underwater imaging, acoustic images, beamforming.