Experimental setup for underwater artifact identification and signal analysis using wavelets

A New Compressing Ultrasonic Data Algorithm Based on Wavelets

“…The transducer device has a central frequency of 2.25 MHz and is carried by a three-axis translational mobile system moving over water surface in the tank. The position of the transducer along the x, y, and z axes is controlled by three stepper motors [5] . The experiment consists of placing an object target at the bottom floor of the tank and scanning its surface by means of ultrasonic signals generated by energizing the transducer using a discrete-frequency true sinusoidal tone-burst signal of finite duration.…”

“…The ultrasonic transducer translates the electrical signal into mechanical vibrations transmitted within the elastic medium and then reflected and refracted at the impact of the object target or the bottom floor. The orientation of the flux of reflected and refracted waves are defined by the well known Descartes laws of optics where the optic index is replaced by the speed C of the acoustic waves [5,6] . The reflected waves will be detected by the transducer translating them into electrical signals named echoes, which will later be amplified and filtered.…”

“…Underwater objects identification is of a great importance to a large number of environmental problems and civilian applications [1][2][3][4][5][6] , such as seabed mapping, archaeological object recognition, and wreckage detection. The availability and the expensive cost of ultrasonic tests in real mediums such as sea and lakes has led to the use of laboratory tanks for measurements, with gated signals and time-windowing to isolate reflections.…”

“…In the recent years a considerable interest has arisen regarding the use of Wavelet as a new transform technique for signal processing applications. This technique has shown effective results in several applications such as nonlinear noise filtering, image and signal compression, edge detection and feature extraction [5][6][7][8][9][10][11][12][13] .…”

Prospective of the application of ultrasounds in archaeology

“…Imaging applications consists of obtaining tomographic representations of underground and underwater archaeological sites and objects. Some examples of this application are the following: imaging of the stern section of a shipwreck obtained by an ultrasound triangulation system composed of three receivers and two emitters [2]; an experimental setup for underwater artefact identification [3]; a cave internal structure based on a 3D model from ultrasound reflections, which was used for several simulations including the sediment flow inside the cave [4]; underground interface estimation to be used in exploration of comparatively large archaeological sites [5]; and a precise localizer and sketcher of archaeological findings after they are extracted by archaeologists [6]. The use of ultrasounds for cleaning in archaeology have covered applications such as ultrasound brushing of archaeological metal-made objects [7], isolating a suspension of binder carbonates from bulk mortars in mortar radiocarbon dating [8], and removal of contaminants in archaeological bone analysis [9].…”