This project examined the capability of an ultrasonic three dimensional (3-D) visualization system to provide the undisturbed characterization and identification of submerged shallow-buried objects. Analysis of a location by this system would provide a visual image of individual buried unexploded ordnance (UXO) not visible on the surface.
The 3-D Ultrasonic system was originally developed at University of California, Los Angeles’ (UCLA) School of Civil and Environmental Engineering by Dr. Scott Brandenberg. The goal was to study the potential of using p-wave reflection imaging for geotechnical engineering. The demonstration system was adapted for underwater use by SPAWAR Systems Center, Pacific. The ultrasonic system components are off-the-shelf hardware consisting of two ultrasonic transducers, source pulser, receiver amplifier, receiver analog filter, terminal block, data acquisition cards mounded in a PXI chassis, a laptop computer running the control and data processing software, and the underwater delivery vehicle with the X-Y positioning system. The vehicle is the benthic flux sampling device (BFSD) with the X-Y positioning system attached. It is composed of a X-Y gantry system operated by underwater servo motors controlled by the operator’s computer. For this project, the flux sampling equipment was removed and replaced by the X-Y positioning system.
The results for each performance objective are provided below:
After wide area assessment of underwater UXO, there is often insufficient information to classify UXO from clutter or non-UXO items. Before remediation planning can begin, these debris fields must be classified as hazardous (UXO-containing) or nonhazardous (debris only). This is traditionally done by digging up shallow buried potential munitions/UXO at spot locations by Navy-trained and certified underwater explosive ordnance disposal (EOD) teams. Traditional removal, identification, and disposal of these buried objects by trained EOD teams is slow, expensive, and, for benign objects, unnecessary. Undisturbed identification of these buried objects either by a single diver using a handheld sensor, by a remotely operated vehicle (ROV)-mounted sensor, or in shallow water, by a pole-mounted sensor would greatly speed up spot identification, paving the way for more cost-effective remediation and cleanup planning.