Remote sensing in underwater archaeology: simulation
of side scan sonar images using ray tracing techniques 

V.S. Blake 

Ray tracing is a well known technique in computer graphics. Rays of light are followed backwards from the eye through all their reflections and refractions until an image is built up. In this research project, sound is also thought of as being made of "rays" and these rays are followed in the same way, thus building up a simulated sonar image.

The following images show how a sunken ship might look if all the water were removed, together with the simulated side scan sonar image of the same scene. (Sonar fish towed along parallel to the length of the ship, simulating one beam or one side only)

However, ships are rarely going to sit upright on the bottom - they will be broken up by tides and currents, and nibbled by wee beasties. The next images show the scene after the ship has sunk a little into the sand and the masts have been toppled.

For the details of the method, please see Publications