Biomimetic Sonar for Object Recognition

Abstract

Man-made sonar has had limited success for object recognition because the echo waveform varies significantly with the location of the object within the acoustic beam pattern. The variation of the echo from the same object located in different parts of the beam is typically significant [1], This variation was minimized in previous experiments by careful placement of the objects in a stationary sonar field and by using objects that are large compared to the wavelength and that have shapes (spheres, cubes, pyramids and cones) that exhibit very different scattering properties [2, 3]. The system described in this paper exploits the important biological principle of mobility by translating and rotating the sonar in order to standardize the view of the object by positioning it at a constant location. The sonar design is motivated by bats, whose ears react by rotating to the direction of the echo source, and by dolphins, who appear to move as if to position the object at a standard location in the beam pattern [4, 5, 6].