Slide 25 of 37
Notes:
The physics of objects determines the relationship between the signal that strikes the object and the echo that returns from it. The basic element of the echo is a copy of the outgoing signal simply reflected from the front face of the object. If the impedance between the object and the water matches sufficiently, then there will be other reflections from the internal structure of the object, which may include sound traveling via a number of different paths through and around the object. The material of the object can also have resonance characteristics which will be excited by the echolocation signal. In addition, there may be other objects in the vicinity (clutter) that also return complex echoes. All of these "features" add together and form the complex time series received by the dolphin. The dolphin filters through this mass of data to derive the characteristics of the object to which it is attending.
