Figure 5.

This figure demonstrates the geometry for calculating the two-layer delay profile. The solid line shows the position of the transducer whose element positions are described by r_e, where j indexes the transducer element. There is an interface position for each element position, which is described by r_i. The lateral component of r_i is what is actually found by finding the roots of equation (7). The wave’s point of origin is described by r_t.