Consider a pinhole projection circle (PPC with diameter d) scanning along the diagonal line (CC) to the circular landmark (diameter d) as shown in Fig. 1, where s is the distance from the intersecting line to the PPC center C. In other words, s = +d/2 and s= -d/2 when the PPC just touches the outside and inside of the landmark, respectively. a) Derive the mathematical expression for da/80 as a function of S(=s/d), where da is the overlapping area and 80 is the pin-hole projection area, in terms of the ratio p(=dld). b) Plot da/ 80 for the range, -0.5