Figure 2

Illustration of the coordinate transformation, where the area surrounded by red circle in virtual space (a) is transformed into physical space (b). r0 is radius of screen, R0 is radius of PL. A, B and C represent different regions.

Illustration of the coordinate transformation, where the area surrounded by red circle in virtual space (a) is transformed into physical space (b). r0 is radius of screen, R0 is radius of PL. A, B and C represent different regions.