Calculation of occlusions - Determine perspective component occlusion
"Normal", entocentric lenses have a fixed aperture angle. In the absolute center of the image, the viewing angle is zero degrees, so the component is viewed perpendicular in the center. Towards the edge, the angle of view increases more and more.
However, if there are elevated interfering contours outside the center, this leads to perspective shadowing or occlusion towards the edge. The width of the occlusion behind such disturbing contours can be calculated here: