JFTR, A simple ray tracing showing the concept of Koehler illumination.[0] [0] https://www.researchgate.net/figure/A-simple-ray-tracing-showing-the-concept-of-

JFTR, A simple ray tracing showing the concept of Koehler illumination.[0] [0] https://www.researchgate.net/figure/A-simple-ray-tracing-showing-the-concept-of-Koehler-illumination-Three-point-sources-A_fig1_238033404 https://www.researchgate.net/figure/A-simple-ray-tracing-sho...