J-M Deniel : Radioprotection 2024 , 59 ( 4 ), 327 – 337 329
Fig . 2 . Measurement conditions in front of the INRS metal furnace : in the front , the AvaSpec NIR256-2.5TEC spectroradiometer is protected by a survival blanket ; in the rear , its optics and the camera face the furnace opening . Note that a pipe reduces the spectroradiometer measurement field to approximately the furnace opening . Fig . 3 . . Z 0 distance offset from a reference point on the camera body to the camera optical center .
Considering each pixel p a rectangle , its ff p form factor corresponds to a rectangle-based solid angle v p as illustrated in Figure 5a .
Several methods can be used to exactly compute ff p ( Cohen and Greenberg 1985 ). We used the straightforward Carre method ( Carré , 1998 , pp . 67-68 ) ( see Fig . 5b ) based on the Nusselt analogy ( see Fig . 10.3 in DiLaura et al ., 2011b , p . 10.7 ).
In this method , polygonal surfaces in space are projected on a unitary disc of center O . A polygon is a series of [ AB ]