Supplying a total input events/point source/second is the preferred activation input. This is converted to input events/point source/CCD frame according to the frame time in ModeParams. The input PSFimage is normalised to unity, and from this the localised pixel-by-pixel count rate per frame is established.

The calculation depends on the pattern types selected, with progressively more
complex arithmetic for the larger patterns (see J Ballet *Ast Ap Suppl Ser*
v 135 pp371-381).

The output intensity () in each case is modelled as follows, where
is the input intensity per pixel :
**Mono-Pixels**

where

and the are the fractional pattern occurrences taken from the
pattern library CCF, but corresponds to patterns 1,2,3 and 4 ,
corresponds to patterns 5,6,7 and 8 and corresponds to patterns 9,10,11 and 12.

**Bi-Pixels**

where

**Tri-Pixels**

where

**Quad-Pixels**

where