I hate math, but lets see if I have this close.
F(xpincushion) = (k)* ((Y*Y)X)
F(ypincushion) =(k)*((x*x)Y)
F(Xtrapazoid) = (k)*(YX)
F(Ytrapazoid) = (k)*(XY)
F(Xrotation) =(K)*(Y)
F(Yrotation)=(k)*(x)
F(Xlinearity) = ((k*Y)+X)
F(Ylinearity) = ((k*x)+Y)
Where K = the potentiometer settings
Sum the transfer functions.
Hint, in a relative sort of way, BOW and PINCUSHION are the same to the chips, just polar opposites in a differential world........ 
F(m) = ((x1-x2) * (y1-y2))/10
That is all I'm sayin......
Don't even think to ask for my copy of the schematic of yet a third design (NOT LSDI, NOT LFI) I promised I would not disclose that hardware.
This patent's hardware is atrociously huge, but it does give you the functions in the right terms. US Patent 4,518,898 I actually had the board for that patent at one time out of a CRT typesetter. The board was 18 x 24 inches, and I got tired of the space it took, so I scrapped it when GC became common in software.
I worked for a surplus company in college, and much to my delight, right around when LSDI released theirs, I found the board in the typesetter. If I was not a member of ILDA at the time, I would have had no idea what that typesetter board was.
This is so trivial for a PC to do, for most graphics. It is very useful when your in a dome , however, there is a alternative, if you can find a reflective sphere to scan on first.
Steve
Last edited by mixedgas; 06-22-2009 at 05:15.
Qui habet Christos, habet Vitam!
I should have rented the space under my name for advertising.
When I still could have...