As for the averaging of the captures, it would be even better to do a median filter on 3 captures.
so given a row of pixels from three different captures:
(n1),(x2),(x3)
(x1),(n2),(x3)
(x1),(x2),(n3)
where x is a good pixel, and n is a noisy pixel, averaging would give you:
2/3*x1 + 1/3*n1 , 2/3*x2 + 1/3*n2 , 2/3*x3 + 1/3*n3
whereas a median filter would give:
(x1),(x2),(x3)
Even better to use 3 captures from 3 different laserdiscs to remove laser rot, but that I suspect is out of reach. I would love to help with the Avisynth scripting if you would like.
Do you plan on de-interlacing also?
-G