From: nze christian (christian_nze@hotmail.com)
Date: 12/02/02-01:20:16 PM Z
Hi,
The double scan result in a better , because the 2 scans will be different;
the noise will not happen on the same point. The sofware will do an average
which mean that when the scan give the same result for a point, the software
let them like they are but when it give different result it will make the
average of the to point. this method is used in microscopy ofr astronomy
where single pmt are used. They often average to 8 or 16 which mean that
they scan 8 16 to avoid noise. a point should always give the same result
on the 8 scan, if not it apply a function or delete the point considered as
pure noise.
In our case the noise just come from the receptor, as there is no change in
the light and in the photo. so this way to work avoid to many machine noise.
<If you double scan you still have the same signal to noise ratio,
<therefore
<no increase in dynamic range because you are just summing together to
<scans
<with the same signal to noise ratio. Unless you have software that can
<detect noise and remove it one is just fooling self. As far as I know
<this does not exist.
Amicalement
Nzé Christian
mailto:christian_nze@hotmail.com
http://www.c-nze.com
> >
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