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Re: filmscanners: Polaroid Optical Density
Hemingway, David wrote:
>Simply, multi-scanning attempts to identify the pixels
> that change from scan to scan, These pixels are most likely noise and when
> statistically identified as such can be removed and replaced with values for
> adjacent pixels
I found it interesting to read the process used by Polaroid in determining
optical density (even though David hasn't given his competitors details of the
statistical analysis used or the acceptable level of noise).
However, I was surprised at David's description of multi-scanning to reduce
noise by identifying pixels that change from scan to scan. I had thought that
multi-scanning just averaged the values for each scan of each pixel rather than
using adjacent pixel values.
Bob Armstrong
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