Filmscanners mailing list archive (filmscanners@halftone.co.uk)
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: filmscanners: Noise correction algorithms
Lynn Allen writes ...
> Ryan wrote:
>
> > How does a computer know that the blue in your
> > picture is from the sky? Or that the red in your
> > picture is a sunset and not a sportscar? :-)
>
> ...
>
> I believe it has to do with matrixes, which I don't pretend to
understand,
> on the programming level. If a surrounding field is "blue" and one
or
> several "red" pixels show up in it, are they supposed to be there?
Logic
> would say, "No." ...
You are describing the "median" filter, which will replace a pixel
if a surrounding pixel is more common. However, as you probably know,
you want a filter even smarter, because the median will soften more
than we would like ... but it still should be tried before "blurring"
(... unless blurring is the effect you want ...)
shAf :o)
|
