Re: Umax Astra 6x0S - CCD distance - Do they *really* do this that way
Rogier Wolff (R.E.Wolff@BitWizard.nl)
Fri, 20 Feb 1998 09:45:34 +0100 (MET)
> Hi !
> > After this change, all images (except the 4 resolutions above) need to
> > be ccd-corrected, but with a float ccd value, -1 < ccd < 1
> > The only way I find to ccd-correct those images is to add part of the
> > current line value for a given channel with part of the above line value
> > for the same channel and to use this value.
> > For example, with a float ccd of .12, I take 88% (100-12) of the current
> > line + 12% of the above line for blue channel and 76% (100-12*2) of the
> > current line + 24% (12*2) of the above line for the green channel. If
> > float ccd is <0, I swap the % values. [This is for Astra 610S, for 600S,
> > replace green with red].
> > >From my point of view, this may lead to reduce image quality, but I
> > can't find another way to do this.
> >From information-theory point of view this does not reduce image quality.
> There exists an inverse transformation, so no information lost.
> Actually I might consider doing this for the MFS12000 alternate correction
> scheme, which now only handles full-line distances.
The image quality does get reduced.
Samples: 0 0 34 56 23 37 67 83 0 0
no-loss averaging: 0 0 17 45 39 30 52 75 41 0 0
is blurred: I just averaged every pixel-pair together....
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