On Sun, Apr 30, 2000 at 08:45:19AM -0700, Jan Steinman wrote:
>
> By moving cells (or moving your source material) an increment of the
> cell size, you in effect average half of two adjacent cells, but the
> result is no different than if you did it in software, except slower.
> Manufacturers should (IMHO) call this "mechanical interpolation,"
> rather than mis-labeling it as optical resolution.
>
The improvement of image quality due to shifting the array is caused by getting
more color information:
A digital color image requires three independent brightness values for each
pixel ( red/green/blue).
A CCD-Chip-cell can only give one color information ( red , green or blue)
from a pixel. To determine the color information 4 Pixels (1 red 1 blue and 2
green) beside each other work together, and the missing values are calculated
with an interpolation algorithm.
This means only 1/3 of the image data is realy acquired data, 2/3 is
interpolated.
Whereas a scanner determine the whole color-information for ervery pixel, which
is better.
With shifting the array, diffrent color-Elements swap their position, to get
the missing data.
A one step shift lead`s to get 2/3 of the pixel information, and with a double
shift (bidirectional)
you can get all the necessary information without interpolation.
So you don`t get a higher resolution due to a pixel shift, but you get better
image data.
> I don't understand how a hexagonal array would provide higher
> resolution, unless they are mechanically shifting the array somehow,
> which would then simply yield mechanical interpolation.
>
> I suspect the hexagonal array allows them to better use a given area
> of silicon, thus improving yield and lowering cost,. Then some bright
> marketing guy and some engineer got together and figured out a
> sophisticated way to exploit the hex array so they could lie about
> resolution.
>
As far as I know, it is an marketing trick. A hexagonal array gives better
(sharper)
results than a rectangular array with the same resolution. So Fuji decided to
specify the double amount of pixels to give the Consumer an idea of the quality
.
In Germany they got a dissuasiveness for this specification because of stricter
competittion laws.
Frieder Faig
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