Digital BW, The Print

> Todd,
> My understanding of the interpolation is that it takes the specific color
> information from the one sensor, and then it 'borrows' some data from the
> surrounding sensors to finish out the information it needs to make the pixel.

That sounds familiar.
 
> And although it's a sophisticated algorithm, it's still made up information,
> not
> reality.  And that is why there is not as much detail in a digital camera
> captures as a scanned film file of the same resolution.

That I never disputed. My only point was that each sensor did record detail,
which it does, but I was forgetting that each sensor has a filter over it.
Thus, although I'm *technically* correct that they each record detail, that
detail isn't useable as is (because of the filters) and needs to be factored
with the other sensors as you state above.

Never mind. ;-)

Todd


> 
>> I see. So without interpolation my little 4 pixel grid would be analogous to
>> putting on a camera lens a filter which is split into 4 quadrants of color,
>> which would give wacky data.
>> 
>> Then how is grayscale handled? Are every 4 sensors averaged into one, or is
>> interpolation done for each sensor individually?
>> 
>> Todd
>> 
>>> But in a typical digital camera there's a color filter placed over the chip
>>> such that your 4 pixel grid would be:
>>> 
>>> [R][G]
>>> [G][B]
>>> 
>>> ...so there's no way to take a pure grayscale image, because there's a color
>> 
>>> filter stuck on the chip. The camera can't not interpolate in greyscale
>>> mode, because the only data it's capable of capturing is alread filtered for
>> 
>>> color. See: http://www.foveon.com/interp.html
>>> 
>>> -Jason
>>> 
>>>> -----Original Message-----
>>>> From: Todd Flashner [mailto:tflash@...]
>>>> Sent: Thursday, February 07, 2002 1:23 AM
>>>> To: DigitalBlackandWhiteThePrint@yahoogroups.com
>>>> Subject: Re: [Digital BW] Re: Digicam in BW mode, how to test
>>>> 
>>>> Say your sensor is a grid of two sensors across by two down. In grayscale
>>>> mode you get a 4 pixel capture. You have 4 pixels of detail,
>>>> represented by
>>>> one channel which has 4 pixels.
>>>> 
>>>> If the camera then applies an algorithm to give each of those
>>>> pixels an RGB
>>>> component, that requires interpolation, and you'll end up 3 channels at 4
>>>> pixels each. You've added color channels, through interpolation, which may
>>>> or may not contain an accurate representation of the color they
>>>> are tying to
>>>> create, but you've added no detail.
>> 
> 
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