Phytec FireWire-CAM-011H, Manual

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The Camera in Detail
© PHYTEC Messtechnik GmbH 2006 L-680e_1
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Figure 44: Spectral Filter Characteristics (FireWire-CAM-012H / -112H)
Please note that with a G-pixel it is impossible to say anything about
the red or blue portion of the light. Wavelengths between 400 and
500 nm can only be measured with B-pixels. Wavelengths between
600 and 700 nm can only be measured with R-pixels.
The problem is therefore that a pixel can only measure one of the three
colors, while we require all three color values at each pixel position
for an RGB image.
The Bayer pattern model uses the „spatial color interpolation“ to
generate an RGB image from the neighboring color pixels.
Let’s assume that we have an R-pixel and we require the missing G-
and B-values. The interpolation algorythm estimates these values
based on the neighboring pixels of the R-pixel. If it finds a
neighboring B-pixel with a high gray value and a G-pixel with a low
gray value, then it is quite probable that the R-pixel is probably
colored lilac.
For each pixel we have one measured and two estimated color values.
As with all modern cameras this interpolation is carried out in the
color cameras of the FireWire-CAM series by a signal processor.