Allied Guppy, Техническое руководство, Страница: 75 / 238

Description of the data path
GUPPY Technical Manual V4.0.1
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Finally, the calculated correction values can be read from the
WHITE_BALANCE register 80Ch.
Automatic white balance
There is also an auto white balance feature available which continuously
optimizes the color characteristics of the image.
As a reference, it uses a grid of at least 65535 (2
16
) samples equally spread
over the area of interest or a fraction of it. The position and size of the con-
trol area (Auto_Function_AOI) can be set via an advanced register (see Chap-
ter
Autofunction AOI on page 201).
AUTOFNC_AOI affects the auto shutter, auto gain and auto white balance fea-
tures and is independent of the Format7 AOI settings. If this feature is
switched off, the work area position and size represent the current active
image size.
The camera automatically adjusts the settings to the permitted values.
Due to the fact that the active image size might not be divisible by 4 without
a remainder, the autofunction AOI work-area size might be greater.
This allows for the positioning of the work area to be at the bottom of the
active image.
Another case is for outdoor applications: the sky will be excluded from the
generation of the reference levels when the autofunction AOI is placed at the
bottom of the image.
Figure 35: Automatic white balance sequence