SAA8112HL Datasheet, PDF (12/40 Pages) NXP Semiconductors – Digital camera signal processor and microcontroller

Philips Semiconductors
Digital camera signal processor and
microcontroller
Product specification
SAA8112HL
8.4 Colour matrix
A programmable 3 × 3 colour matrix (see Fig.4) is used to
convert the extracted colour information, either Y, (2R-G),
(2B-G) or R, G and B from the sensor colour space into a
standard RGB colour space.
With B and W sensors, a unity matrix is used.
8.4.1 RGB PROCESSING
At the colour matrix output, the video signal is in RGB
format. The following processing is applied on the RGB
signals in this order:
• The gain of the red and blue streams can be changed to
control the white balance
• A black offset (positive or negative) correction can be
applied independently on each of the R, G and B signals
• A Knee function with adjustable gain and threshold can
be applied to the signal to compress the highlights
• Finally, a Gamma function is applied; the Gamma curve
is adjustable.
The same Knee and Gamma functions are applied on the
three R, G and B signals.
handbook, full pagewidth
R or (2R−G)
G or Y
B or (2B−G)
COLOUR
MATRIX
Rgain
×
Bgain
×
Rblack
+
Gblack
+
Bblack
+
KNEE
R
GAMMA
G
B
FCE341
Fig.4 RGB processing diagram.
2000 Jan 18
12