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Chapter 3 Hardware Overview
IMAQ PCI/PXI-1411 User Manual 3-2 www.ni.com
Video Decoder
The PCI/PXI-1411 supports NTSC and PAL video standards in either
composite or S-Video format. The onboard video decoder converts the
incoming video signal to Red, Green, and Blue (RGB) data and passes
this data to the color-space processor for further processing.
The video decoder also allows you to control numerous parameters to
optimize an acquisition. You can independently adjust parameters such
as analog input range, brightness, contrast, saturation, or frequency range
(controlled by different filters). See the Measurement & Automation
Explorer online help for a complete description of the PCI/PXI-1411
video parameters.
Furthermore, the video decoder strips out all necessary clock and
synchronization signals included in the video signal and controls the
acquisition conditions automatically. High-quality circuitry regenerates
even bad timing signals allowing acquisitions from, for example, a video
cassette recorder (VCR).
Color-Space Processor and LUTs
The color-space processor receives the RGB data from the video decoder
and performs several different (optional) operations on the data before
passing them to the memory controller. Processing functions include the
following:
• Adjusting independent gain of the three signals (R, G, and B). You can
use independent gain to perform, for example, white balancing on the
acquired image.
• Applying three independent look-up tables (LUTs) to the R, G, and
B data.
• Converting the RGB data into Hue, Saturation, and Luminance (HSL).
• Processing the hue plane to clear pixels where the saturation
falls below a predefined threshold value. This function is called
post-decoding coring. You can use this function to remove part
of the image without color information (monochrome) that
otherwise would introduce noise on the hue plane.
The color-space processor can export the video data in 32-bit RGB or HSL
formats or in individual 8-bit hue, saturation, or luminance planes. For
more information on these image types, see the Image Representations
section in Appendix B, Introduction to Color.