Chapter 3
Hardware Overview
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National Instruments Corporation
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Delayed acquisition—You can use either software or triggers to start
acquisitions instantaneously or after skipping a specific period of time.
You can use delayed acquisition for posttrigger applications.
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Frame/field selection—With an
camera and the PCI-1424 in
frame mode, you can program the PCI-1424 to start an acquisition on
any odd or even field.
Acquisition Window Control
You can configure numerous parameters on the PCI-1424 to control the
video acquisition window. A brief description of each parameter follows:
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Acquisition window—The PCI-1424 allows the user to specify a
particular region of active pixels and active lines within the incoming
video data. The
selects the starting pixel and
number of pixels to be acquired relative to the assertion edge of the
horizontal (or line) enable signal from the camera. The
selects the starting line and number of lines to be acquired
relative to the assertion edge of the vertical (or frame) enable signal.
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Region of interest
—
The PCI-1424 uses a second level of active pixel
and active line regions for selecting a region of interest. When you
disable the region-of-interest circuitry, the device stores the entire
acquisition window in onboard or system memory. However, when
you enable the region-of-interest circuitry, the device acquires only
a selected subset of the image frame.
•
Interlaced video—The PCI-1424 supports both interlaced and
non-interlaced, or progressive scan, digital video signals. In
interlaced mode, the PCI-1424 combines the odd and even fields
into one contiguous frame for analysis. In non-interlaced mode,
each field is treated as an independent frame.
