Matrox CronosPlus, Установка и справочник по оборудованию

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24 Chapter 4: Hardware reference
of available channels for the type of input (DCF type), as opposed to all available
channels. Then, specify the appropriate digitizer when performing the grab
(
MdigGrab() ).
Low-pass filter
The input low-pass filtering stage is used to limit high frequency noise and aliasing
effects at the input of the decoder. The filters used on Matrox CronosPlus are
4th order Butterworth filters with a cut-off frequency of 8 MHz.
Video decoder
A multi-standard video decoder is used to convert NTSC and PAL analog video
signals that are composite (CVBS) or component (Y/C) to digitized component
video. The decoder supports BGR 8:8:8:8 (32-bit), BGR 8:8:8 (24-bit), and YUV
4:2:2 output pixel formats. Note that YUV 4:2:2 output pixel formats are grabbed
as YUYV.
The video decoder also features automatic gain control (AGC). However, you can
disable this feature (MIL-Lite
MdigControl() with
M_GRAB_AUTOMATIC_INPUT_GAIN
set to
M_DISABLE
).
The video decoder also features an adaptive multi-line comb filter for better Y/C
separation, as well as an on-chip scaler, which can reduce the video image size in
both horizontal and vertical directions independently. The full resolution can be
scaled down to any value between 1 and 1/64. The video decoder can also crop
the image to the required width and height, as well as flip the image vertically
and/or horizontally.
Trigger
Matrox CronosPlus accepts an external trigger input which allows image
acquisition to be synchronized to external events. The trigger is synchronous to
the incoming video stream, and is received through an opto-coupler that isolates
the rest of the circuitry from outside surges.
Matrox CronosPlus operates in next valid frame/field mode. When in this mode,
the digitizer waits for the next valid frame or field (as specified by the DCF file)
before commencing the grab. This trigger mode functions in one of two ways:
• Edge-triggered monoshot acquisition: The PCI bus master interface waits for the
rising/falling edge to capture a single frame.