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Chapter 4 Programming with NI-IMAQ for 1394 VIs
© National Instruments Corporation 4-3 NI-IMAQ for IEEE-1394 Cameras User Manual
The most commonly used VIs are on the IMAQ for IEEE-1394 palette.
You can find VIs for basic acquisition and changing attributes.
The Motion and Vision»IMAQ for IEEE-1394»IMAQ Low Level
palette contains VIs for more advanced applications.
See the NI-IMAQ for IEEE-1394 VI Reference help for more information.
Common NI-IMAQ for 1394 VI Parameters
IMAQ1394 Session is a unique identifier that specifies the Interface file
used for the acquisition. It is produced by the IMAQ1394 Init VI and used
as an input to all other NI-IMAQ VIs. The NI-IMAQ for 1394 VIs use
IMAQ1394 Session Out, which is identical to IMAQ Session, to simplify
dataflow programming. IMAQ1394 SessionOut is similar tothe duplicate
file sessions provided by the file I/O VIs. The high-level acquisition
VIs—IMAQ1394 Snap, IMAQ1394 Grab Setup, and IMAQ1394
Sequence—require you to wire IMAQ1394 Session In only if you are
using an interface other than the default
cam0
, if you are using multiple
cameras, or if you need to set IMAQ 1394 properties before the acquisition.
Many acquisitionVIs require that you supply animage buffer toreceive the
captured image. You can create this image buffer with theIMAQCreate VI.
Consult the Buffer Management section of this chapter for more
information. The input that receives the image buffer is Image in.The
Image out output returns the captured image.
The acquisition VIs use the Region of Interest input to specify a
rectangular portion of an image frame to be captured. You can use Region
of Interest to reduce the size of the image you want to capture. Region of
Interest is an array of four elements with theelements defined asLeft, Top,
Right, Bottom. If Region of Interest is not wired, the entire image
acquisition window is captured. You configure the default acquisition
window using MAX.
Note
TheRegionofInterestinputisonlyusedwhenyourcameraisconfiguredtouse
Scalable Image Format (format 7).