National Instruments IEEE 1394 Manual De Usuario

© National Instruments Corporation

Many acquisition VIs require an image buffer to receive the captured 
image. You can create this image buffer with IMAQ Create. Refer to the 

 section of this chapter for more information about 

using buffers. Image In receives the image buffer. Image Out 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 whose elements are defined as Left, 
Top, Right, and Bottom. If Region of Interest is not wired, the entire 
image acquisition window is captured. Configure the default acquisition 
window using MAX.

Two types of acquisition VIs are available in LabVIEW: high-level and 
low-level.

Use the high-level acquisition VIs for basic image acquisition applications. 
VIs are included for snap, grab, and sequence, as described in the 

 section of this chapter. 

Use the low-level acquisition VIs for more advanced image acquisition 
applications. The low-level VIs configure an acquisition, start an 
acquisition, retrieve the acquired images, and stop an acquisition. You can 
use these VIs to construct advanced IMAQ applications.

Complete the following general steps to perform a low-level acquisition.

1.

Call IMAQ1394 Init to initialize the board and create an IMAQ1394 
Session.

2.

Call IMAQ1394 Configure Acquisition to allocate resources for the 
acquisition.

3.

Call IMAQ1394 Start Acquisition to start transferring data from the 
camera.