National Instruments NI-IMAQ 用户手册
Chapter 3
Programming with NI-IMAQ for 1394
© National Instruments Corporation
3-7
Calling
imaq1394SetupGrab
initializes a session for a grab acquisition.
After
imaq1394SetupGrab
, each successive grab copies the last acquired
buffer into a user buffer where you can perform processing on the image.
Use grab for high-speed applications where you need processing performed
on only one image at a time. Figure 3-3 illustrates a typical grab
programming order.
Use grab for high-speed applications where you need processing performed
on only one image at a time. Figure 3-3 illustrates a typical grab
programming order.
Figure 3-3. Grab Programming Flowchart
The
Grab1394.c
example demonstrates how to perform a grab using
imaq1394Grab
. The example performs multiple grabs until an appropriate
condition is met. The program configures the session to perform a grab
operation by calling the
operation by calling the
imaq1394Grab
function.
The program then calculates the area to grab using the current ROI and
bytes per pixel. In this example, the program allocates a user buffer for
grabbing and passes this buffer to
bytes per pixel. In this example, the program allocates a user buffer for
grabbing and passes this buffer to
imaq1394Grab
. When the acquisition is
complete, it stops. The program then frees the user buffer and all of the
resources associated with this camera by calling
resources associated with this camera by calling
imaq1394Close
.
imaq1394CameraOpen
imaq1394CameraOpen
opens
and configures the camera
according to the file set up by
Measurement & Automation Explorer.
according to the file set up by
Measurement & Automation Explorer.
imaq1394Grab
and imaq1394GrabImage
copy the contents of the driver buffer
to a user buffer. You can call
to a user buffer. You can call
imaq1394Grab
and imaq1394GrabImage multiple times
for high-speed acquisition.
for high-speed acquisition.
User-specific image processing
imaq1394Close
closes the camera and session.
imaq1394SetupGrab
configures the camera for a
continuous acquisition.
imaq1394SetupGrab
imaq1394Grab
or imaq1394GrabImage
User-Specific Functions
imaq1394Close
(Loop)