Справочник Пользователя для National Instruments IEEE 1394
Chapter 2
Basic Acquisition with NI-IMAQ for IEEE 1394 Cameras
© National Instruments Corporation
2-9
Snap
A snap acquires a single image into a user buffer. Figure 2-2 illustrates the
typical programming order of a high-level snap acquisition.
typical programming order of a high-level snap acquisition.
Figure 2-2. High-Level Snap Flowchart
Use a snap for low-speed or one-shot applications where ease of
programming is essential. When you invoke a snap, the driver opens a
session on a camera and initializes the IEEE 1394 camera. Opening a
session sets the ROI to the size of the video mode you selected in MAX.
programming is essential. When you invoke a snap, the driver opens a
session on a camera and initializes the IEEE 1394 camera. Opening a
session sets the ROI to the size of the video mode you selected in MAX.
Note
If you do not have a valid session, a temporary session is created using
cam0
.
Then, the snap acquires the next incoming image into a user buffer. After
the image is acquired, the program calls image processing and analysis
functions. When the processing and analysis functions are finished, the
program calls the Close function using the camera handle. This function
instructs NI-IMAQ to free all of the resources associated with this camera,
which releases the session.
the image is acquired, the program calls image processing and analysis
functions. When the processing and analysis functions are finished, the
program calls the Close function using the camera handle. This function
instructs NI-IMAQ to free all of the resources associated with this camera,
which releases the session.
Initialize
Opens and Configures Camera
Executes User-Specific Image
Processing
Processing
Closes the Camera Session
Acquires Image into Buffer
Snap
User-Specific Functions
Close