User`s guide

Acquiring Image Data
5-3
acquire data. With hardware triggers, you start the object and it waits until it receives a
signal from an external device to start acquiring data.
The toolbox handles immediate and manual triggering automatically; you do not have to
include any special processing in your adaptor. Supporting hardware triggers, requires
some adaptor development work. For more information, see “Supporting Hardware
Triggers” on page 5-27.
Overview of Virtual Functions Used to Acquire Data
The pure virtual functions in your adaptor class that you must implement work together
to acquire data. However, the main steps are:
1
Specify the format of the video data in the getMaxHeight(), getMaxWidth(),
getNumberOfBands(), and getFrameType() functions — see “Specifying the
Format of the Image Data” on page 5-5.
2
Open a connection with your device in the openDevice() function — see “Opening
and Closing Connection with a Device” on page 5-10.
3
Start acquiring data in the startCapture() function — see “Starting and Stopping
Image Acquisition” on page 5-15.
4
Stop acquiring data in the stopCapture() function — see “Starting and Stopping
Image Acquisition” on page 5-15.
5
Close the connection with the device in the closeDevice() function — see
“Opening and Closing Connection with a Device” on page 5-10.
The following diagram shows this flow of control in graphical form. This diagram
picks up where the diagram in Chapter 3 ends, after the object has been created — see
“Acquiring Image Data” on page 5-2.
Note The diagrams do not show the calls your adaptor makes to the image acquisition
device's SDK because these calls vary with each device's SDK.