User`s guide

Using VideoDevice System Object to Acquire Frames
14-5
Using VideoDevice System Object to Acquire Frames
You can use these functions with the VideoDevice System object.
Function Purpose
 
step Acquire a single frame from the image acquisition device.
frame = step(obj);
acquires a single frame from the VideoDevice System object, obj.
Note that the first time you call step, it acquires exclusive use of
the hardware and will start streaming data.
release Release VideoDevice resources and allow property value
changes.
release(obj)
releases system resources (such as memory, file handles, or
hardware connections) of System object, obj, and allows all its
properties and input characteristics to be changed.
isLocked Returns a value that indicates if the VideoDevice resource is
locked. (Use release to unlock.)
L = isLocked(obj)
returns a logical value, L, which indicates whether properties are
locked for the System object, obj. The object performs an internal
initialization the first time the step function is executed. This
initialization locks properties and input specifications. Once this
occurs, the isLocked function returns a value of true.
preview Activate a live image preview window.
preview(obj)
creates a Video Preview window that displays live video data for
the VideoDevice System object, obj. The Video Preview window
displays the video data at 100% magnification (one screen pixel
represents one image pixel). The size of the preview image is