User`s guide

Retrieving Event Information

8-11

Start the image acquisition object — Start the image acquisition object. By

default, the object executes an immediate trigger, acquires 10 frames of data, and

then stops.

start(vid)

View the event log — Access the EventLog property of the video input object. The

execution of the video input object generated three events: start, trigger, and stop.

Thus the value of the EventLog property is a 1x3 array of event structures.

events = vid.EventLog

events =

1x3 struct array with fields:

Type

Data

To list the events that are recorded in the EventLog property, examine the contents

of the Type field.

{events.Type}

ans =

'Start' 'Trigger' 'Stop'

To get information about a particular event, access the Data field in that event

structure. The example retrieves information about the trigger event.

trigdata = events(2).Data

trigdata =

AbsTime: [2004 12 29 16 40 52.5990]

FrameMemoryLimit: 139427840

FrameMemoryUsed: 0

FrameNumber: 0

RelativeFrame: 0

TriggerIndex: 1

Clean up — Always remove image acquisition objects from memory, and the

variables that reference them, when you no longer need them.

delete(vid)

clear vid