User`s guide

6 Acquiring Image Data
6-24
Controlling Logging Parameters
In this section...
“Data Logging” on page 6-24
“Specifying Logging Mode” on page 6-24
“Specifying the Number of Frames to Log” on page 6-25
“Determining How Much Data Has Been Logged” on page 6-26
“Determining How Many Frames Are Available” on page 6-28
“Delaying Data Logging After a Trigger” on page 6-31
“Specifying Multiple Triggers” on page 6-32
Data Logging
The following subsections describe how to control various aspects of data logging.
• Specifying the logging mode
• Specifying the number of frames to log
• Determining how many frames have been logged since the object was started
• Determining how many frames are currently available in the memory buffer
• Delaying data logging after a trigger executes
• Specifying multiple trigger executions
Specifying Logging Mode
Using the video input object LoggingMode property, you can control where the toolbox
logs acquired frames of data.
The default value for the LoggingMode property is 'memory'. In this mode, the toolbox
logs data to a buffer in memory. If you want to bring image data into the MATLAB
workspace, you must log frames to memory. The functions provided by the toolbox to
move data into the workspace all work with the memory buffer. For more information,
see “Bringing Image Data into the MATLAB Workspace” on page 7-3.
You can also log data to a disk file by setting the LoggingMode property to 'disk' or to
'disk&memory'. By logging frames to a disk file, you create a permanent record of the
frames you acquire. For example, this code sets the value of the LoggingMode property
of the video input object vid to 'disk&memory'.