User`s guide

5 Acqu iring Image Data
Logging Image Data to Disk
In this section.. .
“Logging Data to Disk” on page 5-40
“Creating an AV I File Object for Logging” on page 5-41
“Example: Logging Data to Disk” on page 5-43
Logging Data to Disk
While a video input object is running, you can log the image data being
acquired to a disk file. Logging image data to disk provides a record of your
data.
To set up data logging to disk, perform the se steps:
1 Create a disk file to store the data. The toolbox logs the data to disk in
Audio Video Interleave (AVI) format because this format provides data
compression capabilities that allow for e fficient storage. You must use the
MATLAB
avifile function to create this log file. For more information, see
“Creating an AVI File Object for Logging” on page 5-41.
2 Set the value of the video input object L oggingMode property to 'disk' or
'disk&memory'.
3 Set the valu
e of the video input object
DiskLogger property to the AVI
file objec
t created in step 1.
The follow
ing figure shows how the toolbox adds frames to the AVI file when
atriggero
ccurs. With each subsequent trigger, the toolbox a ppends the
acquired f
rames to the end of the AVI file. The frames must have the same
dimensio
ns. For an example of how to set up disk data lo gging, see “Exa mple:
Logging D
ata to Disk” on page 5-43.
5-40