User`s guide

5 Connecting to Hardware
5-8
Creating Image Acquisition Objects
In this section...
“Types of Objects” on page 5-8
“Video Input Objects” on page 5-8
“Video Source Objects” on page 5-8
“Creating a Video Input Object” on page 5-9
“Specifying the Video Format” on page 5-11
“Specifying the Selected Video Source Object” on page 5-13
“Getting Information About a Video Input Object” on page 5-14
Types of Objects
After you get information about your image acquisition hardware, described in “Getting
Hardware Information” on page 5-2, you can establish a connection to the device by
creating an image acquisition object. The toolbox uses two types of image acquisition
objects:
• Video input object
• Video source object
Video Input Objects
A video input object represents the connection between MATLAB and a video acquisition
device at a high level. You must create the video input object using the videoinput
function. See “Creating a Video Input Object” on page 5-9 for more information.
Video Source Objects
When you create a video input object, the toolbox automatically creates one or more video
source objects associated with the video input object. Each video source object represents
a collection of one or more physical data sources that are treated as a single entity. The
number of video source objects the toolbox creates depends on the device and the video
format you specify.
At any one time, only one of the video source objects, called the selected source, can be
active. This is the source used for acquisition. The toolbox selects one of the video source