User`s guide

Basic Image Acquisition Procedure
Step 5: Configure Object Properties (Optional)
After creating the video input object and previewing the video stream, you
might want to modify characteristics of the image or other aspects of the
acquisition process. You accomplish this b y se tti n g the v alues of image
acquisition object properties. This section
• Describesthetypesofimageacquisition objects used by the toolbox
• Describes how to view all the properties supporte d by these objects, with
their current values
• Describes how to se t the value s of obje ct properties
Types of Image Acquisition Objects
The to olbox uses two types of objects to represent the connection with an
image acquisition device:
• Video input objects
• Video source objects
A video input object represents the connection between MATLAB and a video
acquisition device at a high level. The propertie s supported by the v ideo inp u t
object are the s ame for every type of dev ice. You cre ated a video input object
using the
videoinput function in step 3.
When you create a video input object, the toolbox automatically creates one or
more video source objects associated wi t h the v ideo input object. Each video
source object represents a collection of one or more physical data sources that
aretreatedasasingleentity.Thenumber of video source objects t he toolbox
creates depends on the device and the video format you specify. At any one
time, only one of the v ideo source objects, called the selected source, can be
active. T his is the source used for acquis ition. For more information about
these im age acqu isition objects, see “Crea tin g Image Acquisition Objects”
on page 4-9.
V iewing Object Properties
To view a complete list of all the properties supported by a video input object
or a video source object, use the
get function. To list the properties of the
video input object created in step 3, enter this code at the MATLAB prompt.
1-13