National Instruments IMAQTM 用户手册

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Refer to the source code of the CWMachineVision control for an example of how to 

use the CWIMAQVision methods. 

Use the objects to group related input parameters and output parameters to 
certain methods, thus reducing the number of parameters that you actually 
need to pass to those methods.

ActiveX objects in 

cwimaq.ocx

 have a CWIMAQ prefix, objects in 

niocr.ocx

 

have an NIOCR prefix, and objects in 

cwmv.ocx

 have a CWMV prefix.

You must create an ActiveX object before you can use it. You can use the 

New

 keyword in Visual Basic to create these objects. For example, use the 

following syntax to create and store an image in a variable named 

image

:

Dim image As New CWIMAQImage

If you intend to develop an application in Visual C++, National Instruments 

recommends that you use IMAQ Vision for LabWindows/CVI. However, if you decide 
to use IMAQ Vision for Visual Basic to develop applications for Visual C++, you can 
create objects using the respective Create methods on the CWIMAQVision control or 
CWMachineVision control. For example, to create a CWIMAQImage object, use the 

CWIMAQVision.CreateCWIMAQImage

 method.

Figures 1-1 and 1-2 illustrate the steps for creating an application with 
IMAQ Vision. Figure 1-1 describes the general steps for designing a 
Vision application. The last step in Figure 1-1 is expanded upon in 
Figure 1-2. You can use a combination of the items in the last step to create 
a IMAQ Vision application. For more information about items in either 
diagram, refer to the corresponding chapter listed beside the item.

Diagram items enclosed with dashed lines are optional steps.