National Instruments IMAQTM 用户手册

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You can use the color matching capability of IMAQ Vision to compare or 
evaluate the color content of an image or regions in an image.

Complete the following steps to compare colors using color matching:

1.

Select an image containing the color information that you want to use 
as a reference. The color information can consist of a single color or 
multiple dissimilar colors, such as red and blue.

2.

Use the entire image or regions in the image to learn the color 
information using 

CWIMAQVision.LearnColor

, which stores the 

results of the operation in a CWIMAQColorInformation object that 
you supply as a parameter. The color information object has a color 
spectrum that contains a compact description of the color information 
that you learned. Refer to Chapter 14, Color Inspection, of the 
IMAQ Vision Concepts Manual for more information. Use the 
CWIMAQColorInformation object to represent the learned color 
information for all subsequent matching operations.

3.

Define an entire image, a region, or multiple regions in an image as the 
inspection or comparison area.

4.

Use 

CWIMAQVision.MatchColor

 to compare the learned color 

information to the color information in the inspection regions. This 
method returns an array of scores that indicates how close the matches 
are to the learned color information.

5.

Use the color matching score as a measure of similarity between the 
reference color information and the color information in the image 
regions being compared.

When learning color information, choose the color information carefully:

•

Specify an image or regions in an image that contain the color or color 
set that you want to learn.

•

Specify the granularity required to represent the color information. 

•

Choose colors that you want to ignore during matching.