National Instruments IMAQTM 用户手册

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3-1
3
Making Grayscale and Color 
Measurements
This chapter describes how to take measurements from grayscale and color 
images. You can make inspection decisions based on image statistics, such 
as the mean intensity level in a region. Based on the image statistics, you 
can perform many machine vision inspection tasks on grayscale or color 
images, such as detecting the presence or absence of components, detecting 
flaws in parts, and comparing a color component with a reference. 
Figure 3-1 illustrates the basic steps involved in making grayscale and 
color measurements.
Figure 3-1.  Steps to Taking Grayscale and Color Measurements
Define Regions of Interest
An ROI is an area of an image in which you want to focus the image 
analysis. You can define an ROI interactively, programmatically, or with 
an image mask. 
Defining Regions Interactively
You can interactively define an ROI in a viewer that displays an image. Use 
the tools from the right-click menu to interactively define and manipulate 
the ROIs. Table 3-1 describes each of the tools and the manner in which 
you use them.
Define Regions of Interest
Measure
Grayscale Statistics
Measure
Color Statistics