National Instruments IMAQ Vision for LabWindows TM /CVI - Manual (Page 33)

Chapter 3 Making Grayscale and Color Measurements
IMAQ Vision for LabWindows/CVI User Manual 3-4 ni.com
You can display the IMAQ Vision tools palette as part of an ROI
constructor window or in a separate, floating window. Follow these steps
to invoke an ROI constructor and define an ROI from within the ROI
constructor window:
1. Use imaqConstructROI2() to display an image and the tools palette
in an ROI constructor window, as shown in Figure 3-2.
Figure 3-2. ROI Constructor
2. Select an ROI tool from the tools palette.
3. Draw an ROI on your image. Resize and reposition the ROI until it
designates the area you want to inspect.
4. Click OK to output a descriptor of the region you selected. You can
input this ROI descriptor into many analysis and processing functions.
You can also convert the ROI descriptor into an image mask, which
you can use to process selected regions in the image. Use
imaqROIToMask() to convert the ROI descriptor into an image mask.
You can also use imaqSelectPoint() , imaqSelectLine() ,
imaqSelectRect() , and imaqSelectAnnulus() to define regions
of interest. Complete the following steps to use these functions.
1. Call the function to display an image in an ROI Constructor window.
Only the tools specific to that function are available for you to use.
2. Draw an ROI on your image. Resize or reposition the ROI until it
covers the area you want to process.