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NI Vision 2009 for LabVIEW Help

Edition Date: June 2009

Part Number: 370281L-01

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Select ROIs in your images to limit the areas in which you perform your processing and inspection. You can define ROIs interactively or programmatically.

Defining Regions Interactively

The following table shows which ROI to use with a given measurement VI.

ROI	Measurement VI
Rotated rectangle	IMAQ Find Pattern 2 IMAQ Clamp Horizontal Max IMAQ Clamp Horizontal Min IMAQ Clamp Vertical Max IMAQ Clamp Vertical Min IMAQ Find Edge IMAQ Find Straight Edges
Annulus	IMAQ Find Circular Edge IMAQ Find Concentric Edge

Defining Regions Programmatically

When you design an automated application, you need to define ROIs programmatically. You can programmatically define regions in two ways:

Specify the elements of the ROI descriptor.
Specify regions by providing basic parameters that describe the region you want to define. You can specify a rotated rectangle by providing the coordinates of the top-left point, bottom-right point, and the rotation angle. You can specify an annulus by providing the coordinates of the center, inner radius, outer radius, start angle, and end angle. You can specify a point by setting its x-coordinates and y-coordinates. You can specify a line by setting the coordinates of the start and end points.