National Instruments IMAQ Vision for LabWindows TM /CVI - Manual (Page 54)

Chapter 5 Performing Machine Vision Tasks
IMAQ Vision for LabWindows/CVI User Manual 5-2 ni.com
Figure 5-1 illustrates the basic steps involved in performing machine vision
inspection tasks.
Figure 5-1. Steps to Performing Machine Vision
Note Diagram items enclosed with dashed lines are optional steps.
Locate Objects to Inspect
In a typical machine vision application, you extract measurements from
ROIs rather than the entire image. To use this technique, the parts of the
object you are interested in must always appear inside the ROI you define.
If the object under inspection is always at the same location and orientation
in the images you need to process, defining an ROI is simple. Refer to
the
Set Search Areas section of this chapter for information about selecting
an ROI.
Often, the object under inspection appears rotated or shifted relative to the
reference image in which you located the object. When this occurs, the
ROIs need to shift and rotate with the parts of the object in which you are
interested. To move the ROIs with the object, you must define a reference
coordinate system relative to the object in the reference image. During the
measurement process, the coordinate system moves with the object when
Display Results
Locate Objects to Inspect
Set Search Areas
Find Measurement Points
Convert Pixel Coordinates to
Real-World Coordinates
Make Measurements
Identify Parts Under Inspection
Classify
Objects
Read
Characters
Read
Symbologies