National Instruments IMAQTM - Manual (Page 54)

Chapter 5 Performing Machine Vision Tasks
IMAQ Vision for Visual Basic User Manual 5-2 ni.com
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
regions of interest rather than the entire image. To use this technique, the
parts of the object you are interested in must always appear inside the
regions of interest you define.
If the object under inspection is always at the same location and orientation
in the images you need to process, defining regions of interest is simple.
Refer to the
Set Search Areas section of this chapter for information about
selecting a region of interest.
Often, the object under inspection appears rotated or shifted in the image
you need to process with respect to the reference image in which you
located the object. When this occurs, the ROIs must shift and rotate with
the parts of the object in which you are interested. For the ROIs to move
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 it appears shifted and
rotated in the image you need to process. This coordinate system is referred
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