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Chapter 5
Performing Machine Vision Tasks
Instrument Reader Measurements
Identify Parts Under Inspection
Classifying Samples
IMAQ Vision for Visual Basic User Manual
•
—Finds the line that is midway between a point and a
FindMidLine
line and is parallel to the line.
•
FindPolygonArea
vertex points.
You can make measurements based on the values obtained by meter, LCD,
and barcode readers.
Use
CWIMAQMeterArc.CreateFromPoints
CWIMAQMeterArc.CreateFromLines
gauge that you want to read.
calibrates the meter using the initial position and the full-scale position
of the needle.
CWIMAQMeterArc.CreateFromPoints
meter using three points on the meter: the base of the needle, the tip of
the needle at its initial position, and the tip of the needle at its full-scale
position. Use
CWIMAQVision.ReadMeter
needle using the CWIMAQMeterArc object.
Use
CWIMAQVision.FindLCDSegments
interest around each digit in an LCD or LED. To find the area of each
digit, all the segments of the indicator must be activated. Use
CWIMAQVision.ReadLCD
In addition to making measurements after you set regions of inspection,
you also can identify parts using classification, OCR, and barcode reading.
Use classification to identify an unknown object by comparing a set of its
significant features to a set of features that conceptually represent classes
of known objects. Typical applications involving classification include the
following:
•
Sorting—Sorts objects of varied shapes. For example, sorting different
mechanical parts on a conveyor belt into different bins.
•
Inspection—Inspects objects by assigning each object an identification
score and then rejecting objects that do not closely match members of
the training set.
—Calculates the area of a polygon specified by its
to calibrate a meter or
CWIMAQMeterArc.CreateFromLines
to calculate the regions of
to read the digits of an LCD or LED.
5-28
or
calibrates the
to read the position of the
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