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© National Instruments Corporation vii IMAQ Vision for LabWindows/CVI User Manual
Defining a Search Area.....................................................................5-16
Setting Matching Parameters and Tolerances...................................5-17
Testing the Search Algorithm on Test Images..................................5-18
Using a Ranking Method to Verify Results......................................5-19
Finding Points Using Color Pattern Matching ................................................5-19
Defining and Creating Good Color Template Images ......................5-20
Training the Color Pattern Matching Algorithm...............................5-21
Defining a Search Area.....................................................................5-22
Setting Matching Parameters and Tolerances...................................5-23
Testing the Search Algorithm on Test Images..................................5-25
Finding Points Using Color Location..............................................................5-25
Convert Pixel Coordinates to Real-World Coordinates.................................................5-26
Make Measurements......................................................................................................5-26
Distance Measurements...................................................................................5-26
Analytic Geometry Measurements..................................................................5-27
Instrument Reader Measurements...................................................................5-27
Identify Parts Under Inspection.....................................................................................5-28
Classifying Samples ........................................................................................5-28
Reading Characters..........................................................................................5-29
Reading Barcodes............................................................................................5-30
Reading 1D Barcodes........................................................................5-30
Reading Data Matrix Barcodes.........................................................5-30
Reading PDF417 Barcodes...............................................................5-31
Display Results ..............................................................................................................5-31
Chapter 6
Calibrating Images
Perspective and Nonlinear Distortion Calibration.........................................................6-1
Defining a Calibration Template.....................................................................6-2
Defining a Reference Coordinate System .......................................................6-3
Learning Calibration Information....................................................................6-5
Specifying Scaling Factors................................................................6-6
Choosing a Region of Interest...........................................................6-6
Choosing a Learning Algorithm .......................................................6-6
Using the Learning Score..................................................................6-7
Learning the Error Map.....................................................................6-8
Learning the Correction Table..........................................................6-8
Setting the Scaling Method...............................................................6-8
Calibration Invalidation ....................................................................6-8
Simple Calibration.........................................................................................................6-9
Save Calibration Information.........................................................................................6-10
Attach Calibration Information......................................................................................6-10