National Instruments IMAQ Vision for LabWindows TM /CVI - Manual (Page 6)

Contents
© 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