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National Instruments IMAQ Vision for Measurement Studio Source and Destination Images

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Chapter2 GettingMeasurement-Ready Images

IMAQVision for LabWindows/CVI User Manual 2-4 ni.com

Source and Destination Images

Some IMAQ Vision functions that modify the contents of an image have

sourceimage and destination image input parameters. The source image

receivest he image to process. The destination image receivesthe

processingresults. The destination image can receive either another image

orthe original, depending on y our goals. If you do not want the contents of

the original image to change, use separate source and destination images.

Ifyou want to replace the original image with the processed image, pass the

same image as both the source and destination.

Dependingon the functi on, the image type of the destination image can be

thesame or different than the image type of the source image. The function

descriptions in the IMAQVision for LabWindows/CVI function reference

helpinclude the type of images you can use as image inputs and outputs.

IMAQVision resizes the destination image to hold the result if the

destination is not the appropriate size.

The followingexamples illustrate source and destin ation images with

imaqTranspose():

•imaqTranspose(myImage,myImage);

Thisfunction creates a transposed image using the same image for the

sourceand d estination. The contents of myImage change.

•imaqTranspose(myTransposedImage,myImage);

Thisfunction creates a transposedimage and stores itin a d estination

differentfrom the source. The myImage image remains unchanged,

and myTransposedImagecontains the result.

Functions that perform arithmetic or logical operations between two

imageshave two source images and a destination image. You can perform

an operation betweentwo images and then either store the result in a

separatedestination image or in one of the two source images. In the

latter case, makesure you no l onger need the original data in the source

image before storing the result over the data.

The followingexamples show the possible combin ations using

imaqAdd():

•imaqAdd(myResultImage,myImageA, myImageB);

Thisfunction adds two source images (myImageA and myImageB)and

stores the result in a third image (myResultImage). Both source

imagesremain intactafter p rocessing.

Contents

Main IMAQ Page Important Information Warranty Copyright Trademarks WARNINGREGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS Conventions Contents Chapter 1 Introduction to IMAQ Vision Chapter 2 Getting Measurement-Ready Images Chapter 3 Grayscale and Color Measurements Chapter 4 Blob Analysis Chapter 5 Machine Vision Page Introduction to IMAQ Vision About IMAQ Vision Documentation and Examples Application Development Environments IMAQ Vision Function Tree Page IMAQ Machine Vision Function Tree Creating IMAQ Vision Applications Chapter1 Introductionto IMAQ Vision Figure1-2. InspectionSteps for Building a Vision Application IMAQVision for LabWindows/CVI User Manual 1-6 ni.com Getting Measurement-Ready Images Set Up Your Imaging System Calibrate Your Imaging System Create an Image Page Source and Destination Images AcquireorReadanImage Acquiring an Image Reading a File Converting an Array to an Image Display an Image Attach Calibration Information Analyze an Image Improve an Image Lookup Tables Filters Convolution Filter Nth Order Filter Grayscale Morphology FFT Page Complex Image Operations Grayscale and Color Measurements Define Regions of Interest Interactively Defining Regions Page Page Page Page Programmatically Defining Regions Defining Regions with Masks Measure Grayscale Statistics Measure Color Statistics Figure3-4. Primary Components of a Color Image Comparing Colors Learning Color Information Choosing the Right Color Information Specifying the Color Information to Learn Using the Entire Image Using a Region in the Image Using Multiple Regions in the Image Choosing a Color Representation Sensitivity Ignoring Learned Colors Blob Analysis Correct Image Distortion Create a Binary Image Improve the Binary Image Removing Unwanted Blobs Separating TouchingBlobs Improving Blob Shapes Make Particle Measurements Page Page Convert Pixel Coordinates to Real-World Coordinates Machine Vision Locate Objects to Inspect UsingEdgeDetectiontoBuildaCoordinateTransform Page Using Pattern Matching to Build a Coordinate Transform Page Chapter5 MachineVision NationalInstruments Corporation 5-7 IMAQVision for LabWindows/CVI User Manual ChoosingaMethodtoBuildtheCoordinateTransform Figure5-4. Buildinga Coordinate Transform Set Search Areas Interactively Defining Regions Programmatically Defining Regions Find Measurement Points Finding Features Using Edge Detection Finding Lines or Circles Figure5-5. Findinga Straight Feature Finding Edge Points Along One Search Contour Finding Edge Points Along Multiple Search Contours Finding Points Using Pattern Matching Defining and Create Good TemplateImages Symmetry Feature detail Positional information Background information Trainingthe Pattern Matching Algorithm Defining a Search Area Setting Matching Parameters and Tolerances Match Mode Minimum Contrast Rotation Angle Ranges Testingthe Search Algorithm on Test Images Using a Ranking Method to Verify Results Finding Points Using Color Pattern Matching Defining and Creating Good Color TemplateImages Color Information Symmetry Feature Detail Positional Information Trainingthe Color Pattern Matching Algorithm Defining a Search Area Setting Matching Parameters and Tolerances Color Sensitivity Search Strategy Color Score Weight Minimum Contrast Rotation Angle Ranges Testingthe Search Algorithm on Test Images Finding Points Using Color Location Convert Pixel Coordinates to Real-World Coordinates Make Measurements Distance Measurements Analytic Geometry Measurements Instrument Reader Measurements Display Results Page Calibration Perspective and Nonlinear Distortion Calibration Defining a Calibration Template Defining a Reference Coordinate System Page Page Learning Calibration Information Specifying Scaling Factors Choosing a Region of Interest Choosing a Learning Algorithm Using the Learning Score Learning the Error Map Learning the Correction Table Setting the Scaling Method Calibration Invalidation Simple Calibration Save Calibration Information Attach Calibration Information A Technical Support Resources Web Support NI Developer Zone Customer Education System Integration Worldwide Support Glossary Numbers/Symbols A B C Page D E F G H I Page J K L M N O P Page Q R S T Page Index A B C D E F G H I Page Page L M N O P R S T V W Z