Manuale d’uso / di manutenzione del prodotto IMAQ Vision for LabWindows TM /CVI del fabbricante National Instruments
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IMAQ TM IMAQ Vision for LabWindows TM /CVI TM User Manual IMAQ Vision f or LabW indows/CVI User Manual August 2004 Edi tion Part Number 3712 66A-01.
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© National Instruments Cor poration v IMAQ Vision for LabWindows/CVI User Manual Contents About This Manual Conventions ............ .............. ........... .............. ............ .............. .............. ........... ............. i x Related Documentation .
Contents IMAQ Vision for LabWindow s/CVI User Manual vi ni.com Chapter 3 Making Grayscale and Color Measurements Define Regions of Interest .............. .............. ........... .............. .............. .............. ............ 3-1 Defining Regions Interactively .
Contents © National Instruments Cor poration vii IMAQ Vision for LabWindows/CVI User Manu al Defining a Search Area .............. .............. ........... .............. .............. .. 5-16 Setting Matching Parameters and Tolerances ..... .....
Contents IMAQ Vision for LabWindows/ CVI User Manual viii ni.com Appendix A Technical Support and Professional Services Glossary Index.
© National Instruments Corporation ix IMAQ Vision for LabWindows/CVI U ser Manual About This Manual The IMAQ Vision for LabWin dows/CVI User Manual is inten ded for engineers and scientists who have .
About This Manual IMAQ Vision for LabWindow s/CVI User Manual x ni.com Related Documentation In addition to this manual, the fol lo wing documentatio n resources are av ailable to help you create your vision application.
About This Manual © National Instruments Corporation xi IMAQ Vision for LabWindows/CVI U ser Manual Other Documentation • Y our National Instru ments image acquisition (I MA Q) de vice user manual—If you need installation instructions and device-specif ic information, refer to your device user manual.
© National Instruments Corporation 1-1 IMAQ Vision for LabWindows/CVI User Manual 1 Introduction to IMAQ Vision This chapter describes the IMAQ Vision for LabWin dows/CVI software, outlines the IMAQ Vision fu nction organization, and lists the steps for making a machine vision application.
Chapter 1 Introductio n to IMAQ Vision IMAQ Vision for LabWindows/ CVI User Manual 1-2 ni.com IMAQ Vision Function T ree The IMAQ Vision funct ion tree ( NIVision.lfp ) contains separate classes corresponding to groups or type s of functions. Table 1 -1 lists the IMAQ Vision function types and gives a description of each type.
Chapter 1 Introductio n to IMAQ Vision © National Instruments Corporation 1-3 IMAQ Vision for LabWindows/CVI User Manual IMAQ Machine Vision Function T ree The IMAQ Machine Vision function tree ( NIMachineVision.fp ) contains separate classes corresponding to g roups or types of functions.
Chapter 1 Introductio n to IMAQ Vision IMAQ Vision for LabWindows/ CVI User Manual 1-4 ni.com Creating IMAQ Vision Applications Figures 1-1 and 1-2 illustrate the step s for creating an application with IMAQ Vision. Figure 1-1 describ es the general steps to designing a Vision application.
Chapter 1 Introductio n to IMAQ Vision © National Instruments Corporation 1-5 IMAQ Vision for LabWindows/CVI User Manual Figure 1-1. General Steps for Designi ng a Vision Application Note Diagram items enclosed with da shed lines are optional steps.
Chapter 1 Introductio n to IMAQ Vision IMAQ Vision for LabWindows/ CVI User Manual 1-6 ni.com Figure 1-2. Inspection Steps for Building a Vision Application Note Diagram items enclosed with da shed lines are optional steps.
© National Instruments Corporation 2-1 IMAQ Vision for LabWindows/CVI User Manual 2 Getting Measurement-Ready Images This chapter describes how to set up your imagin g system, acquire and display an image, analyze the image, and prepare the image for additional processing.
Chapter 2 Getting M easure ment-Ready Images IMAQ Vision for LabWindows/ CVI User Manual 2-2 ni.com 3. Select an IMA Q device that meet s your needs. National Instruments of fers se veral IMA Q devices, includi ng analog color and monochrome devices as well as digital de vices.
Chapter 2 Getting Measurement-Ready Images © National Instruments Corporation 2-3 IMAQ Vision for LabWindows/CVI User Manual Y ou can create multiple images b y ex ecuting imaqCreateImage() as many times as you want. Determine the number of required images through an analysis of your intended application.
Chapter 2 Getting M easure ment-Ready Images IMAQ Vision for LabWindows/ CVI User Manual 2-4 ni.com Source and Destination Images Some IMAQ Vision func tions that modify the contents of an image have source image and destination image in put parameters.
Chapter 2 Getting Measurement-Ready Images © National Instruments Corporation 2-5 IMAQ Vision for LabWindows/CVI User Manual • imaqAdd(myImageA, myImageA, myIma geB); This function adds two source images and stores t he result in the first source image.
Chapter 2 Getting M easure ment-Ready Images IMAQ Vision for LabWindows/ CVI User Manual 2-6 ni.com Acquiring an Image Use one of the following methods to acquire images with a Nation al Instruments IMAQ devi ce. • Acquire a single image using imaqEasyAcquire() .
Chapter 2 Getting Measurement-Ready Images © National Instruments Corporation 2-7 IMAQ Vision for LabWindows/CVI User Manual Use imaqReadVisionFile() to open an image file containing additional information, such as calibration info rmation, template inform ation for pattern matching, or overlay information.
Chapter 2 Getting M easure ment-Ready Images IMAQ Vision for LabWindows/ CVI User Manual 2-8 ni.com Attach Calibration Information If you want to attach the calibratio n information of the curr ent setup to each image you acquire, use imaqCopyCalibr ationInfo() .
Chapter 2 Getting Measurement-Ready Images © National Instruments Corporation 2-9 IMAQ Vision for LabWindows/CVI User Manual If the image quality meets your needs, use the histogram to determine the range of pixel v alues that correspond to objects in the image.
Chapter 2 Getting M easure ment-Ready Images IMAQ Vision for LabWindows/CVI U ser Manual 2-10 ni.com Lookup T ables Apply lookup table (LUT) transformati ons to highlight image details in areas containing significan t information at the expense of other areas.
Chapter 2 Getting Measurement-Ready Images © National Instruments Cor poration 2-11 IMAQ Vision for LabWi ndows/CVI User Manual Convolution Filter The imaqConvolve() function allows you to use a predefined set of lowpass and highpass filters. Each filter is defined by a kernel of coefficients.
Chapter 2 Getting M easure ment-Ready Images IMAQ Vision for LabWindows/CVI U ser Manual 2-12 ni.com • Closing—Removes d ark pixels isolated in bright regions and smoot hs boundaries. • Proper -openi ng—Removes brig ht pixels isol ated in dark regio ns and smooths the inner contours of particles.
Chapter 2 Getting Measurement-Ready Images © National Instruments Cor poration 2-13 IMAQ Vision for LabWi ndows/CVI User Manual attenuation increases.
© National Instruments Corporation 3-1 IMAQ Vision for LabWindows/CVI User Manual 3 Making Grayscale and Color Measurements This chapter describes how to take m easurements from grayscale and color images. You can make inspection decisi ons based on image statistics, such as the mean intensity level in a region.
Chapter 3 Making Grayscale and Color Measurements IMAQ Vision for LabWindows/ CVI User Manual 3-2 ni.com T a ble 3-1 describes each of the tool s and the manner in which you use them. Table 3-1. T ools Palette Functions Icon T ool Name Function Selection T ool Select an R OI in the image and adjust the position of its control points and contours.
Chapter 3 Making Graysca le and Color Measurements © National Instruments Corporation 3-3 IMAQ Vision for LabWindows/CVI User Manual Hold down the <Shift> ke y while drawing an R OI to const rain the R OI to the horizontal, vertical, or diagonal axes.
Chapter 3 Making Grayscale and Color Measurements IMAQ Vision for LabWindows/ CVI User Manual 3-4 ni.com Y ou can display the IMA Q V ision tools palette as part of an R OI constructor window or in a separate, floating w indow . Follow these steps to in v oke an R OI constructor and define an R OI from within the R OI constructor window: 1.
Chapter 3 Making Graysca le and Color Measurements © National Instruments Corporation 3-5 IMAQ Vision for LabWindows/CVI User Manual 3. Click OK to populate a struct ure representing the R OI. Y ou can use this structure as an input to a variety of functions, such as the following functions that measure grayscale intensity .
Chapter 3 Making Grayscale and Color Measurements IMAQ Vision for LabWindows/ CVI User Manual 3-6 ni.com The following list describes ho w you can display the tools palette in a separate window and manipulate the palette. •U s e imaqShowToolWindow() to display the tools palette in a floating window .
Chapter 3 Making Graysca le and Color Measurements © National Instruments Corporation 3-7 IMAQ Vision for LabWindows/CVI User Manual or a labeled version of the binary im age as a mask image to the intensity measurement functi on. If you want to make color comp arisons, con vert the binary image i nto an R OI descriptor usin g imaqMaskToROI() .
Chapter 3 Making Grayscale and Color Measurements IMAQ Vision for LabWindows/ CVI User Manual 3-8 ni.com Figure 3-4. Primar y Components of a 32-Bit Color Image Figure 3-5.
Chapter 3 Making Graysca le and Color Measurements © National Instruments Corporation 3-9 IMAQ Vision for LabWindows/CVI User Manual Comparing Colors You can use the color matching capabilit y of IMAQ Vision to compare or evaluate the color content of an image or regions in an image.
Chapter 3 Making Grayscale and Color Measurements IMAQ Vision for LabWindows/CVI U ser Manual 3-10 ni.com Figure 3-6. T emplate Color Information The following sections explain when to learn the color information associated with an entire image, a reg ion in an image, or multiple regions in an image.
Chapter 3 Making Graysca le and Color Measurements © National Instruments Cor poration 3-11 IMAQ Vision for LabWi ndows/CVI User Manual Figure 3-8. Using a Single Region to Learn Color Distribution Using Multiple Regions in the Image The interaction of light w ith the objec t surface creates the observed color of that object.
Chapter 3 Making Grayscale and Color Measurements IMAQ Vision for LabWindows/CVI U ser Manual 3-12 ni.com Figure 3-9. Using Multiple Regions to Learn Color Distribution Choosing a Color Repr esentation Sensitivity When you learn a color, you need to sp ecify the sensi tivity required to specify the color information.
Chapter 3 Making Graysca le and Color Measurements © National Instruments Cor poration 3-13 IMAQ Vision for LabWi ndows/CVI User Manual Ignoring Learned Colors Ignore certain color components in color matching by rep lacing the corresponding componen t in the input color spectrum array to –1.
© National Instruments Corporation 4-1 IMAQ Vision for LabWindows/CVI User Manual 4 Performing Particle Analysis This chapter describes how to perfor m particle analysis on you r images. Use particle analysis to find statistical informat ion about particles—such as the area, location, and pres ence of particles.
Chapter 4 Per forming Particle Analysis IMAQ Vision for LabWindows/ CVI User Manual 4-2 ni.com If all the objects in your grayscale image are either brighter or dark er than your background, you can use imaqAutoThreshold() to automati cally determine the optimal threshold range and threshol d your image.
Chapter 4 Per forming Particle Analysis © National Instruments Corporation 4-3 IMAQ Vision for LabWindows/CVI User Manual Removing Unwanted Particles Use imaqRejectBorder() to remove particles that touch the border of the image. Reject particles on the bo rder of the image when you suspect that the information about tho se particles is incomplete.
Chapter 4 Per forming Particle Analysis IMAQ Vision for LabWindows/ CVI User Manual 4-4 ni.com isthmuses while close widen s the isth muses. Close and proper-close fill small holes in the particle.
Chapter 4 Per forming Particle Analysis © National Instruments Corporation 4-5 IMAQ Vision for LabWindows/CVI User Manual IMAQ_MT_BOUNDING_RECT_LEFT X-coordinate of the leftmost particle point IMAQ_M.
Chapter 4 Per forming Particle Analysis IMAQ Vision for LabWindows/ CVI User Manual 4-6 ni.com IMAQ_MT_EQUIVALENT_ELLIPSE_MAJOR_AXIS Length of the major axis of the ellipse with the same perimeter and.
Chapter 4 Per forming Particle Analysis © National Instruments Corporation 4-7 IMAQ Vision for LabWindows/CVI User Manual IMAQ_MT_HU_MOMENT_5 Fifth Hu moment IMAQ_MT_HU_MOMENT_6 Sixth Hu mome nt IMAQ.
Chapter 4 Per forming Particle Analysis IMAQ Vision for LabWindows/ CVI User Manual 4-8 ni.com IMAQ_MT_MAX_FERET_DIAMETER_START_Y Y -coordinate of the start of the line segment connecting the tw o per.
Chapter 4 Per forming Particle Analysis © National Instruments Corporation 4-9 IMAQ Vision for LabWindows/CVI User Manual IMAQ_MT_NORM_MOMENT_OF_INERTIA_XXX Normaliz ed moment of inertia in the x dir.
Chapter 4 Per forming Particle Analysis IMAQ Vision for LabWindows/CVI U ser Manual 4-10 ni.com IMAQ_MT_SUM_XX Sum of all x-coordinates squared in the particle IMAQ_MT_SUM_XY Sum of all x-coordinates .
© National Instruments Corporation 5-1 IMAQ Vision for LabWindows/CVI User Manual 5 Performing Machine Vision Ta s k s This chapter describes how to perform many common machi ne vision inspection tas ks.
Chapter 5 Per forming Mac hine Vision T asks IMAQ Vision for LabWindows/ CVI User Manual 5-2 ni.com Figure 5-1 ill ustrates the basic st eps involved in perfor ming machine visio n inspection tas ks. Figure 5-1. Steps to Performing Machine Vision Note Diagram items enclosed with da shed lines are optional steps.
Chapter 5 Per forming Machine Vision T asks © National Instruments Corporation 5-3 IMAQ Vision for LabWindows/CVI User Manual it appears shifted and rotated in the image you need to process. This coordinate system is referred to as the measurement co ordinate system.
Chapter 5 Per forming Mac hine Vision T asks IMAQ Vision for LabWindows/ CVI User Manual 5-4 ni.com Using Edge Detection to Build a Coordinate T ransform You can build a coordinate transform using two edge detection techn iques. Use imaqFindTransformRect() to define a coordinate system using one rectangular region.
Chapter 5 Per forming Machine Vision T asks © National Instruments Corporation 5-5 IMAQ Vision for LabWindows/CVI User Manual b . If you use imaqFindTransformRects() , specify two rectangular objects, each contai ning one separate, straight boundary of the object, as shown in Figure 5-3.
Chapter 5 Per forming Mac hine Vision T asks IMAQ Vision for LabWindows/ CVI User Manual 5-6 ni.com Using Pattern Matching to Bu ild a Coordinate T r ansform You can build a coordinate transform using patt ern matching. Use imaqFindTransformPattern() to define a coordinate system based on the location of a reference feature.
Chapter 5 Per forming Machine Vision T asks © National Instruments Corporation 5-7 IMAQ Vision for LabWindows/CVI User Manual Choosing a Method to Build the Coordinate T ransform Figure 5-4 guides you through cho osing the best method for bui lding a coordinate transform for your appl ication.
Chapter 5 Per forming Mac hine Vision T asks IMAQ Vision for LabWindows/ CVI User Manual 5-8 ni.com Set Search Areas You use ROIs to define search areas in your images and limit the areas in which you perform your processing and inspection. You can define ROIs interactivel y or programmati cally.
Chapter 5 Per forming Machine Vision T asks © National Instruments Corporation 5-9 IMAQ Vision for LabWindows/CVI User Manual Defining Regions Programmatically When you have an automated application, you need to define ROIs programmatically. You can programmatical ly define regions in two ways: • Specify the contours of the R OI.
Chapter 5 Per forming Mac hine Vision T asks IMAQ Vision for LabWindows/CVI U ser Manual 5-10 ni.com Finding Lines or Circles If you want to find points along the edge of an object and find a line describing the edge, use imaqFindEdge() and imaqFindConcentricEdges() .
Chapter 5 Per forming Machine Vision T asks © National Instruments Cor poration 5-11 IMAQ Vision for LabWi ndows/CVI User Manual If you want to find points along a circular edge an d find the circle that best fits the edge, as sho wn in Figure 5-6, use imaqFindCircularEdge() .
Chapter 5 Per forming Mac hine Vision T asks IMAQ Vision for LabWindows/CVI U ser Manual 5-12 ni.com These functions require you to input th e coordinates of the points along the search contour . Use imaqROIProfile() to obtain the coordinates along the edge of each contour in an R OI.
Chapter 5 Per forming Machine Vision T asks © National Instruments Cor poration 5-13 IMAQ Vision for LabWi ndows/CVI User Manual Finding Points Usin g Pattern Matching The pattern matching algorithms.
Chapter 5 Per forming Mac hine Vision T asks IMAQ Vision for LabWindows/CVI U ser Manual 5-14 ni.com Symmetry A rotationally symmetric temp late, shown in Fig ure 5-7a, is less sensi tive to changes in rotation than one that is rotat ionally asymmetric, shown in Figure 5-7b.
Chapter 5 Per forming Machine Vision T asks © National Instruments Cor poration 5-15 IMAQ Vision for LabWi ndows/CVI User Manual Positional Information A template with strong edges in both th e x and y directions is easier to locate.
Chapter 5 Per forming Mac hine Vision T asks IMAQ Vision for LabWindows/CVI U ser Manual 5-16 ni.com the template that are necessary for shift-inv ariant matching. Howe ver, if you want to match the template at any ori entation, use rotation-invariant matching.
Chapter 5 Per forming Machine Vision T asks © National Instruments Cor poration 5-17 IMAQ Vision for LabWi ndows/CVI User Manual Figure 5-11. S electing a Sear ch Area for Grayscale P attern Matching.
Chapter 5 Per forming Mac hine Vision T asks IMAQ Vision for LabWindows/CVI U ser Manual 5-18 ni.com Minimum Contrast The pattern matching algorit hm ignores all image region s in which contrast values fall below a set minimum contrast value. Contrast is the difference between the smallest and largest pi xel va lues in a region.
Chapter 5 Per forming Machine Vision T asks © National Instruments Cor poration 5-19 IMAQ Vision for LabWi ndows/CVI User Manual Using a Ranking Method to V erify Results The manner in which you interp ret the pattern matching algo rithm depends on your application.
Chapter 5 Per forming Mac hine Vision T asks IMAQ Vision for LabWindows/CVI U ser Manual 5-20 ni.com 5. Set the t olerances and p arameters to specify h ow t he algorithm operates at run time using the options parameter of imaqMatchColorPattern() . 6.
Chapter 5 Per forming Machine Vision T asks © National Instruments Cor poration 5-21 IMAQ Vision for LabWi ndows/CVI User Manual Background Information Unique background information in a template improves search performance and accuracy during the grayscale pattern matching phase.
Chapter 5 Per forming Mac hine Vision T asks IMAQ Vision for LabWindows/CVI U ser Manual 5-22 ni.com Defining a Search Area Two equally important factors define the success of a color pattern matching algorithm—accuracy and speed . You can define a search area to reduce ambiguity in the search proce ss.
Chapter 5 Per forming Machine Vision T asks © National Instruments Cor poration 5-23 IMAQ Vision for LabWi ndows/CVI User Manual The time required to locate a pattern in an image depends on both the template size and the search area. By reducing the search area or increasing the template size, you can reduce the required search time.
Chapter 5 Per forming Mac hine Vision T asks IMAQ Vision for LabWindows/CVI U ser Manual 5-24 ni.com Choose from the followi ng search strategies: • IMAQ_CONSERVATIVE —Uses a very small ste p size, the least amount of subsampling, and all the color in formation present in the tem plate.
Chapter 5 Per forming Machine Vision T asks © National Instruments Cor poration 5-25 IMAQ Vision for LabWi ndows/CVI User Manual Rotation Angle Ranges Refer to the Setting Matchin g Parameters a nd Tolerances section of this chapter for informati on about rotation angle ran ges.
Chapter 5 Per forming Mac hine Vision T asks IMAQ Vision for LabWindows/CVI U ser Manual 5-26 ni.com 6. T est the color location algorithm on test images using imaqMatchColorPattern() . 7. V erify the results using a ranking method. Y ou can sav e the template image using imaqWriteV isionFile() .
Chapter 5 Per forming Machine Vision T asks © National Instruments Cor poration 5-27 IMAQ Vision for LabWi ndows/CVI User Manual Analytic Geometr y Measurements Use the following functions to make ge.
Chapter 5 Per forming Mac hine Vision T asks IMAQ Vision for LabWindows/CVI U ser Manual 5-28 ni.com Use imaqFindLCDSegments() to calculate the R OI around each digit in an LCD or LED. T o find the area of each digit, all the segments of the indicator must be activ ated.
Chapter 5 Per forming Machine Vision T asks © National Instruments Cor poration 5-29 IMAQ Vision for LabWi ndows/CVI User Manual The following code sample provides an example of a typical classif ication application. ClassifierSession* session; Image* image; ROI* roi; char* fileName; // The classifier fi le to use.
Chapter 5 Per forming Mac hine Vision T asks IMAQ Vision for LabWindows/CVI U ser Manual 5-30 ni.com Reading Barcodes Use barcode reading functions to read values encoded int o 1D barcodes, Data Matrix barcodes, and PDF417 barcodes.
Chapter 5 Per forming Machine Vision T asks © National Instruments Cor poration 5-31 IMAQ Vision for LabWi ndows/CVI User Manual By default, imaqReadDataMatrixBarcode() assumes the barcode cells are square. If the barcodes you need to read hav e round cells, set the cellShape element of the options paramet er to IMAQ_ROUND_CELLS .
Chapter 5 Per forming Mac hine Vision T asks IMAQ Vision for LabWindows/CVI U ser Manual 5-32 ni.com Use the following functions to ov erlay search re gions, inspection results, and other information, such as text and bitmaps. • imaqOverlayPoints() — Overlays points on an image.
Chapter 5 Per forming Machine Vision T asks © National Instruments Cor poration 5-33 IMAQ Vision for LabWi ndows/CVI User Manual The following list contains the kinds of information you can overlay with the pre vious functions except imaqFindPattern() , imaqCountObjects() , and imaqFindTransformPatte rn() .
© National Instruments Corporation 6-1 IMAQ Vision for LabWindows/CVI User Manual 6 Calibrating Images This chapter describes how to calibrate yo ur imaging system, save calibration information , and attach calibration in formation to an image. After you set u p your imaging system , you may want to cal ibrate your system.
Chapter 6 Calibrating Images IMAQ Vision for LabWindows/ CVI User Manual 6-2 ni.com Refer to Chapter 5, Performing Machine Vision Tasks , fo r more information about applying calibratio n information before making measurements.
Chapter 6 Calibr ating Images © National Instruments Corporation 6-3 IMAQ Vision for LabWindows/CVI User Manual Defining a Reference Coordinate System To express measurements in real-w orld units, you need to d efine a coordinate system in the imag e of the grid.
Chapter 6 Calibrating Images IMAQ Vision for LabWindows/ CVI User Manual 6-4 ni.com Figure 6-3. A Calibration Grid and an Image of the Grid Note If you specify a list of points instead of a grid for the calibration process, the software def ines a default coordinate system, as follo ws: 1.
Chapter 6 Calibr ating Images © National Instruments Corporation 6-5 IMAQ Vision for LabWindows/CVI User Manual Figure 6-4. Defining a Coordinate System Learning Calibration Information After you define a calibration grid and reference axis, acquire an image of the grid using the current imaging se tup.
Chapter 6 Calibrating Images IMAQ Vision for LabWindows/ CVI User Manual 6-6 ni.com Specifying Scaling Factors Scaling factors are the real-world distances between the dots in the calibration grid in the x and y direction s and the units in which the distances are measured.
Chapter 6 Calibr ating Images © National Instruments Corporation 6-7 IMAQ Vision for LabWindows/CVI User Manual Choose the perspecti ve projection algo rithm when your system exhibits perspecti ve errors only .
Chapter 6 Calibrating Images IMAQ Vision for LabWindows/ CVI User Manual 6-8 ni.com If the learning process returns a learni ng score below 600, try the follo wing: 1. Make sure your grid co mplies with t he guidelines listed in the Defining a Calibration Tem plate section of this chapter .
Chapter 6 Calibr ating Images © National Instruments Corporation 6-9 IMAQ Vision for LabWindows/CVI User Manual Simple Calibration When the axis of your camera is perpendicular to the image plane and lens distortion is negligibl e, use simple calibration.
Chapter 6 Calibrating Images IMAQ Vision for LabWindows/CVI U ser Manual 6-10 ni.com Save Calibration Information After you learn th e calibration informatio n, you can save it so that yo u do not have to relearn the informatio n for subsequent processing.
© National Instruments Corporation A-1 IMAQ Vision for LabWi ndows/CVI User Manual A T echnical Support and Professional Ser vices Visit the following sections of the National Instruments Web site at ni.com for technical support an d professional services: • Support —Online technical support resources at ni.
© National Instruments Corporation G-1 IMAQ Vision for LabWind ows/CVI User Manual Glossar y Numbers 1D One-dimensional. 2D T wo-dimensional. 3D Three-dimensional. A AIPD The National Instrument s internal image file format used for saving complex images and calib ration information associ ated with an image (extension APD).
Glossary IMAQ Vision for LabWindows/ CVI User Manual G-2 ni.com barycenter The grayscale value repres enting the centroid of the range of an image’ s grayscale v alues in the image histogram. binary image An image in which the objects usually have a pix el intensity of 1 (or 255) and the background has a pixel intensity of 0.
Glossary © National Instruments Corporation G-3 IMAQ Vision for LabWind ows/CVI User Manual C caliper (1) A function in the NI V ision Assistant and in NI V ision Buil der for Automated Inspection th.
Glossary IMAQ Vision for LabWindows/ CVI User Manual G-4 ni.com connecti vity-4 O nly pixels adjacent in the horizon tal and v ertical direc tions are considered neighbors.
Glossary © National Instruments Corporation G-5 IMAQ Vision for LabWind ows/CVI User Manual edge steepness The number of pixels that corr esponds to the slope or transition area of an edge. energy center The center of mass of a grayscale image. See also center of mass .
Glossary IMAQ Vision for LabWindows/ CVI User Manual G-6 ni.com gradient filter An edge detection algorithm that extracts the contours in gray-le vel v alues. Gradient filters include the Pr e witt and Sobel filters. gray lev el The brightness of a pixel in an image.
Glossary © National Instruments Corporation G-7 IMAQ Vision for LabWind ows/CVI User Manual hit-miss function Locates objects in the image similar to the patt ern defined in the structuring element. HSI A color encoding scheme in hue, saturation, and intensity .
Glossary IMAQ Vision for LabWindows/ CVI User Manual G-8 ni.com image enhancement The process of improving the quality of an i mage that you acqu ire from a sensor in terms of signal-to-noise ratio, imag e contrast, edge definition, and so on. image file A f ile containing pixel data and additional information about the image.
Glossary © National Instruments Corporation G-9 IMAQ Vision for LabWind ows/CVI User Manual intensity calibration A ssigns user -defined quantities such as optical densities or concentrations to the gray-le vel v alues in an image. intensity profile The gray-lev el distribution of the pix els along an R O I in an image.
Glossary IMAQ Vision for LabWindow s/CVI User Manual G-10 ni.com line gauge Measures the distance between selected edges with hig h-precision subpixel accuracy along a line in an image. For e xample, this function can be used to measure distances between points and edges.
Glossary © National Instruments Cor poration G-11 IMAQ Vision for LabWindows/CVI User Manu al luminance See luma . LUT Lookup table. A table containing v alu es used to transform the gray-le v el v alues of an image. For each gray -lev el v alue in the image, the corresponding new v alue is obtained from the lookup table.
Glossary IMAQ Vision for LabWindow s/CVI User Manual G-12 ni.com N neighbor A pixel whose v alue af fects the v alue of a nearb y pix el when an image is processed.
Glossary © National Instruments Cor poration G-13 IMAQ Vision for LabWindows/CVI User Manu al of fset The coordinate positi on in an imag e where you want to place the origin of another image. Setting an offset is useful when performing mask operations.
Glossary IMAQ Vision for LabWindow s/CVI User Manual G-14 ni.com PNG Portable Network Graphic. An image file format for storing 8-bit, 16-bit, and color images with lossless compre ssion.
Glossary © National Instruments Cor poration G-15 IMAQ Vision for LabWindows/CVI User Manu al R OI Region of inter est. (1) An area of the image that is graphically selected from a windo w displaying the image. This area can be used focus further processing.
Glossary IMAQ Vision for LabWindow s/CVI User Manual G-16 ni.com spatial filters Alter the intensity of a pixel relative to variations in intensities of its neighboring pixels. Y ou can use these filters for edge detection, image enhancement, noise reduction, smoothing, and so forth.
Glossary © National Instruments Cor poration G-17 IMAQ Vision for LabWindows/CVI User Manu al V v alue The grayscale intensity of a color pixel computed as the av erage of the maximum and min imum red, green, an d blue v alues of that pixel. VI V irtual Instrument.
© National Instruments Corporation I-1 IMAQ Vision for LabWindows/CVI User Manual Index Numerics 1D barcodes, reading, 5-30 2D arrays, converting to images, 2-5, 2-7 A acquiring, images, 2-5 analyzin.
Index IMAQ Vision for LabWindows/ CVI User Manual I-2 ni.com color information learning, 3-9 specifying, 3-9 color location, using to find points, 5-25 color representation sensitivity, specifying, 3-.
Index © National Instruments Corporation I-3 IMAQ Vision for LabWindows/CVI User Manual error maps, learning, 6-8 examples (NI resources), A-1 external windows, displaying im ages, 2-7 extracting, pl.
Index IMAQ Vision for LabWindows/ CVI User Manual I-4 ni.com improving binary images, 4-2 improving sharpn ess of transitions, 2-10 inspecting, 2-8 learning color info rmation, 3-9 learning the color .
Index © National Instruments Corporation I-5 IMAQ Vision for LabWindows/CVI User Manual N National Instruments support and services, A-1 NI Vision Assistant, x NI Vision Builder for Automated I nspec.
Index IMAQ Vision for LabWindows/ CVI User Manual I-6 ni.com search algorithm, testing, 5-18, 5-25 search areas, 5-10 defining, 5-16, 5-22 ROIs, defining search areas, 5-8 search strategies, se lectin.
Un punto importante, dopo l’acquisto del dispositivo (o anche prima di acquisto) è quello di leggere il manuale. Dobbiamo farlo per diversi motivi semplici:
Se non hai ancora comprato il National Instruments IMAQ Vision for LabWindows TM /CVI è un buon momento per familiarizzare con i dati di base del prodotto. Prime consultare le pagine iniziali del manuale d’uso, che si trova al di sopra. Dovresti trovare lì i dati tecnici più importanti del National Instruments IMAQ Vision for LabWindows TM /CVI - in questo modo è possibile verificare se l’apparecchio soddisfa le tue esigenze. Esplorando le pagine segenti del manuali d’uso National Instruments IMAQ Vision for LabWindows TM /CVI imparerai tutte le caratteristiche del prodotto e le informazioni sul suo funzionamento. Le informazioni sul National Instruments IMAQ Vision for LabWindows TM /CVI ti aiuteranno sicuramente a prendere una decisione relativa all’acquisto.
In una situazione in cui hai già il National Instruments IMAQ Vision for LabWindows TM /CVI, ma non hai ancora letto il manuale d’uso, dovresti farlo per le ragioni sopra descritte. Saprai quindi se hai correttamente usato le funzioni disponibili, e se hai commesso errori che possono ridurre la durata di vita del National Instruments IMAQ Vision for LabWindows TM /CVI.
Tuttavia, uno dei ruoli più importanti per l’utente svolti dal manuale d’uso è quello di aiutare a risolvere i problemi con il National Instruments IMAQ Vision for LabWindows TM /CVI. Quasi sempre, ci troverai Troubleshooting, cioè i guasti più frequenti e malfunzionamenti del dispositivo National Instruments IMAQ Vision for LabWindows TM /CVI insieme con le istruzioni su come risolverli. Anche se non si riesci a risolvere il problema, il manuale d’uso ti mostrerà il percorso di ulteriori procedimenti – il contatto con il centro servizio clienti o il servizio più vicino.
