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1 NIWeek Vision Summit August 2-3, 2011 Austin, Texas

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Presentation on theme: "1 NIWeek Vision Summit August 2-3, 2011 Austin, Texas"— Presentation transcript:

1 1 NIWeek Vision Summit August 2-3, 2011 Austin, Texas

2 2 Breaking New Ground with Vision Inspection Systems Dr. Dan Milkie Senior Developer Coleman Technologies, Inc. NIWeek Vision Summit August 2–3, 2011 Austin, Texas

3 What if theres no existing solution? Prototyping tips Planning guide Implementation Imaging algorithms – Finding small defects – 3D laser triangulation Final lessons 3

4 About us 16 year National Instruments Alliance Partner Basler Vision System Integrator NI Certified Developers & NI Professional Instructors Advanced engineering & science degrees 4

5 Vision Applications 5 Industrial Research – Dinnerware defect detection system – Dinnerware color pattern inspection system – Robotic seed germination classifier – High-speed seed counting system – Laser drilling inspection – Thin film defect identification – Mirror defect detection – PCB contact pad inspection system – Color tablet tracking – Particle size analysis (powders) – Particle size analysis (liquid suspension) – Glass rod inspection – Well plate inspection system – Bio-sample thermal imaging – Wellplate imaging system – Crystal finder/classifier – Biaxial tissue tester – Two-photon microscopy Plate Inspection System

6 The Challenge Dinnerware Inspection Many different dishes 1 dish per second Most difficult defect: – White bumps on white plates 6 Defects

7 Can we image the defects? Prototype with what you have (or loaners) – Area-scan camera (GigE) – Lighting Directional : Desk lamp Broad sources : Room lights, diffusers – NI Vision Development Module Optimize lighting & camera placement – Tip : Replace camera with your eye 7

8 Okay, I see the defects, but can the computer? 8 Start with NI Vision Assistant – Fastest way to test processing functions – Estimate time using the Performance Meter – Quickly turn scripts into LabVIEW VIs

9 Okay, I see the defects, but can the computer? Start with NI Vision Assistant – Fastest way to test processing functions – Estimate time using the Performance Meter – Quickly turn scripts into LabVIEW VIs 9

10 Proof of Principle Are you confident in your plan yet? If not, prototype in LabVIEW! – Combine acquisition and analysis – Tip : Use tester with fresh data or saved image sets Practice good coding style – Prototypes Final version – Good code encourages trying new ideas – Documentation should be automatic 10

11 Going for it Ready to build your system? Know your test set, criteria Balance goals with sliding scales instead of all-or-nothing Solve most pressing issues first – Example : Our 1 st generation machine tested 1 plate type (their most popular) and only 4 defect types 11 Time $$ Accuracy

12 Modular, Modular, Modular Independent Stations 1.Bottom view 2.3D imaging 3.Top view Lesson learned : Needed to add baffles Found interference between stations Changed how plates cross gaps Vibration issues 12 NI PCIe-1430 Dual CameraLink NI PCIe-1430 Dual CameraLink NI PCIe-8235 4x GigE NI PCIe-8235 4x GigE PC 123

13 Small defect imaging First version : Next version: Defects show up as dark spots: 13 LED light LED light Line scan Camera Glancing Angle Transmission

14 Small Defects are Hard to Find! Problems : – Defects are small, low contrast – Large gradients in image – Plate-to-plate variations – Image size (8MP!) – Must process in < 0.5 second Solution: – A custom pixel-by-pixel threshold for each image. 14 Defect!

15 Step 1 : Unwrap Image Problem : We just need rim pixels Use image masks? – Longer process times – Still have large images Solution : IMAQ Unwrap 8M pixel square -> 1.5M pixel strip Aligns gradients, rim transitions in one direction 15

16 Step 2 : Create Custom Golden Master What should this image look like if it were perfect? Remove defects using median smoothing – Tip : Use X Size >> Y Size to preserve gradients & edges – Performance Boost : Reduce image resolution, Smooth, then Resample back to original size. 16 Unwrapped Original Median Smoothed Golden Master Defect Defect Removed!

17 Step 3 : Pixel-by-pixel Threshold 17 Golden Master Results Subtract a constant to set a lower threshold. Original Defect Found! Threshold original image using IMAQ Compare

18 Benefits of Pixel-by-pixel Thresholds Works with: – Gradients, edges, speckle, large dynamic contrasts Every image checks against itself – Robust against image-image variations, changing lighting conditions Fast (<100ms for 1.5MP) – Limited by smoothing performance 18

19 3D Imaging Simple inspection for geometric errors – Gouges, bulges, warp 19 Warp examples

20 Laser Triangulation 20 Laser Line Laser Line Area Camera Area Camera Original Threshold applied

21 Convert pixels to height 21 With a little more geometry, we can also correct for perspective : WD Laser Line Laser Line Area Camera Area Camera H dy Height =

22 3D Laser Height Measurement 22 Each camera frame = 1 cross section (per laser line) – Tip : Add multiple laser lines for more cross sections 250 um cross section resolution (100 FPS @ 1 per sec) – Tip : Reduce ROI for fastest frame rates 100 um height resolution

23 Completed system Fast development with NI tools: – Completed in < 3 months Reliable – Inspected over 1 million dishes Multiple follow-up systems 23

24 Conclusions Invest in good prototyping practices Prepare for unknown hurdles – Use modular, flexible architectures in hardware, layout, software Defect finding algorithm – Pixel-by-pixel thresholds Simple 3D laser scanner – Inexpensive, easy to setup 24

25 Questions? 25

26 26 NIWeek Vision Summit August 2–3, 2011 Austin, Texas Keynotes Industry Keynote: How NI Technology Powers the Space ElevatorLaserMotive Tuesday, August 2 1:00-2:00 Academic Keynote: Industry Trends and Intelligent Production Systems of the Future Interdisciplinary Imaging and Vision Institute, RWTH Aachen University Wednesday, August 3 1:00-2:00 Tuesday, August 2 3D Vision and the KinectNational Instruments10:30-11:30 Wacky Optical Tricks for Machine VisionGE Global Research Center2:15-3:15 Panel Discussion: Latest in Camera Technologies Cyth Systems Basler Vision Technologies Pleora Technologies Toshiba TELI 3:30-4:30 Machine Vision and Industrial Robotics: From Design Concepts to Factory Floor DeploymentImagingLab4:45-5:45 Wednesday, August 3 Precision MetrologyNational Instruments10:30-11:30 Is LabVIEW FPGA Right for My Vision Application?National Instruments2:15-2:45 Autofocus System for an EllipsometerNanometrics Inc.2:45-3:15 Developing a Quality Inspection Method for Selective Laser Melting of Metals Using a High- Speed NIR Camera Katholieke Universiteit Leuven3:30-4:00 Web Inspection of Optical and Medical FibersAdsys Controls Inc.4:00-4:30 Breaking New Ground with Vision Inspection SystemsColeman Technologies Inc.4:45-5:15 Development of a Digitally Multiplexed Bioassay Reader with Magnetic Bead TechnologyMoviMED4:15-4:45

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