SL A Tordivel - Thor Vollset -Stereo Vision and structured illumination creates dense 3D Images Page 1

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1 Tordivel ASTORDIVEL Scorpion Vision Software Scorpion Stinger are trademarks SL A AS - Scorpion Visionand 8 and 3DMaMa Tordivel ASof Tordivel AS Page 1

2 Stereo Vision and structured illumination creates dense 3D Images Thor Vollset CEO Tordivel AS Monday :00 11:20 h LASER World of PHOTONICS 2015 Forum Halle A2 Optical Metrology and Imaging Page 2

3 Tordivel AS, Scorpion Vision Software and Scorpion Stinger Components Tordivel is located in Oslo, Norway Scorpion Vision Software Hand-made in Norway Based on Industry Standards Complete 2D and 3D Support No programming Python Language Support for OpenCV 3.0 First version in now version XI Scorpion Stinger Components Scorpion Embedded PC Scorpion 2D and 3D Stinger Camera Integrated White and IR LED illumination Page 3

4 3D Stereo Vision Viewing an object from two positions just like the eyes of a person The displacement between the two images contains depth information The practical challenge is to find the corresponding features in the two images Occlusion and and perspective can be a challenge "Epipolar Geometry1" by ZooFari Own work. Licensed under Public Domain via Wikimedia Commons - Page 4

5 Locating features in two images By locating the same feature in two images the position (x,y,z) can be calculated Locating multiple points to create a 3D object pose (x,y,z, rx,ry,rz) Subpixel resolution may improve the accuracy by a factor of 5x to 20x. Critical in serious 3D Stereo Vision Page 5

6 Accuracy in Stereo Vision The typical resolution for object location within a FOV 800 x 600 x 500 mm is better than 1 mm in x, y and 1 to 2 mm in z. The resolution and accuracy must be verified in each application and is determined by the following elements: Size of Picking Area Size of object to be picked or located Camera Resolution Camera Distance to the picking Baseline between the stereoscopic camera The Z resolution can be defined by the following formula: Zres=PixelResolution / SubPixelResolutionFactor * (Distance / Baseline) PixelResolution is the size of each pixel SubPixelResolutionFactor is typically 10 - CRITICAL - CAMERACALIBRATION the factor can be bigger if the objects or feature to be located is large Distance is the distance from the camera to the object Baseline is the distance between the two cameras in the stereo-pair Page 6

7 Dense 3D Stereo Vision What is needed to create a dense 3D image using stereo-vision? Two 2D images with texture Accurate 3D Camera Calibration Intermediate tool and results ImageRectify --> Rectified Images --> BlockMatcher --> DisparityMap Output 3D Image ---> HeightMap How fast is this : from 50 ms to 2.0 seconds Page 7

8 RPP - Random Pattern Projector The following describes an RPP Laser Wavelength : Red 660 nm or IR 830 nm Random dots to Opening angle 30 to 45 degrees Power 50 mw to 250 mw Without texture no 3D information The purpose of the RPP laser is to guarantee texture in the 2D image. Page 8

9 Application - 3D Robot Vision Generic 3D Depallitizing of large objects: Objects are defined by dimensions in 3D Page 9

10 Application - Saugage Picking Page 10

11 3D in 2D images Background Once the object plane is located in the 3D image we can move to the 3D calibrated 2D image object plane The 2D image contains a lot more information than the 3D image - 3D resolution is limited by the RPP dot number and size 3D Robot Vision Locating Flat Parts Page 11

12 Locating multiple objects in 3D Multiple objects are located and segmented in the dense 3D image generated by the RPP stereo images using the STC-0090-FindPlanesDMap3D RPP 3D Image The pose (x,y,z,rx,ry,rz) of the objects are calculated. This pose can be used to create and 3D object reference - the basis for 3D in 2D Multiple 3D Part Location Page 12

13 3D in 2D - working in 3DObjectRef Using the object pose a 3D reference is easily created for each object plane. Resampled Part Once you hold the object in your hand by the 3D Object Reference the term Subpixel 3D in 2D images make sense - this is so valuable 3D Object Reference Page 13

14 3D Stereo Vision Summary Extracting 3D features from 2D images is fast, robust and a natural extension to 2D Machine Vision. 3D Dense Image Creation is wonderful and extremely powerful - structured light and RPP makes the 3D image creation more robust. Using strobed high power IR led and lasers makes 3D image creation robust to ambient light variations. 3D Stereo Vision is an important element in the future of Machine Vision. It supplement the 3D Scanner in a natural manner. Multiple 3D Cameras are needed to create a 360 degrees 3D Model 3D Stereo Vision works on moving objects :) Page 14

15 Tordivel ASTORDIVEL Scorpion Vision Software Scorpion Stinger are trademarks SL A AS - Scorpion Visionand 8 and 3DMaMa Tordivel ASof Tordivel AS Page 15