结构光3D扫描原理必看.pptx

Computer VisionSpring 2006 15-385,-685Instructor:S.NarasimhanWean 5403T-R 3:00pm 4:20pmLecture#17Structured Light+Range ImagingLecture#17(Thanks to Slides from Levoy,Rusinkiewicz,Bouguet,Perona)3D ScanningStructured Light ReconstructionAvoid problems due to correspondenceAvoid problems due to surface appearanceMuch more accurateVery popular in industrial settingsReading:Marc Levoys webpages(Stanford)Katsu Ikeuchis webpages(U Tokyo)Peter Allens webpages(Columbia)Stereo TriangulationIJCorrespondence is hard!IJStructured Light TriangulationCorrespondence becomes easier!Structured Light Any spatio-temporal pattern of light projected on a surface(or volume).Cleverly illuminate the scene to extract scene properties(eg.,3D).Avoids problems of 3D estimation in scenes with complex texture/BRDFs.Very popular in vision and successful in industrial applications(parts assembly,inspection,etc).Light Stripe Scanning Single StripeCameraSourceSurfaceLight planeOptical triangulationProject a single stripe of laser lightScan it across the surface of the objectThis is a very precise version of structured light scanningGood for high resolution 3D,but needs many images and takes timeTriangulationProject laser stripe onto objectObjectObjectLaserLaserCameraCameraLight PlaneCameraCameraTriangulationDepth from ray-plane triangulation:Intersect camera ray with light planeLaserLaserObjectObjectLight PlaneImage PointExample:Laser scannerCyberware face and head scanner+very accurate 0.01 mm more than 10sec per scanDigital Michelangelo Projecthttp:/graphics.stanford.edu/projects/mich/Example:Laser scannerPortable 3D laser scanner(this one by Minolta)Faster Acquisition?Project multiple stripes simultaneouslyCorrespondence problem:which stripe is which?Common types of patterns:Binary coded light striping Gray/color coded light stripingBinary CodingPattern 1Pattern 2Pattern 3Projected over timeExample:3 binary-encoded patterns which allows the measuring surface to be divided in 8 sub-regions Faster:stripes in images.Binary CodingAssign each stripe a unique illumination codeover time Posdamer 82SpaceSpaceTimeTimeBinary CodingPattern 1Pattern 2Pattern 3Projected over timeExample:7 binary patterns proposed by Posdamer&AltschulerCodeword of this pxel:1010010 identifies the corresponding pattern stripeMore complex patternsZhang et alWorks despite complex appearancesWorks in real-time and on dynamic scenes Need very few images(one or two).But needs a more complex correspondence algorithmContinuum of Triangulation MethodsSlow,robustSlow,robustFast,fragileFast,fragileMulti-stripeMulti-stripeMulti-frameMulti-frameSingle-frameSingle-frameSingle-stripeSingle-stripe3D Acquisition from ShadowsBouguet-Perona,ICCV 983D Model Acquisition Pipeline3D Scanner3D Scanner3D Model Acquisition Pipeline3D Scanner3D ScannerView PlanningView Planning3D Model Acquisition Pipeline3D Scanner3D ScannerAlignmentAlignmentView PlanningView Planning3D Model Acquisition Pipeline3D Scanner3D ScannerAlignmentAlignmentMergingMergingView PlanningView Planning3D Model Acquisition Pipeline3D Scanner3D ScannerAlignmentAlignmentMergingMergingDone?Done?View PlanningView Planning3D Model Acquisition Pipeline3D Scanner3D ScannerAlignmentAlignmentMergingMergingDone?Done?View PlanningView PlanningDisplayDisplayReal-Time 3D Model AcquisitionNext ClassPolyhedral Objects and Line DrawingReading Notes