结构光3D扫描原理课件-经典必看.ppt

1、Computer Vision,Spring 2019 15-385,-685Instructor:S.NarasimhanWean 5403T-R 3:00pm 4:20pmLecture#17,Structured Light+Range ImagingLecture#17,(Thanks to Slides from Levoy,Rusinkiewicz,Bouguet,Perona),3D Scanning,Structured Light Reconstruction,Avoid problems due to correspondenceAvoid problems due to

2、surface appearanceMuch more accurateVery popular in industrial settingsReading:Marc Levoys webpages(Stanford)Katsu Ikeuchis webpages(U Tokyo)Peter Allens webpages(Columbia),Stereo Triangulation,I,J,Correspondence is hard!,I,J,Structured Light Triangulation,Correspondence becomes easier!,Structured L

3、ight,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,inspecti

4、on,etc).,Light Stripe Scanning Single Stripe,Camera,Source,Surface,Light plane,Optical 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 tim

5、e,Triangulation,Project laser stripe onto object,Object,Light Plane,Triangulation,Depth from ray-plane triangulation:Intersect camera ray with light plane,Laser,Object,Light Plane,Image Point,Example:Laser scanner,Cyberware face and head scanner,+very accurate 0.01 mm more than 10sec per scan,Digita

6、l Michelangelo Projectgraphics.stanford.edu/projects/mich/,Example:Laser scanner,Portable 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 cod

7、ed light striping,Binary Coding,Pattern 1,Pattern 2,Pattern 3,Projected over time,Example:3 binary-encoded patterns which allows the measuring surface to be divided in 8 sub-regions,Faster:stripes in images.,Binary Coding,Assign each stripe a unique illumination codeover time Posdamer 82,Space,Time,

8、Binary Coding,Pattern 1,Pattern 2,Pattern 3,Projected over time,Example:7 binary patterns proposed by Posdamer&Altschuler,Codeword of this pxel:1010010 identifies the corresponding pattern stripe,More complex patterns,Zhang et al,Works despite complex appearances,Works in real-time and on dynamic sc

9、enes,Need very few images(one or two).But needs a more complex correspondence algorithm,Continuum of Triangulation Methods,Slow,robust,Fast,fragile,3D Acquisition from Shadows,Bouguet-Perona,ICCV 98,3D Model Acquisition Pipeline,3D Scanner,3D Model Acquisition Pipeline,3D Scanner,3D Model Acquisition Pipeline,3D Scanner,3D Model Acquisition Pipeline,3D Scanner,3D Model Acquisition Pipeline,3D Scanner,3D Model Acquisition Pipeline,3D Scanner,Real-Time 3D Model Acquisition,Next Class,Polyhedral Objects and Line DrawingReading Notes,