1、三維信息獲取與重構技術,實體三維信息獲取與重構,Rendering,Shape,Lighting and Reflectance,Motion,Computer Vision,Dept. of Communication Eng.,結構光法背景,C1,一個圖像點對應著多個空間點（一條直線無法確定一個點）,雙攝像機可確定空間點 （兩條直線相交可確定一個點）,立體視覺,Computer Vision,Dept. of Communication Eng.,結構光法背景,C1,立體視覺的關鍵,兩幅圖像中對應點的確定,C2,Computer Vision,Dept. of Communication

2、Eng.,結構光法背景,C1,對應點的確定,C2,Computer Vision,Dept. of Communication Eng.,結構光法背景,結構光 系統(tǒng)構成,投影儀代替攝像機 投射特定光源解決對應問題,Computer Vision,Dept. of Communication Eng.,結構光法基本原理,相似三角形 平行直線,推導,結構光系統(tǒng)建模,相似三角形,平行直線,Computer Vision,Dept. of Communication Eng.,結構光法標定,結構光系統(tǒng)標定,相似三角形,平行直線,標定參數(shù)： 基線b 攝像機焦距f 投影儀投影角,Computer Visi

3、on,Dept. of Communication Eng.,結構光法編碼光,光源設計,各種編碼方式,Laser Triangulation,Depth from ray-plane triangulation,Object,(x,y),In order to obtain a full range image, what is necessary?,a system must have some methods of determining which stripe is which,Slow, robust,Fast, fragile,Color direct coding,Colored

4、 dots Davies 96 A gray wedge Carrihill 85,*Reflectivity assumption Eg. Fails if the surface is textured,Spatial neighborhood,Boyer 87 Proesmans 96,*Spatial coherence（空間相關） assumption Eg. Fails if surface contains discontinuities,0 1,Time-multiplexing,Sato 87,*Temporal coherence（時間相關） assumption Eg.

5、Take several frames to compute depth,Time-multiplexing,Pattern 1,Pattern 2,Pattern 3,隨時間投影,該像素的編碼值: 1010010 用于識別該點的對應關系,Designing a Code,Project Code,Capture Images,Find Boundaries,Match Boundaries,Decode,Compute Range,Designing a Code,Design a code to make tracking possible: Do not allow two spatia

6、lly adjacent ghosts Do not allow two temporally adjacent ghosts,t,Graph (for 3 frames):,Edges: boundaries (over time),Designing a Code,Designing a Code,Graph (for 3 frames):,56 edges in graph maximal-length traversal has 64 boundaries (65 stripes),Matching Stripe Boundaries,Project Code,Capture Imag

7、es,Find Boundaries,Match Boundaries,Decode,Compute Range,Even if number of ghosts isminimized, matching is not easy,?,Calibration,y,x,O,f,P,X(u,v,f),CP(Camera plane),X(x,y,z),L,S(Light plane),PP(Projector plane),X0,z,q,Calibration n,P,Results,projector,CCD,Cup,Results,Video frames,Stripe boundaries,Results,Multiple views by a free-mobile camera,Multiple views by a free-mobile camera,“Wa Wa”,“Athlete ”,Multiple views by a free-