1. Tour Into the Picture: Using a Spidery Mesh to Make Animation from a Single Image Youichi Horry, Ken-ichi Anjyo, and Kiyoshi Arai SIGGRAPH 1997 presented by Dave Edwards 10/31/2000

2. A Unique Problem zCan we create animation from a single image? yPaintings ySingle photographs zExtremely difficult for a computer yNo information for depth or 3D structure zNot as difficult for a human brain

3. A Unique Solution zA system that allows humans and computers to do what they do best yHuman supplies 3D scene information yComputer supplies efficient interface for: xSpecifying vanishing points xDifferentiating foreground & background xBuilding the scene with simple polygons

4. Tour Into the Picture (TIP) zSystem that allows efficient specification of 3D information zBasically, construct a diorama-like model of the scene ySimple, generic representation x5 (or fewer) polygons for background xSmall number of polygons for each foreground object

5. Overview zScene modeling ySeparate foreground & background ySpecify a vanishing point yModel the background yModel foreground objects zScene animation & rendering zConclusions zDemo

6. Scene Modeling zAssumptions yScene is basically a box ySides of the box are orthogonal to each other yVirtual camera may not be tilted xView up vector is perpendicular to “floor”

7. Separate Fore- & Background zStart with a single image:

8. Separate Fore- & Background zCreate two images with standard image editor zForeground mask: yOne gray region for each object yGrayscale map of alpha values zBackground image: yOriginal image w/o foreground yUse neighboring pixels to fill gaps

9. Separate Fore- & Background zExample foreground mask:

10. Separate Fore- & Background zExample background image:

11. Specify a Vanishing Point zUse a “spidery mesh” yInner rectangle xSpecifies “rear wall” of scene yRadial perspective lines xSpecify the location of the vanishing point xShould be parallel to guide lines in the picture zInterface allows rapid changes in the mesh

12. Specify a Vanishing Point zExample of Interface:

13. Model the Background zPartition the background into 5 pieces: yRear wall (inner rectangle) yFloor (y = 0) yCeiling yLeft Wall yRight Wall zCalculate 3D coords for the vertices of the box

14. Model the Background zExample of background model:

15. Model the Foreground zForeground objects defined by mask zConstruct polygon model of each object yMust be orthogonal to one side of the box yCalculate 3D coords for corners of polygon

16. Model the Foreground zMore complex objects can be made of multiple polygons yEach additional polygon must be connected to the previous one yThis allows the system to determine its 3D coordinates

17. Model the Foreground zExample of foreground model:

18. Scene Animation & Rendering zCamera transformations: yRotation (change view-plane normal) yTranslation yZoom (move viewpoint forward) yChange view angle yLook around (orbit about central object)

19. Scene Animation & Rendering zWe know 3D coordinates for points in the scene zGiven a pixel to render, find its 3D image in the original scene zApply smoothing for the background zApply alpha blending for the foreground objects

20. Conclusions zTIP is very flexible yIn general, assumptions do not create severe constraints yGeneric foreground/background model works with many types of images zInterface is (fairly) simple & intuitive, even in the demo version yIt could use a little internationalization...

21. Future Possibilities zHandle two-point perspective drawings zAllow multiresolution images zImprove the model for foreground objects

22. Demonstration