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Image Based Rendering

Image Based Rendering. Light Field. Gershun in 1936 An illuminated objects fills the surrounding space with light reflected of its surface, establishing the object ’ s “ light field ” Adelson and Bergen 1991 Plenoptic Function. Plenoptic Funtions.

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Image Based Rendering

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  1. Image Based Rendering

  2. Light Field • Gershun in 1936 • An illuminated objects fills the surrounding space with light reflected of its surface, establishing the object’s “light field” • Adelson and Bergen 1991 • Plenoptic Function

  3. Plenoptic Funtions • An observer at any point in space (x,y,z) and any moment in time (t) can look in any direction(θ,ǿ) and record the incoming light intensity Φ at all visible wavelength λ • Φ= Φ(x,y,z,t, θ,ǿ, λ) • Φ is the radiation’s spectral intensity, a scalar value denotes the incoming light’s power per unit per area per solid angle per unit wavelength interval

  4. Image Based Rendering • If Φis known, any view of the scene can be reconstructed • IBR an approach to computer-generated 2D-views of natural 3D-scenes • Approximation of the plenoptic functions from a number of conventional images

  5. IBR Topics • View-Dependent Texture Mapping • Hybrid Geometry and Image Based Rendering • Delta Tree Representation • Multiple-Centre-of-Projection Images • Layered Depth Images • Sprites with Depth • Plenoptic Modeling and Environment Maps • Light Field Rendering and Lumigraphs

  6. Light Field Rendering • M. Levoy • A ray is parameterized by its intersection coordinates (u,v,s,t) • The set of all rays that can be parameterized by two grid planes represents a light field slab

  7. Light Field Rendering

  8. Sampling Requirements • S X T = • 256 x 256 • U X V = • 121000 images

  9. IBR with Controllable Illumination • For a static scene, 3 or more images with “orthogonal” lighting can be used to render all possible lighting conditions

  10. Set of all possible images • Original 6 Photos with different lighting conditions • Three basis images

  11. Set of all possible images • a

  12. IBR and Video Scene with Camera Motion • A video scene with camera motion contains a sequence of images of different viewing positions • Applying IBR or IBM, develop algorithm to do video object segmentation • Object elimination inside a video sequence, like the one in “Rising Sun” - Sean Connery • Any help to video understanding ? • Evolution of Vision ?

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