Light Field RenderingOverviewPurposePurpose-Cont.What is Light Field4D RepresentationRepresentation of Light FieldCreation of Light FieldCreation of Light FieldsDisplayDiscussionSlide 12CompressionCompression -Cont.Slide 15Acquisition-Option1Signal CameraAcquisition-Option2Camera ArraysAcquisition-Option3Hand-held Plenoptic CameraHand-held Plenoptic Camera- Cont.More on Plenoptic CameraSlide 24Dynamic Reparameterized Light FieldsSlide 26Slide 27Slide 28Slide 29Slide 30Slide 31Variable AperturesAperture FiltersSlide 34Slide 35Application of Light FieldsApplications of Light FieldSlide 38Future of Light FieldThank you!Light Field RenderingShijin KongLijie HengOverview•Purpose•Algorithm 1. representation of light field-4D (u, v, s, t) 2. creation 3. compression 4. display•Discussion•ApplicationsPurpose•To generate a new view from an arbitrary position•Previous methods Environment maps - depth information Interpolating - correspondence pointsPurpose-Cont.•Limit: “fill in the gaps”, incorrect correspondences •To avoid these problems, a new method was proposed in this paper by using light fieldWhat is Light Field•In the real 3D world, how to represent a ray? Using 5D Plenoptic Function4D Representation•In free space (no occluders), oriented lines could be represented in 4DRepresentation of Light FieldCreation of Light Field•Rendered ImagesCreation of Light Fields•Aliasing Low-pass filterDisplayShow videoDiscussion•Advantages 1. easy, robust 2. fast to create new views -sampling•Limitations Large amount of data Building acquisition device Fixed focal surfaceDiscussion•Limitations Large amount of data Building acquisition device Fixed focal surfaceCompression•VQ•Lempel-Zic CodingCompression -Cont.Discussion•Limitations Large amount of data Building acquisition device Fixed focal surfaceAcquisition-Option1•Using a single camera -hard to manipulate -need refocus -aliasing/blurrinessSignal CameraAcquisition-Option2•Using an array of cameras -fixed -inflexibleCamera ArraysAcquisition-Option3•Using an microlens array to replace the camera array -easy to use -reduce aliasingHand-held Plenoptic CameraHand-held Plenoptic Camera- Cont.More on Plenoptic Camera•Higher image resolution, increased sharpness of the refocused photographs. •Shorter exposures and lower image noiseDiscussion•Limitations Large amount of data Building acquisition device Fixed focal surfaceDynamic Reparameterized Light Fields•Focal Surface is fixed when create light fields•What if recover pixels that are not on the focal surface•Reparameterize to required focal surfaceDynamic Reparameterized Light Fields•Move to desired new focal surface•Create a new 4D space with new focal surface•Recove ray with Reparameterization•(u, v, s, t) => (u, v, f, g)FDynamic Reparameterized Light Fields•Recover ray r•Resample from ray (s’, t’, f, g) and (s’’, t’’, f, g)•Interpolation, reconstruction with filter, … , etcDynamic Reparameterized Light FieldsDynamic Reparameterized Light Fields•Change the shape of focal surface •Gives focus on 3D object rather than planesDynamic Reparameterized Light FieldsDynamic Reparameterized Light FieldsVariable Apertures•Also can generate variable aperture•Aperture–Control amount of light–Control depth of fields•Aperture Filter: –Control how many cameras are used to resample a required ray–Larger apertures produce images with narrow range of focusAperture FiltersVariable AperturesVariable AperturesApplication of Light Fields•Multipersepective panorama•Lens simulationApplications of Light Field•Multipersepective panoramaApplications of Light Field•Lens simulation–Simulate lens with large apertureFuture of Light Field–Need better ways to capture larger collection of viewpoints–Reconstruct 3D shape with vision algorithms–More images captured allow peeking arround occlusionsThank
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