虛擬現實光場技術

注意：本文摘取自上海科技大學虛擬現實中心教授虞晶怡的演講，僅做摘錄。

A Light Field Journey To Virtual Reality

報告人：虞晶怡(上海科技大學)

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The Fish Eye Approach

ProjectingP[x,y,z] to[a,b]

a=x/z
b=y/z
r2=a2+b2
θ=atan(r)

Fisheye distortion:

θd=θ(1+k1θ2+k2θ4+k3θ6+k4θ6)

Unidistort to [x′,y′]

x′=(θd/r)x
y′=(θd/r)y

Final pixel coordinate [u,v]

u=f(x′+ay′)
v=fy′

First 360 Attempt: QuickTime VR

Assumption: All cameras have an identical CoP!
1991 Eric Chen

Image Warping

Probabilistic model for image match verification

Image Quilting/Stitching

Stereo Parallax

Motion Parallax

360 Stereo Panomara

Near Stereo Pairs

Problem Dense Input

JUMP’s solution

Problems: Stereo Inconsistency
Incoherent Stitching

The Origin of Light Field (LF):

5D Plenoptic Function [Adelson ‘92]

Light Field Acquisitions:

Camera Arrays

Light Field Cameras

Days of Future Past

Light Field Rendering[Isakesen ‘00, Ng ‘05]

Problems With Light Field Rendering

Solution: Lumigraph

Question: How to Obtain Geometry?

Capability 1: Refocusing

refocusing via ray blending

Capability 2: Focal Symmetry

Depth-from-Defocus
Occlusion Detection

Capability 3: Dense Angular Sampling

Surface Cameras (SCam) Images

• Scam can be used to separate occluding vs. non occluding regions
• Can also used as a consistency metric

How About Using Multiple LFs

• Multi-View Light Field 3D Scanning

Now What? A Leap of Magic! Light Field HMD

Lenticular LF Displays
Compressive LF Displays: Magic Leap/Hololens

How Does It Work?
Solution: Tensor Decomposition

Coclusion: A Light Field Journey to VR