Class 6 slides

Interactive Computer Graphics: A Top-Down Approach Using OpenGL (4th Edition)

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1 ECE/CS 433 Introduction to Computer Graphics Pradeep Sen Advanced Graphics Lab Class 6 September 6, 2007 ECE/CS 433 Introduction to Computer Graphics Pradeep Sen Class 6 – September 6, 2007 Last time ± Started talking about light fields ECE/CS 433 Introduction to Computer Graphics Pradeep Sen Class 6 – September 6, 2007 Today ± More on light fields and image formation ECE/CS 433 Introduction to Computer Graphics Pradeep Sen Class 6 – September 6, 2007 The light-field P 1 α 1 β 1 P 2 α 2 β 2 L(x, y, θ , φ ) source: Photography , by London & Upton ECE/CS 433 Introduction to Computer Graphics Pradeep Sen Class 6 – September 6, 2007 Light field definition ± Formally, we define a light field as the radiance at every point in any direction ± Informally, we can think of radiance as the amount of light in a ray ± Formally, radiance is the power per unit projected area perpendicular to the ray per unit solid angle in the direction of the ray (units: W/m 2 sr) ECE/CS 433 Introduction to Computer Graphics Pradeep Sen Class 6 – September 6, 2007 Light field parameterization ± In a static scene with occluders, the light- field is a 5-D function (x, y, z, , ) . ± In free-space (no occluders), this turns into a 4-D function (x, y, , ) source: Photography , by London & Upton
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2 ECE/CS 433 Introduction to Computer Graphics Pradeep Sen Class 6 – September 6, 2007 Not a new idea… source: Leonardo Da Vinci’s notebook (~1500) ECE/CS 433 Introduction to Computer Graphics Pradeep Sen Class 6 – September 6, 2007 More recent work ± “Light-field” term coined by A. Gershun (1936) ± Brought to the attention of computer vision community by Adelson et al. (plenoptic function) (1992) ± Introduced to graphics as an Image-Based Rendering technique by Levoy & Hanrahan, and Gortler et al., independently (1996) ECE/CS 433 Introduction to Computer Graphics Pradeep Sen Class 6 – September 6, 2007 Things to think about… ± Representation ± Acquisition ± Compression ± Display ± Useful applications There are many interesting things about light-fields to think about and investigate: ECE/CS 433 Introduction to Computer Graphics Pradeep Sen Class 6 – September 6, 2007 Light field representation ± Levoy and Hanrahan (1996) adopted a two- plane parameterization u v s t (u 0 , v 0 ) (s 0 , t 0 ) L(s,t,u,v) ECE/CS 433 Introduction to Computer Graphics Pradeep Sen Class 6 – September 6, 2007 Light field representation ± Levoy and Hanrahan (1996) adopted a two- plane parameterization u v s t u v L(s,t,u,v) ECE/CS 433 Introduction to Computer Graphics Pradeep Sen Class 6 – September 6, 2007 Acquiring light-fields ± For static scenes we can use a spherical gantry… Stanford spherical gantry
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3 ECE/CS 433 Introduction to Computer Graphics Pradeep Sen Class 6 – September 6, 2007 Acquiring light-fields source: Photography , by London & Upton Stanford camera array (u, v) ± For dynamic scenes we can use a camera array… (s, t) ECE/CS 433 Introduction to Computer Graphics Pradeep Sen Class 6 – September 6, 2007 Acquiring light-fields ± Unfortunately, the camera array is awkward to transport ± We’ll talk later about hand-held light-field
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This note was uploaded on 01/30/2008 for the course ECE 433 taught by Professor Sen during the Fall '07 term at New Mexico.

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Class 6 slides - Last time ECE/CS 433 Introduction to...

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