Range Profile SynthesisRange Profile Synthesis

SAMPL Group MeetingSAMPL Group Meeting

10 October 200010 October 2000

By Gerald DalleyBy Gerald Dalley

OverviewOverview

Project GoalProject Goal Ray TracingRay Tracing Range Profiles and Range ImagesRange Profiles and Range Images Lighting ModelsLighting Models POV-RangePOV-Range

Project GoalProject Goal

““Tanks Under Trees”Tanks Under Trees”

Ray Tracing -- 2DRay Tracing -- 2D

Ray Tracing -- Math in 2DRay Tracing -- Math in 2D

Screen

Object Intersected

d s

do

xo

xs

ss

oo x

d

dx s

s

oo x

d

dx

Ray Tracing -- 3DRay Tracing -- 3D

Range Profiles -- Range Profiles -- TheoryTheory

Range Profiles -- Range Profiles -- Current Current ImplementationImplementation

Range ImagesRange Images

Intensity

Range

Typical Lighting ModelTypical Lighting Model

AmbientAmbient• Background light levelBackground light level

DiffuseDiffuse• Matte surfaceMatte surface

SpecularSpecular• The window on the appleThe window on the apple

Bidirectional Radiance Bidirectional Radiance Distribution Functions (BRDFs)Distribution Functions (BRDFs)

Plane of reflection

Plane of IncidenceSurface Normal

r

i

i

r

Figure adapted from Advanced Animation and Rendering Techniques, pg. 34

BRDFs Cont.BRDFs Cont.

Physics-based lightingPhysics-based lighting• Polarized lightPolarized light

Example: Wet pavementExample: Wet pavement

i r

i and r both small

BRDF SimplificationsBRDF Simplifications

Intensity independent of: i (no polarization on incoming light)

r (no polarization on outgoing light)

i=r (light source and camera at same point)

I(i, r, i, r) I()

POV-RangePOV-Range

What is it?What is it? What platforms?What platforms? Performance?Performance?

• 800x600: 800x600: 20 min. /20 min. /

72 frames 72 frames• 8192x8192: 8192x8192:

6.5 hrs. / 6.5 hrs. / 1 frame1 frame

DemoDemo

““POV-Range”POV-Range”

View range image in MatlabView range image in Matlab

Further Information…Further Information…

Foley, Van Dam, Feiner, Hughes. Foley, Van Dam, Feiner, Hughes. Computer Computer Graphics: Principles and PracticeGraphics: Principles and Practice

Watt, Watt. Watt, Watt. Advanced Animation and Advanced Animation and Rendering TechniquesRendering Techniques

www.povray.orgwww.povray.org comp.graphics.rendering.comp.graphics.rendering.raytracingraytracing