Computer Graphics as Virtual Photography -- A Tour June 10, 1999 - - PowerPoint PPT Presentation

Computer Graphics as Virtual Photography -- A Tour

June 10, 1999

June 10, 1999

Motivational Film

✔Geri’s Game

June 10, 1999

More thoughts on projects

✔Implementation as a means to learn a

system or language (VRML, Java3D, Renderman, RADIANCE).

✔Animation -- focus on lighting, scenery,

texture, rather than motion.

✔Implement algorithm presented in

paper.

June 10, 1999

Example projects

✔See Prof Nan Schaller’s page:

– http://www.cs.rit.edu/~ncs/Courses/571.shtml

✔Finding References

– http://liinwww.ira.uka.de/bibliography/Graphics/

June 10, 1999

Just an aside...

✔ Dwarfs that got left on the cutting room floor:

– Clumsy – Dummy – Sleezy – Ozzy – Cheesy – Moe, Curly – Token Joe

June 10, 1999

What is this course about?

✔In short: Creating images by mimicing

photography.

June 10, 1999

What is this course about?

pho•tog•ra•phy, n., the process or art of producing images of objects by the action of light on a sensitized surface, esp, a film in a camera.

Photography = writing with light

June 10, 1999

Process of Creating Images

scene Viewing window light

Direct light Reflected light

Images are a view of the world from a given perspective

June 10, 1999

Computer Graphics as Virtual Photography

camera (captures light) synthetic image camera model (focuses simulated lighting)

processing

photo processing tone reproduction real scene 3D models Photography: Computer Graphics: Photographic print

June 10, 1999

In this lecture

✔Give an overview of the major topics of

the course

– Light – Modeling – Rendering – Camera Models – Tone Reproduction

✔Introduction to papers on reserve

June 10, 1999

Topic I - Light

✔Photography, CG, and sight all have to

do with simulating the response to light!

✔Physically based approach to light and

simulation

June 10, 1999

Topic I : Light

✔Nature of light (June 14th)

– What it is? – How does it behave? – How is it measured? – How does it create color?

✔Lighting Models (June 17th)

– stage lighting – light scattering

June 10, 1999

Topic I: Papers on light

✔ Ashdown -- overview of lighting units. ✔ Glassner -- deriving a spectrum from RGB

values

✔ Marschner -- reversing the pipeline ✔ Greenberg -- image synthesis framework at

Cornell.

✔ Dorsey -- modeling stage lighting ✔ Klassen -- modeling atmospheric effects ✔ Barzel - movie lighting (Toy Story)

June 10, 1999

Computer Graphics as Virtual Photography

camera (captures light) synthetic image camera model (focuses simulated lighting)

processing

photo processing tone reproduction real scene 3D models Photography: Computer Graphics: Photographic print

June 10, 1999

Topic II - Modeling

✔Describing a scene to a computer ✔Shading

– specifying how objects interact with light

✔Solid Modeling

– Object - describing individual objects – Scene - describing placement of objects, lights, and other elements in the entire scene

June 10, 1999

Topic II : Modeling

✔Shading (June 22nd)

– Surface properties – Bidirectional reflection functions (BDRF)

✔Shading Models (June 24th)

– approximating BRDFs

✔Shading Languages

– Renderman

June 10, 1999

Topic II - Modeling

✔Object Modeling (June 29th)

– shape – texture – procedural models

✔Scene Modeling (July 1st)

– coordinate spaces & transformation – graph representation - VRML & Java 3D

June 10, 1999

Topic II: Modeling

✔Special topics

– Particle Systems / Modeling Lightning (July 15th) – VRML ( July 13th)

June 10, 1999

Topic II: Papers on Modeling

✔Shading

– Cook/Torrance - Introduction of BRDFs – Blinn - simulating wrinkled surfaces – Dorsey - modeling surface wear and tear. – Cook - basis for Renderman shading langauge – Hanrahan -- Renderman shading lang. – Perlin -- procedural textures

June 10, 1999

Topic II : Papers on Modeling

✔Object Modeling

– Perlin - procedural 3d models – Musgrave -- fractal landscapes – Fournier -- stochastic models

✔Scene Modeling

– Kilgard -- OpenGL – Strauss -- Inventor (precursor to VRML) – Koved -- Object oriented scene description

June 10, 1999

Computer Graphics as Virtual Photography

camera (captures light) synthetic image camera model (focuses simulated lighting)

processing

photo processing tone reproduction real scene 3D models Photography: Computer Graphics: Photographic print

June 10, 1999

Topic III - Rendering

✔Simulation of the transport of light within

a scene.

– Rendering Equation – Ray tracing – Radiosity – Combined methods – Other methods

June 10, 1999

Topic III: Rendering

✔Rendering Equation (July 6th)

– Theoretical basis for all rendering methods. – Dense but VERY important

June 10, 1999

Topic III: Rendering

✔Ray Tracing (July 8th)

– Following the recursive path of light as it goes from the scene to your eye – Distributed ray tracing

June 10, 1999

Topic III: Rendering

✔Radiosity (July 20th)

– calculation of steady state energy transport.

June 10, 1999

Topic III: Rendering

✔Mixed Methods (July 22)

– Ray tracing + radiosity

✔Alternate methods

– REYES – RADIANCE

June 10, 1999

Topic III: Papers on Rendering

✔Rendering Equation

– Kajia - classic paper

✔Ray Tracing

– Whitted -- original ray tracing paper – Cook -- distributed ray tracing – Musgrave -- ray tracing mirages – Parker -- interactive ray tracing – Heckbert -- ray tracing JELLO (*)

June 10, 1999

Topic III: Papers on Rendering

✔Radiosity

– Goral -- original radiosity paper – Cohen -- 1st radiosity solution – Wallace -- radiosity + ray tracing

✔Other methods

– Cook -- REYES – Ward -- RADIANCE – Gritz -- BMRT

June 10, 1999

Computer Graphics as Virtual Photography

camera (captures light) synthetic image camera model (focuses simulated lighting)

processing

photo processing tone reproduction real scene 3D models Photography: Computer Graphics: Photographic print

June 10, 1999

Topic IV - Camera

✔Focus the light from a scene on to a 2D

plane.

– Perspective transformation – Depth of field – Motion blur – optical simulation – light fields (Lumigraph)

June 10, 1999

Topic IV : Camera Models

✔Models from basic to sophisticated (July

27th)

– Basic Pinhole Camera – Add depth of field and focus – Lens optics simulation

✔Light field rendering (July 29th)

– Rendering using a 4D light space

June 10, 1999

Topic IV: Camera Papers

✔Camera Models

– Potmesil -- first realistic camera model – Kolb -- simulating lens optics – Heidrich -- using light fields

✔Light field rendering

– Gortler -- one of the original papers – Levoy -- the other original paper – Sloan -- fast calculations

June 10, 1999

Computer Graphics as Virtual Photography

camera (captures light) synthetic image camera model (focuses simulated lighting)

processing

photo processing tone reproduction real scene 3D models Photography: Computer Graphics: Photographic print

June 10, 1999

Topic V - Tone Reproduction

✔Response of light used in creating the

final image. (Aug 3)

– Human visual response – Photographic response

✔Issues about output media (Aug 5)

– Color management

June 10, 1999

Topic V: Papers on Tone Reproduction

✔Tone Reproduction

– Tublin -- why it is a problem – Ferwerda -- human visual response – Geigel -- photographic response

✔Color Management

– Glassner -- Device directed rendering – Stone -- gamut mapping – Lindbloom -- accurate color reproduction

June 10, 1999

Intermission

✔Aug 10 - 12 SIGGRAPH

– Looking for guest speakers – Extend classes during last week for more demos?

June 10, 1999

Project Demos

✔Aug 17th and Aug 20th

June 10, 1999

That’s the course in a nutshell

✔Any questions?

June 10, 1999

For next time

✔Keep thinking about your

project…Proposals are due next Thursday

✔Research paper reading begins with

next lecture.

June 10, 1999

Next Class

✔Light

– What it is – How it behaves – How we measure it – Light and color

June 10, 1999

Remember

✔Class Web Site:

– http://www.cs.rit.edu/~jmg/virtualPhoto