Computer Graphics (Fall 2003)

COMS 4160, Lecture 1: Overview and History

Ravi Ramamoorthihttp://www.cs.columbia.edu/~cs4160

What is Computer Graphics?

• Anything to do with visual representations on a computer, including– Text (Yes !! An early computer graphics problem)

– WIMP GUIs

– Computer Images (CG = Computer + Pictures)

– 3D Graphics: CG special effects, games, animations

– Scientific Visualization (CFD images)

– Algorithms, theory (physics, math, computation)

– Display devices, hardware (graphics cards, monitors)

The term Computer Graphics was coined by William Fetter of Boeing in 1960

First graphic system in mid 1950s USAF SAGE radar data (developed MIT)

How far we’ve come: TEXT

Manchester Mark I

Display

From Text to GUIs

• Invented at PARC circa 1975. Used in the Apple Macintosh, and now prevalent everywhere.

Xerox Star Windows 1.0

And graphical applications

• Presentations (bar charts, graphs, powerpoint)

• Scientific Visualization

(such as in CFD)

Compressible flow aroundSpace shuttlescience.gmu.edu

Display hardware

• vector displays (1963: modified oscilloscope, 1974: Evans and Sutherland Picture System)

• raster displays– 1975 – Evans and Sutherland frame buffer– 1980s – cheap frame buffers bit-mapped personal

computers– 1990s – liquid-crystal displays laptops– 2000s – micro-mirror projectors digital cinema

• other (stereo, head-mounted displays, autostereoscopic displays, tactile, haptic, sound)

Slide courtesy Marc Levoy

Displaying Images in Color

• 3 phosphors: Red, Green, Blue. 8 bits/channel, color will be 24 bits, approx 17 million colors– Secondary colors: R+B = Magenta

– R+G = Yellow

– B+G = Cyan

– R+G+B = White (PP won’t let me draw 3C diag.)

– Grayscale = .3R + .6G + .1B

• Can also use 8 bits lookup table (256 colors)– Which 256 colors? Color Quantization (eg GIF)

Drawing: Sketchpad (1963)

• Pop up menus• Constraint-based drawing• Hierarchical Modeling

Ivan Sutherland, MIT

• First Interactive Graphics PhD thesis

• 1988 Turing Award “For his pioneering andvisionary contributionsto computer graphics,starting with Sketchpad”

Paint Systems

• SuperPaint system: Richard Shoup, Alvy Ray Smith (PARC, 1973-79)

• Nowadays, Photoshop can draw, paint, edit• Awards to Shoup and Smith: SIGGRAPH 1990 Computer Graphics

Achievement Award, Academy Award (S&E) [with Tom Porter]

Image Processing

• Digitally alter images

• Crop,scale,composite

• Add or remove objects

• Tools are still primitive– Relight, change materials– Combine synthetic objects– Topic of Research

3D Graphics

• Maybe what we generally consider CG

• Currently important in– Design (CAD)– Education, Simulators, VR– Games– Entertainment (Movies), Art

Rendering: 1960s (visibility)

1960s - the visibility problem– Roberts (1963), Appel (1967) - hidden-line algorithms

– Warnock (1969), Watkins (1970) - hidden-surface

– Sutherland (1974) - visibility = sorting

Images from FvDFH, Pixar’s ShutterbugSlide ideas for history of Rendering courtesy Marc Levoy

Rendering: 1970s (raster graphics)

1970s - raster graphics

– Gouraud (1971) - diffuse lighting

– Phong (1974) - specular lighting

– Blinn (1974) - curved surfaces, texture

– Catmull (1974) - Z-buffer hidden-surface algorithm

– Crow (1977) - anti-aliasing

Rendering (1980s, 90s: Global Illumination)

early 1980s - global illumination – Whitted (1980) - ray tracing– Goral, Torrance et al. (1984) radiosity– Kajiya (1986) - the rendering equation

New trends: non-photorealistic rendering

– Drebin et al. (1988), Levoy (1988) - volume rendering

– Haeberli (1990) - impressionistic paint programs

– Salesin et al. (1994-) - automatic pen-and-ink illustration

– Meier (1996) - painterly rendering

New trends: Image-Based Rendering

– Chen and Williams (1993) - view interpolation

– McMillan and Bishop (1995) - plenoptic modeling

– Levoy and Hanrahan (1996) - light field rendering

3D Graphics Pipeline

• Nowadays, increasing reliance on real data (range, photographs, motion capture). Many research questions.

• Also, Image-based rendering: interpolation of photographs

Modeling

Geometry,Lighting,Materials)

Rendering

Shading,Simulationof Light

Animation

Kinematics,Dynamics

Images/Movies

Videos

Relationship to other courses

• Addition of several graphics courses (next year)

• Other related (but not prerequisite) topics of interest: Computer vision, user interfaces, pixel processing.

Administrivia of Course• Website: • Assignments posted on website• TA: • Office Hours• Books• Collaboration Policy• Grading• Difficulty/Time required• Programming• Background (programming, mathematical)• Questions?

Course Outline

• Week 2-3: Transformations and Viewing (Midtm)• Week 3-5: OpenGL (Ass 1,3,4)• Week 6,7: Curves (Ass 2, Midtm)• Week 9-12: Rendering (Final)

Note– First part modeling, next part rendering.

– Assignments above relate to content. Dates on web page. Midterm in class, Final assignment take home

– Remember to send e-mail per assignment 0