Computer graphics

From Wikipedia, the free encyclopedia

This article is about the scientific discipline of computer graphics. For a more general information on computer graphics and applications, see 2D computer graphics and 3D computer graphics.
For the journal by ACM SIGGRAPH, see Computer Graphics (Publication).


Computer graphics is a sub-field of computer science and is concerned with digitally synthesizing and manipulating visual content. Although the term often refers to three-dimensional computer graphics, it also encompasses two-dimensional graphics and image processing. Computer graphics is often differentiated from the field of visualization, although the two have many similarities.

A broad classification of major subfields in computer graphics might be:

  1. Geometry: studies ways to represent and process surfaces
  2. Animation: studies with ways to represent and manipulate motion
  3. Rendering: studies algorithms to reproduce light transport
  4. Imaging: studies image acquisition or image editing
The Utah teapot
The Utah teapot

Contents

[edit] Definition

Computer graphics broadly studies the manipulation of visual and geometric information using computational techniques. Computer graphics as an academic discipline focuses on the mathematical and computational foundations of image generation and processing rather than purely aesthetic issues.

[edit] Geometry

The subfield of geometry studies the representation of three-dimensional objects in a discrete digital setting. Because the appearance of an object depends largely on the exterior of the object, boundary representations are most common in computer graphics. Two dimensional surfaces are a good analogy for the objects most often used in graphics, though quite often these objects are non-manifold. Since surfaces are not finite, a discrete digital approximation is required: polygonal meshes (and to a lesser extent subdivision surfaces) are by far the most common representation, although point-based representations have been gaining some popularity in recent years (see the Symposium on Point-Based Graphics, for instance). These representations are Lagrangian, meaning the spatial locations of the samples are independent. In recent years, however, Eulerian surface descriptions (i.e., where spatial samples are fixed) such as level sets have been developed into a useful representation for deforming surfaces which undergo many topological changes (with fluids being the most notable example[1]).

[edit] Subfields

  • Constructive solid geometry - Process by which complicated objects are modelled with implicit geometric objects and boolean operations
  • Discrete differential geometry - a nascent field which defines geometric quantities for the discrete surfaces used in computer graphics.[2]
  • Digital geometry processing - surface reconstruction, simplification, fairing, mesh repair, parameterization, remeshing, mesh generation, surface compression, and surface editing all fall under this heading.[3][4][5]
  • Point-based graphics - a recent field which focuses on points as the fundamental representation of surfaces.
  • Subdivision surfaces
  • Out-of-core mesh processing - another recent field which focuses on mesh datasets that do not fit in main memory.

[edit] Animation

The subfield of animation studies descriptions for surfaces (and other phenomena) that move or deform over time. Historically most interest in this area has been focused on parametric and data-driven models, but in recent years physical simulation has experienced a renaissance due to the growing computational capacity of modern machines.

[edit] Subfields

[edit] Rendering

Rendering converts a model into an image either by simulating light transport to get physically-based photorealistic images, or by applying some kind of style as in non-photorealistic rendering. The two basic operations in realistic rendering are transport (how much light gets from one place to another) and scattering (how surfaces interact with light). See Rendering (computer graphics) for more information.

[edit] Transport

Transport describes how illumination in a scene gets from one place to another. Visibility is a major component of light transport.

[edit] Scattering

Models of scattering and shading are used to describe the appearance of a surface. Although these issues may seem like problems all on their own, they are studied almost exclusively within the context of rendering.[citation needed] Shading can be broken down into two orthogonal issues, which are often studied independently:

  1. scattering - how light interacts with the surface at a given point
  2. shading - how material properties vary across the surface

The former problem refers to scattering, i.e., the relationship between incoming and outgoing illumination at a given point. Descriptions of scattering are usually given in terms of a bidirectional scattering distribution function or BSDF. The latter issue addresses how different types of scattering are distributed across the surface (i.e., which scattering function applies where). Descriptions of this kind are typically expressed with a program called a shader. (Note that there is some confusion since the word "shader" is sometimes used for programs that describe local geometric variation.)

[edit] Other subfields

  • physically-based rendering - concerned with generating images according to the laws of geometric optics
  • real time rendering - focuses on rendering for interactive applications, typically using specialized hardware like GPUs
  • non-photorealistic rendering
  • relighting - recent area concerned with quickly re-rendering scenes

[edit] History

One of the first displays of computer animation was Futureworld (1976), which included an animation of a human face and hand — produced by Ed Catmull and Fred Parke at the University of Utah.

There are several international conferences and journals where the most significant results in computer graphics are published. Among them are the SIGGRAPH and Eurographics conferences and the Association for Computing Machinery (ACM) Transactions on Graphics journal. The joint Eurographics and ACM SIGGRAPH symposium series features the major venues for the more specialized sub-fields: Symposium on Geometry Processing,Symposium on Rendering, and Symposium on Computer Animation. As in the rest of computer science, conference publications in computer graphics are generally more significant than journal publications (and subsequently have lower acceptance rates)[6][7][8].

An extensive history of computer graphics can be found at this page.

[edit] Applications

[edit] Connected studies

[edit] Computer graphics research groups

[edit] Research

The number of computer science institutions working in computer graphics research has grown rapidly over the past two decades.

Click show for a partial list of research institutions notably involved in graphics research 

[edit] Industry

Industrial labs doing "blue sky" graphics research include:

Major film studios notable for graphics research include:

[edit] Notable researchers in computer graphics

Click show to see the list 

[edit] See also

Numerous sub-areas of computer graphics can be found in Category:3D computer graphics.

[edit] References

Click show to see the list 

[edit] External links

Look up computer graphics in Wiktionary, the free dictionary.