Shader lamps
Encyclopedia
Shader lamps is a computer graphic technique used to change the appearance of physical objects. The still or moving objects are illuminated, using one or more video projector
s, by static or animated texture or video stream. The method was invented at University of North Carolina at Chapel Hill by Ramesh Raskar, Greg Welch, Kok-lim Low and Deepak Bandyopadhyay in 1999 http://web.media.mit.edu/~raskar/Shaderlamps/ as a follow on to Spatial Augmented Reality http://en.scientificcommons.org/42668071 also invented at University of North Carolina at Chapel Hill in 1998 by Ramesh Raskar, Greg Welch and Henry Fuchs.
A 3D graphic rendering
software is typically used to compute the deformation caused by the non perpendicular, non-planar or even complex projection surface.
Complex objects (or aggregation of multiple simple objects) create self shadows that must be compensated by using several projectors.
The objects are typically replaced by neutral color ones, the projection giving all its visual properties, thus the name shader lamps.
The technique can be used to create a sense of invisibility
, by rendering transparency. The object is illuminated not by a replacement of its own visual properties, but by the corresponding visual surface placed behind the object as seen from an arbitrary viewing point.
Video projector
A video projector is an image projector that receives a video signal and projects the corresponding image on a projection screen using a lens system. All video projectors use a very bright light to project the image, and most modern ones can correct any curves, blurriness, and other...
s, by static or animated texture or video stream. The method was invented at University of North Carolina at Chapel Hill by Ramesh Raskar, Greg Welch, Kok-lim Low and Deepak Bandyopadhyay in 1999 http://web.media.mit.edu/~raskar/Shaderlamps/ as a follow on to Spatial Augmented Reality http://en.scientificcommons.org/42668071 also invented at University of North Carolina at Chapel Hill in 1998 by Ramesh Raskar, Greg Welch and Henry Fuchs.
A 3D graphic rendering
Rendering (computer graphics)
Rendering is the process of generating an image from a model , by means of computer programs. A scene file contains objects in a strictly defined language or data structure; it would contain geometry, viewpoint, texture, lighting, and shading information as a description of the virtual scene...
software is typically used to compute the deformation caused by the non perpendicular, non-planar or even complex projection surface.
Complex objects (or aggregation of multiple simple objects) create self shadows that must be compensated by using several projectors.
The objects are typically replaced by neutral color ones, the projection giving all its visual properties, thus the name shader lamps.
The technique can be used to create a sense of invisibility
Invisibility
Invisibility is the state of an object that cannot be seen. An object in this state is said to be invisible . The term is usually used as a fantasy/science fiction term, where objects are literally made unseeable by magical or technological means; however, its effects can also be seen in the real...
, by rendering transparency. The object is illuminated not by a replacement of its own visual properties, but by the corresponding visual surface placed behind the object as seen from an arbitrary viewing point.
External links
- Shaderlamps.com
- Mitsubishi Electric Research Laboratories, Shader Lamps, Ramesh Raskar, Greg Welch, Kok-lim Low, Deepak Bandyopadhyay, June 2001 (PDF)
- IEEE Computer Society January/February 2007 (Vol. 27, No. 1) pp. 90-96, The Digital Chameleon Principle: Computing Invisibility by Rendering Transparency Frank Nielsen, Sony Computer Science Laboratories