Topic
Keystone effect
About: Keystone effect is a research topic. Over the lifetime, 59 publications have been published within this topic receiving 764 citations.
Papers published on a yearly basis
Papers
14 Oct 2000
TL;DR: A presentation interface that pre-warps the image to be projected in such a way that the distortions induced by the projector-screen geometry precisely negate the warping, allowing the projector to be placed anywhere in the presentation room.
Abstract: Projection systems have become the ubiquitous infrastructure for presentation technology. However, unless the projector is precisely aligned to the presentation screen, the resulting image suffers from perspective (keystone) distortions requiring manual optical or digital correction. This tedious process must be repeated whenever the projector or screen is moved and is increasingly relevant given the emerging trend towards highly-portable LCD projection systems. This paper presents a presentation interface that pre-warps the image to be projected in such a way that the distortions induced by the projector-screen geometry precisely negate the warping. An uncalibrated, low-resolution digital camera is used to infer the projector-screen geometry and to automatically determine the pre-warping parameters. This vision-based system is augmented with a natural interface that enables the user to interactively refine the suggested rectification. Arbitrary distortions due to projector placement are negated, allowing the projector (and camera) to be placed anywhere in the presentation room -- for instance, at the side rather than the center of the room. Our solution works with existing projector hardware, and could easily be incorporated into the next generation of LCD projector systems.
60 citations
Patent•
1 Apr 2004
TL;DR: In this paper, an image projection apparatus consisting of a projector (106), a frame (108), and a partially transparent screen (110) is described, where the projector projects an image such that light forming the image impinges upon the screen (11) such that a virtual image is created from light reflected from the screen, the virtual image appearing to be located behind the screen.
Abstract: An image projection apparatus (100) comprises a projector (106), a frame (108), and a partially transparent screen (110). The frame (108) retains the screen (110) under tension, such that the screen (110) is inclined at an angle with respect to a plane of emission of light from the projector (106). The screen (110) has a front surface arranged such that light emitted from the projector (106) is reflected therefrom. The projector (106) projects an image such that light forming the image impinges upon the screen (11) such that a virtual image is created from light reflected from the screen (110), the virtual image appearing to be located behind the screen (110).
60 citations
Patent•
22 Jan 2002TL;DR: In this article, a projector is often positioned so that its optical axis is at an imperfect orthogonal angle with respect to a projection screen, which causes a keystone distortion as well as imperfect focus in the projected image.
Abstract: A projector is often positioned so that its optical axis is at an imperfect orthogonal angle with respect to a projection screen. This position causes a keystone distortion as well as imperfect focus in the projected image. To correct these undesirable problems, initially, a lens and/or an image-forming plate is independently repositioned to bring the projected image into focus based upon user input data. The keystone distortion is also corrected by redrawing the image on an image-forming surface based upon additional user input data.
58 citations
Patent•
13 May 2005TL;DR: In this article, the authors describe a three-dimensional image projection system in which each projector of multiple projectors generates a respective composite of an image, and each vertical slice in the composite image represents a particular portion of the image for projection by the projector onto a specific area of multiple areas on a screen.
Abstract: Three dimensional (3D) image projection is described. In one aspect, each projector of multiple projectors generate a respective composite of an image. With respect to any particular projector, the projector's corresponding composite image encapsulates multiple vertical slices of the image. Each vertical slice in the composite image represents a particular portion of the image for projection by the projector onto a specific area of multiple areas on a screen. The size of the specific area is a function of a width of a viewpoint of multiple viewpoints, wherein the viewpoint is linearly positioned with the specific area on the screen and the projector.
57 citations
TL;DR: In this paper, the authors investigate a market entry scenario where a technologically-superior new platform may overcome its installed base disadvantage with the backing of a strong keystone species advantage within the business ecosystem, called keystone effect in this study, over an incumbent in a market that exhibits indirect network effects.
41 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2017 | 1 |
| 2016 | 2 |
| 2015 | 3 |
| 2014 | 3 |
| 2013 | 1 |
| 2012 | 4 |