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emerging technologies

View-Dependent Stereoscopic Projection Onto Everyday Surfaces



A fully automatic image correction technique that supports view-dependent stereoscopic projections of real-time graphics or ordinary video content onto everyday surfaces. The output appears to be projected onto artificial (white and planar) canvases.

The actual surfaces, however, can be geometrically complex, arbitrarily textured, and colored. This technique will enable upcoming portable projectors and ad-hoc stereoscopic visualizations.

Art and Science


In combination with future projector technologies, this technique could enhance life in four ways:

1. Immersive and semi-immersive displays in science, industry, and education
Immersive or semi-immersive, stereoscopic displays are frequently used in industrial applications (automobiles, etc.), for scientific visualizations, and for simulations or industrial presentations. These displays are normally not portable. They are restricted to designated places. Smart projector techniques allow correct view-dependent stereoscopic projection onto existing surfaces of a normal room. The display can set up quickly, and after the presentation, the room can still be used for other purposes.

2. Museum edutainment and theme-park entertainment
Museums, especially, are very restricted in space and budget. In many cases, artificial canvases cannot be installed because they would simply destroy the ambience of the exhibition space. Low budgets also prevent museums from buying expensive stereo displays such as CAVEs. Smart projector techniques will allow museums (and other exhibit spaces) to use existing surfaces (such as the natural stone walls of a castle) for temporary multimedia presentations. Installation will be simple enough to be handled by inexperienced museum staff, and stereoscopic projections can be offered for a very low cost. This could make museum visits more interesting and could generate more visitors. The same advantages would be available to theme-park installations.

3. Embedded home entertainment
Video projectors will play a major role in future home-entertainment applications, ranging from movies and television to computer games and slideshow presentations. With video projectors, displayed images can be larger than the devices themselves. However, we have to give up living space and ambience to set up artificial canvases that are as large as the desired image. Smart projector techniques enable future video projectors to sense their environment and adapt to it. Such projectors can function without an artificial canvas, so they provide a bit more freedom when we decide how to arrange living spaces. They promote a seamless embedding of display technology into our everyday life.

4. Portable projectors
Future projectors will be small and portable. They will deliver large images for mobile devices such as laptops, cell-phones, and PDAs. They will support wireless communication and will be battery powered. Smart projector techniques allow multimedia presentations and other content to be displayed on arbitrary everyday surfaces, which enables true mobility.

Goals


The overall goal of the project is to make artificial projection canvases unnecessary. Instead, images could be projected onto curtains, furniture, table-tops, or papered walls, etc. In addition, ad-hoc stereoscopic visualization of interactive computer graphics on arbitrary surfaces can be supported. This might make special-purpose display devices, such as CAVEs or special wall-like or table-like projection screens, unnecessary.

Innovations


Ad-hoc projection techniques demonstrate how image correction allows projection of pictures, videos, interactive games, or stereoscopic graphics onto arbitrary everyday surfaces. These techniques perform a per-pixel correction of geometry, color, and focus error in real time via hardware-accelerated pixel shading. The parameters that are required to carry out these corrections are determined automatically. Multiple projector units are applied to enhance brightness, to cancel out shadow regions, and to generate images with minimal blur. The system uses only off-the-shelf components (with a single exception of the attached LCD shutters for active stereo projection), and all of these techniques can be implemented in future projectors. These components can lead to embedded home-entertainment solutions, portable presentation technology, and ad-hoc immersive or semi-immersive projection devices.

Vision


Due to increasing market demand, the cost of future projectors will drop as dramatically as it the cost of personal computers, DVD players, and mobile phones. Thus, they will play a dominant role in future home-entertainment equipment. They will replace today's large-screen technologies (flat-panel LCDs, plasma screens, and back-projection screens.

Projectors are also becoming smaller. Another quantum leap toward wireless and portable systems will be utilization of bright, low-power LEDs as light sources. These portable projectors will enable large-screen visualization for mobile computers, such as cell-phones, PDAs, and laptops.

But one major problem remains: the need for an artificial (white and planar) projection canvas that must be as large as the required image. The solution to this problem is a real-time image-correction method that allows projection onto arbitrary surfaces that exist within the specific environment, such as papered walls, colored window curtains, textured table-tops, natural stone walls, etc. Furthermore, this method allows ad-hoc immersive stereoscopic projections, so it could make special-purpose displays such as CAVEs and other immersive or semi-immersive projection devices unnecessary.

Contact


Oliver Bimber
Bauhaus-Universität Weimar
bimber (at) uni-weimar.de

Contributors


Andreas Emmerling
Anselm Grundhoefer
Thomas Klemmer
Christian Nitschke
Gordon Wetzstein
acm.org siggraph.org