John S. Underkoffler

Illuminating light: an optical design tool with a luminous-tangible interface

We describe a novel system for rapid prototyping of laserbased optical and holographic layouts. Users of this optical prototyping tool ‐ called the Illuminating Light system ‐ move physical representations of various optical elements about a workspace, while the system tracks these components and projects back onto the workspace surface the simulated propagation of laser light through the evolving layout. This application is built atop the Luminous Room infrastructure, an aggregate of interlinked, computer-controlled projector-camera units called I/O Bulbs. Philosophically, the work embodies the emerging ideas of the Luminous Room and builds on the notions of ‘graspable media’. We briefly introduce the I/O Bulb and Luminous Room concepts and discuss their current implementations. After an overview of the optical domain that the Illuminating Light system is designed to address, we present the overall system design and implementation, including that of an intermediary toolkit called voodoo which provides a general facility for object identification and tracking.

Emancipated pixels: real-world graphics in the luminous room

We describe a conceptual infrastructure – the Luminous Room – for providing graphical display and interaction at each of an interior architectural spaces various surfaces, arguing that pervasive environmental output and input is one natural heir to todays rather more limited notion of spatially-confined, output-only display (the CRT). We discuss the requirements of such real-world graphics, including computational & networking demands; schemes for spatially omnipresent capture and display ; and issues of design and interaction that emerge under these new circumstances. These discussions are both illustrated and motivated by five particular applications that have been built for a real, experimental Luminous Room space, and by details of the current technical approach to its construction (involving a two-way optical transducer called an I/O Bulb that projects and captures pixels).

Electronic display system for computational holography

We present an electro-optical apparatus capable of displaying a computer generated hologram (CGH) in real time. The CGH is calculated by a supercomputer, read from a fast frame buffer, and transmitted to a high-bandwidth acousto-optic modulator (AOM). Coherent light is modulated by the AOM and optically processed to produce a three-dimensional image with horizontal parallax.

Urban Simulation and the Luminous Planning Table: Bridging the Gap between the Digital and the Tangible

Multi-layered manipulative platforms that integrate digital and physical representations will have a significant impact on urban design and planning processes in the future. The usefulness of these platforms will be in their ability to combine and update digital and tangible data in seamless ways to enhance the design process of the professional and the communication process with the public. The Luminous Planning Table is one of the first prototypes that use a tangible computerized interface. The use of this system is unique in the design and presentation process in which, at the moment, the activity of viewing physical models and the viewing of animation and computerized simulations are separate. This ability to engage and provide an integrated medium for information delivery and understanding is promising in its pedagogical, professional, and public engagement outcomes.

Real-time holographic display: improvements using a multichannel acousto-optic modulator and holographic optical elements

Any practical holographic display device relying on the MIT synthetic aperture approach will require time-bandwidth products far exceeding those available with single channel acousto- optic modulators (AOMs). A solution to this problem is to use a multichannel AOM, thus making use of the parallelism inherent in optical systems. It is now technically feasible to accommodate a large number of acoustic channels on a single crystal with a corresponding improvement in image characteristics. The vertical view zone also becomes a significant problem for any large size display since each horizontal scan line is visible only from a narrow angle in the vertical direction. Using holographic optical elements (HOEs) alleviates this limitation in two ways: First, the interline spacing can be adjusted easily with HOEs. Second, it is possible to manufacture an HOE which will act as a one-dimensional diffuser. Placing such an HOE in the vertical focus plane of the display increases the view zone by diffusing each line in the vertical direction, but leaves the horizontal image content unaltered.

A View From the Luminous Room

A new body of research, concerning the divergence of information systems away from todays ubiquitous notion of ‘computer’, is emerging. Though the various threads of inquiry diverge significantly in their approach, each generally seeks some intimate integration of computational resources with its users immediate or extended environment. We introduce here a new project called theLuminous Room, which uses dynamically controlled video projection to permit information access and manipulation throughout an architectural space. A description of the working components of the system is followed by an explication of the philosophies that provide both motivation and a conceptual scaffolding for the work. Finally, we offer speculations about the way in which formal architecture and ‘environmental’ information systems like theLuminous Room might co-develop.

Ultragram: a generalized holographic stereogram

A method for producing holographic stereograms with reduced geometrical constraints is presented. The type of holographic stereogram produced, called the ULTRAGRAM, can offer a combination of large viewing zone, arbitrary viewing distance, minimal image distortion, and high spatial resolution, depending on alterable parameters in the image processing software. Computer-based image processing techniques are used to mimic the effect of optical devices while permitting simple re-configurability. The ULTRAGRAM holographic exposure apparatus can be built with reduced attention to the final viewing geometry. An astigmatic computer graphics camera design greatly simplifies image generation. The techniques described are applicable to both one and multi-step stereograms, optical predistortion methods, and both horizontal and full-parallax systems.

Illuminating light: a casual optics workbench

We describe a novel system for rapid prototyping of laser-based optical and holographic layouts. Users of this experimental direct manipulation tool -- called Illuminating Light -- move physical representations of various optical elements about a workspace; the system tracks these components and projects back onto the workspace surface the simulated propagation of laser light through the evolving layout. This application is built atop the Luminous Room infrastructure, an aggregate of interlinked, computer-controlled projector-camera units called I/0 Bulbs.

Generalized pipeline for preview and rendering of synthetic holograms

We describe a general pipeline for the computation and display of either fully-computed holograms or holographic stereograms using the same 3D database. A rendering previewer on a Silicon Graphics Onyx allows a user to specify viewing geometry, database transformations, and scene lighting. The previewer then generates one of two descriptions of the object--a series of perspective views or a polygonal model--which is then used by a fringe rendering engine to compute fringes specific to hologram type. The images are viewed on the second generation MIT Holographic Video System. This allows a viewer to compare holographic stereograms with fully-computed holograms originating from the same database and comes closer to the goal of a single pipeline being able to display the same data in different formats.