projection

We introduce a new type of interactive surface technology based on a switchable projection screen which can be made diffuse or clear under electronic control. The screen can be continuously switched between these two states so quickly that the change is imperceptible to the human eye. It is then possible to rear-project what is perceived as a stable image onto the display surface, when the screen is in fact transparent for half the time. The clear periods may be used to project a second, different image through the display onto objects held above the surface. At the same time, a camera mounted behind the screen can see out into the environment. We explore some of the possibilities this type of screen technology affords, allowing surface computing interactions to extend 'beyond the display'. We present a single self-contained system that combines these off-screen interactions with more typical multi-touch and tangible surface interactions. We describe the technical challenges in realizing our system, with the aim of allowing others to experiment with these new forms of interactive surfaces.

A number of projects within the computer graphics, computer vision, and human-computer interaction communities have recognized the value of using projected structured light patterns for the purposes of doing range finding, location dependent data delivery, projector adaptation, or object discovery and tracking. However, most of the work exploring these concepts has relied on visible structured light patterns resulting in a caustic visual experience. In this work, we present the first design and implementation of a high-resolution, scalable, general purpose invisible near-infrared projector that can be manufactured in a practical manner. This approach is compatible with simultaneous visible light projection and integrates well with future Digital Light Processing (DLP) projector designs -- the most common type of projectors today. By unifying both the visible and non-visible pattern projection into a single device, we can greatly simply the implementation and execution of interactive projection systems. Additionally, we can inherently provide location discovery and tracking capabilities that are unattainable using other approaches.

This paper presents a programmable infrared (IR) technique that utilizes invisible, programmable markers to support interaction beyond the surface of a diffused-illumination (DI) multi-touch system. We combine an IR projector and a standard color projector to simultaneously project visible content and invisible markers. Mobile devices outfitted with IR cameras can compute their 3D positions based on the markers perceived. Markers are selectively turned off to support multi-touch and direct on-surface tangible input. The proposed techniques enable a collaborative multi-display multi-touch tabletop system. We also present three interactive tools: i-m-View, i-m-Lamp, and i-m-Flashlight, which consist of a mobile tablet and projectors that users can freely interact with beyond the main display surface. Early user feedback shows that these interactive devices, combined with a large interactive display, allow more intuitive navigation and are reportedly enjoyable to use.

Modern computer displays tend to be in fixed size, rigid, and rectilinear rendering them insensitive to the visual area demands of an application or the desires of the user. Foldable displays offer the ability to reshape and resize the interactive surface at our convenience and even permit us to carry a very large display surface in a small volume. In this paper, we implement four interactive foldable display designs using image projection with low-cost tracking and explore display behaviors using orientation sensitivity.

Tabletop applications cannot display more than a few dozen on-screen objects. The reason is their limited size: tables cannot become larger than arm's length without giving up direct touch. We propose creating direct touch surfaces that are orders of magnitude larger. We approach this challenge by integrating high-resolution multitouch input into a back-projected floor. As the same time, we maintain the purpose and interaction concepts of tabletop computers, namely direct manipulation.

We base our hardware design on frustrated total internal reflection. Its ability to sense per-pixel pressure allows the floor to locate and analyze users' soles. We demonstrate how this allows the floor to recognize foot postures and identify users. These two functions form the basis of our system. They allow the floor to ignore users unless they interact explicitly, identify and track users based on their shoes, enable high-precision interaction, invoke menus, track heads, and allow users to control high-degree of freedom interactions using their feet. While we base our designs on a series of simple user studies, the primary contribution on this paper is in the engineering domain.