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.

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.

Video projectors have typically been used to display images on surfaces whose geometric relationship to the projector remains constant, such as walls or pre-calibrated surfaces. In this paper, we present a technique for projecting content onto moveable surfaces that adapts to the motion and location of the surface to simulate an active display. This is accomplished using a projector based location tracking techinque. We use light sensors embedded into the moveable surface and project low-perceptibility Gray-coded patterns to first discover the sensor locations, and then incrementally track them at interactive rates. We describe how to reduce the perceptibility of tracking patterns, achieve interactive tracking rates, use motion modeling to improve tracking performance, and respond to sensor occlusions. A group of tracked sensors can define quadrangles for simulating moveable displays while single sensors can be used as control inputs. By unifying the tracking and display technology into a single mechanism, we can substantially reduce the cost and complexity of implementing applications that combine motion tracking and projected imagery.

A person seeking another person's attention is normally able to quickly assess how interruptible the other person currently is. Such assessments allow behavior that we consider natural, socially appropriate, or simply polite. This is in sharp contrast to current computer and communication systems, which are largely unaware of the social situations surrounding their usage and the impact that their actions have on these situations. If systems could model human interruptibility, they could use this information to negotiate interruptions at appropriate times, thus improving human computer interaction.This article presents a series of studies that quantitatively demonstrate that simple sensors can support the construction of models that estimate human interruptibility as well as people do. These models can be constructed without using complex sensors, such as vision-based techniques, and therefore their use in everyday office environments is both practical and affordable. Although currently based on a demographically limited sample, our results indicate a substantial opportunity for future research to validate these results over larger groups of office workers. Our results also motivate the development of systems that use these models to negotiate interruptions at socially appropriate times.

Toolkits and other tools have dramatically reduced the time and technical expertise needed to design and implement graphical user interfaces (GUIs) allowing high-quality, iterative, user-centered design to become a common practice. Unfortunately the generation of functioning prototypes for physical interactive devices as not had similar support -- it still requires substantial time and effort by individuals with highly specialized skills and tools. This creates a divide between a designers' ability to explore form and interactivity of product designs and the ability to iterate on the basis of high fidelity interactive experiences with a functioning prototype. To help overcome this difficulty we have developed the Calder hardware toolkit. Calder is a development environment for rapidly exploring and prototyping functional physical interactive devices. Calder provides a set of reusable small input and output components, and integration into existing interface prototyping environments. These components communicate with a computer using wired and wireless connections. Calder is a tool targeted toward product and interaction designers to aid them in their early design process. In this paper we describe the process of gaining an understanding of the needs and workflow habits of our target users to generate a collection of requirements for such a toolkit. We describe technical challenges imposed by these needs, and the specifics of design and implementation of the toolkit to meet these challenges.

In this paper we present a system for providing tactile feedback for stylus-based touch-screen displays. The Haptic Pen is a simple low-cost device that provides individualized tactile feedback for multiple simultaneous users and can operate on large touch screens as well as ordinary surfaces. A pressure-sensitive stylus is combined with a small solenoid to generate a wide range of tactile sensations. The physical sensations generated by the Haptic pen can be used to enhance our existing interaction with graphical user interfaces as well as to help make modern computing systems more accessible to those with visual or motor impairments.

Projection technology typically places several constraints on the geometric relationship between the projector and the projection surface to obtain an undistorted, properly sized image. In this paper we describe a simple, robust, fast, and low-cost method for automatic projector calibration that eliminates many of these constraints. We embed light sensors in the target surface, project Gray-coded binary patterns to discover the sensor locations, and then prewarp the image to accurately fit the physical features of the projection surface. This technique can be expanded to automatically stitch multiple projectors, calibrate onto non-planar surfaces for object decoration, and provide a method for simple geometry acquisition.

This paper describes how to instrument the physical world so that objects become self-describing, communicating their identity, geometry, and other information such as history or user annotation. The enabling technology is a wireless tag which acts as a radio frequency identity and geometry (RFIG) transponder. We show how addition of a photo-sensor to a wireless tag significantly extends its functionality to allow geometric operations - such as finding the 3D position of a tag, or detecting change in the shape of a tagged object. Tag data is presented to the user by direct projection using a handheld locale-aware mobile projector. We introduce a novel technique that we call interactive projection to allow a user to interact with projected information e.g. to navigate or update the projected information.The ideas are demonstrated using objects with active radio frequency (RF) tags. But the work was motivated by the advent of unpowered passive-RFID, a technology that promises to have significant impact in real-world applications. We discuss how our current prototypes could evolve to passive-RFID in the future.

Kinetic (dynamic) typography has demonstrated the ability to add significant emotive content and appeal to expressive text, allowing some of the qualities normally found in film and the spoken word to be added to static text. Kinetic typography has been widely and successfully used in film title sequences as well as television and computer-based advertising. However, its communicative abilities have not been widely studied, and its potential has rarely been exploited outside these areas. This is partly due to the difficulty in creating kinetic typography with current tools, often requiring hours of work to animate a single sentence.In this paper, we present the Kinedit system, a basic authoring tool that takes initial steps toward remedying this situation and hence promoting exploration of the communicative potential of kinetic typography for personal communication. Kinedit is informed by systematic study and characterization of a corpus of examples, and iterative involvement and validation by designers throughout the development process. We describe the tool and its underlying technology, usage experiences, lessons learned, and next steps.

A person seeking someone else's attention is normally able to quickly assess how interruptible they are. This assessment allows for behavior we perceive as natural, socially appropriate, or simply polite. On the other hand, today's computer systems are almost entirely oblivious to the human world they operate in, and typically have no way to take into account the interruptibility of the user. This paper presents a Wizard of Oz study exploring whether, and how, robust sensor-based predictions of interruptibility might be constructed, which sensors might be most useful to such predictions, and how simple such sensors might be.The study simulates a range of possible sensors through human coding of audio and video recordings. Experience sampling is used to simultaneously collect randomly distributed self-reports of interruptibility. Based on these simulated sensors, we construct statistical models predicting human interruptibility and compare their predictions with the collected self-report data. The results of these models, although covering a demographically limited sample, are very promising, with the overall accuracy of several models reaching about 78%. Additionally, a model tuned to avoiding unwanted interruptions does so for 90% of its predictions, while retaining 75% overall accuracy.

Kinetic typography --- text that uses movement or other temporal change --- has recently emerged as a new form of communication. As we hope to illustrate in this paper, kinetic typography can be seen as bringing some of the expressive power of film --- such as its ability to convey emotion, portray compelling characters, and visually direct attention --- to the strong communicative properties of text. Although kinetic typography offers substantial promise for expressive communications, it has not been widely exploited outside a few limited application areas (most notably in TV advertising). One of the reasons for this has been the lack of tools directly supporting it, and the accompanying difficulty in creating dynamic text. This paper presents a first step in remedying this situation --- an extensible and robust system for animating text in a wide variety of forms. By supporting an appropriate set of carefully factored abstractions, this engine provides a relatively small set of components that can be plugged together to create a wide range of different expressions. It provides new techniques for automating effects used in traditional cartoon animation, and provides specific support for typographic manipulations.