Research Overview

My research interests span computer graphics and human-computer interaction (HCI). Current projects include experimental investigation of virtual and augmented reality environments (the Enhanced Virtual Hand Lab project underway at SFU), interactive systems for collaboration (distance art therapy and hand-held devices for use in classrooms), and data visualization techniques for a variety of applications (forest planning, medical imaging, and Web browsing).

I work on numerical simulation of physics to animate natural phenomena, primarily for special effects in film. I'm more generally interested in the use of numerical methods within graphics for modeling and animation, making more powerful tools for artists. On the flip side, I adapt algorithms for physical simulation in graphics to scientific applications, and work on basic tools in numerical linear algebra and numerical partial differential equations.

My primary research interests lie in computer graphics, and recently also some aspects of computer vision, especially image-based modeling and acquisition. My current research interests focus on interactive rendering using graphics hardware and image-based techniques, as well as image-based measurements, photorealism and global illumination, although I have also worked on some smaller projects in other areas of computer graphics (spline modeling, non-photorealistic rendering).

Computers give us access to and control over data and machines, but they have also taken away the tangible handles our bodies evolved with. My research's larger goal is to restore physicality to computer interaction. In many cases, this means taking it away from the desktop and embedding it in the world at its most natural point of use. I use haptic (touch sense) force feedback as part of a multisensory HCI design toolbox, and apply design techniques to real problems and contexts to better understand physical feedback's ideal role. The applications I've found most exciting to date are those that require continuous and/or expressive control or navigation — e.g. manipulating streaming media, drawing and sculpting, controlling musical instruments, affective displays, and computer-mediated interpersonal affective communication. Other promising areas are those where other senses are overutilized (like driving), or a system is being monitored with low attention (the pager of the future).

My research interests fall within the area of Human-Computer Interaction (HCI). While I am interested in many topics in HCI, my research has focussed on the following sub-areas: Interface design; Adaptive interfaces; Adaptable (customizable) interfaces; Universal Usability; Qualitative and quantitative evaluation methodologies; Computer Supported Cooperative Work; and Computer Supported Collaborative Learning.

I work on information visualization, namely using interactive computer graphics to help people solve problems that require understanding a complex abstract dataset. I'm particularly interested in designing algorithms that scale gracefully to handle the huge datasets that inevitably occur in the real world. I'm also getting interested in how to design visualization systems to best exploit the new generation of high-resolution displays. I'm currently collaborating with researchers in evolutionary biology, data mining, and environmental sustainability.

I am interested in vision — the various ways that humans, animals, and computers use light to see. I believe that vision involves constraints that apply to any system, and that the most successful visual systems are based on very general information-processing strategies. As such, my approach is to examine biological systems (including humans) to see how they operate, and then to look at these mechanisms from a computational point of view to see if they embody more general principles. Among other things, these more general principles can provide a scientific basis for the design of visual interfaces that can interact with human visual systems in an optimal way.

My current research focuses on digital geometry processing and evolves around meshes (polygonal model representations). The main application areas of this research are computer graphics, scientific computing, and computer aided engineering applications. Digital geometry processing utilizes tools from applied computational geometry, geometric modeling, and solid modeling to generate, manipulate, and edit polygonal mesh models.

One of the topics which interest me now is parameterization of mesh surfaces for texture mapping, morphing and other applications in computer graphics and CAGD.

I'm interested in (too) many things, but mainly in computer graphics, physically-based animation and simulation, robotics and control, motion planning, image-based modeling, sketch-based interfaces, and machine learning.

My work in human-centred design theory examines the interaction of human cognitive states and complex sensory environments. These environments may include other inhabitants, requiring an understanding of aspects of communication theory (e.g. Psycholinguistics pragmatics) as well as perceptual cognition (e.g. indexical cognition, functional and apparent space constancy).

By combining the most relevant research in Cognitive and Social Sciences, we are working to create a new basis for the design of interactive computer-mediated environments for emerging product niches and familiar uses. This work has contributed to the creation of two spin-off companies and a number of collaborations with larger industry partners.

I study the function and limits of the human visual system, especially the conscious perception of motion and mental representation of computer-animated figures. My expertise is in designing experimental methodologies for collecting and analysing data from human subject experiments. For my PhD (with Kellogg Booth, Jim Little and Brian Fisher) I studied the relationships between computer representations of computer-animated figures, and people's descriptions of the motions, and their pair-wise comparisons of the motions. For my PostDoc (with Karon Maclean, Ron Rensink and Michiel van de Panne) I'm studying the and their pair-wise comparisons of the motions. For my PostDoc (with Karon Maclean, Ron Rensink and Michiel van de Panne) I'm studying the detection of change in moving figures, the process of developing and deploying haptic icons, and issues surrounding the control of attention and the perception of dynamic events (haptic and visual).

My primary research interests lie in the area of human-computer interaction (HCI). My current research involves the application of different representations of visual space to user interface design, with an emphasis on ubiquitous and collaborative computing environments. I have several other ongoing research projects that look at various facets of HCI: designing multiple input devices for CSCW, comparisons of display characteristics for complex tasks, and physiological measurements for attentive, learning, and affective interfaces.

People often work together to analyze complex information, diagnose problems, and make decisions. Current single-user computer systems and visualization techniques do not adequately support such collaborative work. I develop and evaluate effective visual display and interaction techniques to support collaborative data analysis, with a focus on people working together in the same place at the same time.

I am interested in digital sound in simulation and animation and its integration with graphics and haptics to create multi-modal experiences. I work on the physics underlying sound emission and the creation of physically-based sound synthesis techniques. Thus far I've mainly tackled solids and liquids. I am also interested in the human perception of synthetic sound and how virtual sound interacts with other virtual modalities.

For my Master's thesis, I studied the problem of computing the horizon of a terrain from any distant view point. Using this distance assumption, we only consider the set of horizontal viewing directions. An edge appears on some distant horizon if and only if it supports a horizontal line that is tangent to the edge and does not properly intersect any other part of the terrain.

In my doctorate work, I am interested in information visualization and scientific visualization. More specifically, I am interested in using computers to visualize higher dimensional spaces and the mathematical objects embedded within them.

Today's interfaces are complex, providing access to an increasing number of features. One approach to reducing complexity is to adapt interfaces to the needs of the user, through either system-controlled adaptation adaptive interfaces), or user-controlled adaptation (adaptable interfaces). The long-term goal of this research is to determine how static, adaptive, and adaptable interfaces may affect user groups differently. For example, children may be more efficient with adaptive menus than adults, not requiring as much control over the interface. Possible groups that could be examined include children, the elderly, and cognitively impaired users.

My research interests are in photo-realistic rendering and visualization using real time rendering techniques. I have worked with various kinds of graphics hardware on a variety of projects including volume visualization, realistic rendering of acquired BRDFs as well as rendering algorithms for High Dynamic Range Displays. I'm interested in looking at the entire graphics pipeline as part of my thesis work - from acquisition of scene description such as light and material properties, to realistic rendering of scenes using the acquired data to final processing for display in high dynamic range. I am also interested in integrating image based rendering techniques such as environment maps with traditional rendering algorithms for interactive performance with photo-realism.

The focus of my current and future research involves processing of polygonal meshes in computer graphics. My proposed research builds on my master thesis experience in manipulation of polygonal meshes.

In this research I intend to address the following issues:

1. Feature correspondence of morphed objects.
2. Compatible remeshing of morphed objects.
3. Shape preservation while morphing.

The high-level goal of my master's research has been to explore the process of designing technology that is both usable and adoptable for people with aphasia, an acquired communication disorders that impairs language. As aphasic individuals often have difficulty with reading and writing, simple tasks such as managing one's daily planner can be extremely difficult. Using a participatory design approach, the Enhanced with Sound and Images Planner, or ESI Planner, was developed. It uses triplets of images, sound, and text to redundantly encode appointment data making it easier for people with aphasia to comprehend the information presented.

My research interests include Human-Computer Interaction (HCI) and Computer-Supported Co-Operative Work (CSCW). My current research focuses on co-located collaboration — specifically novel methods of facilitating group interactions on large wall and tabletop displays.

I am researching new methods for generating physically-based motion controllers for articulated characters. Currently, my focus is on walking motions. I am interested in producing controllers for a wide variety of characters and walking styles. I am also exploring ways in which these controllers can adapt to changes in the environment (such as terrain variations) and unexpected changes in the character's state.

My Master's thesis work involves information visualization including research work on TreeJuxtaposer, a phylogenetic tree visualizer, and SequenceJuxtaposer, a genetic sequence visualizer, both of which use techniques to interactively focus in and explore areas of interest while all data is in context.

Although efficiency and usability are important for a successful product or service, relationships between usability and æsthetic aspects are often overlooked in current human-computer interaction research. For example, Don Norman noted that colour computer monitors offer little or no efficiency benefit over black and white monitors; however, most people prefer and use colour monitors. My thesis research explores æsthetic attributes related to physical user-interfaces (such as force-feedback knobs or sliders). For example, what qualities make one physical interface feel more satisfying than another interface?

My research with Michiel van de Panne looks at using principled techniques for finding control strategies for various dynamical systems. Currently we are studying the steering of vehicles such as cars, trucks and bicycles in simulation. Computer animation and robotics are suitable application domains for the techniques being developed.

The spread of complex and pervasive human-machine systems into areas like automobile cockpits and handheld devices has made information overload and constant interruptions a way of life in today's technological society. While it is difficult to quantify the effects of overwhelming and disrupting interfaces, it is generally accepted in the HCI field that the current trend in commercial interface design is to add functions rather than assure usability, in part because the latter is difficult to do when users are doing many things at once. While intelligent systems are becoming commonplace, there remains a fundamental problem of communicating data to the user in a usable way. The goal of my research is to develop and establish the effectiveness of a new approach towards leveraging intelligent systems to create a new class of non-disruptive yet effective user interfaces, by delivering tactile feedback that can be processed non-attentionally.

My MSc. research with Alla Sheffer is about developable surfaces. Our latest project was to segment meshes into developable charts. We have used some of our resulting patterns to create soft-toys and paper copies of popular computer graphics models.

My research focuses on using machine learning techniques to develop controllers for physics-based animation of humanoids.

Haptics — interaction through the sense of touch — shows considerable promise as a user interface modality in mobile and handheld applications, because of its personal, intimate nature, and because of limited bandwidth in the visual and auditory modalities. At the same time, mobile use requires minimization of size, weight, and power consumption, which has presented significant challenges for mobile haptics. We have been working in collaboration with the Haptic Lab at McGill to develop a lightweight, piezoelectrically actuated tactile display and to explore user interface possibilities with haptics in a mobile device.

My thesis work focuses on the empirical evaluation of TreeJuxtaposer and SequenceJuxtaposer, two visualization tools for exploring large amounts of biological data (phylogenetic trees and DNA/RNA sequences, respectively). These tools are based on accordion drawing, a novel, highly scalable variant of the focus + context paradigm common in information visualization. I am interested in determining whether the accordion drawing approach can yield usability benefits in the biological domain as well as comparing it to other types of focus + context visualizations such as overview + detail and fisheye views.

My thesis involves investigating the effects registration and calibration accuracy have on motor performance in immersive virtual reality.

My Master's research involves designing a rendering pipeline for high dynamic range displays, consisting of a normal LCD panel illuminated from behind by a grid of LEDs. The pipeline must take a floating point image, derive the LED and LCD panel values which most accurately represent the original image. The goal is to optimize this normally computationally-expensive operation to run in real-time on consumer graphics hardware while staying within the constraints imposed by human perception.

I'm interested in any physical models that directly apply to computer animation. My thesis work involves creating a system for animating fluids that offers the animator more control of the fluid.

I am now working on a novel user interface, called Animation Palette, for making animation. This system includes both the kinematic (e.g. mocap data) and the dynamic (e.g. physical simulation) motion controls, which can be used to generate many kinds of sports motions, such as platform diving, freestyle aerial skiing, and half-pipe snowboarding.

My research is in the area of computer supported collaborative writing. My specific research goal is to use structured annotations to uniformly support all annotation activities and facilitate workflow management within a co-authoring cycle. Current writing tools support basic annotations, such as edits and comments, which are anchored directly in the document, but these tools are not sophisticated enough to support the full collaborative writing workflow. We propose annotation bundles, which are comprehensive annotation structures that better support the collaborative writing process.