To determine the accuracy and precision of pupil measurements made with the Tobii 1750 remote video eye tracker, we performed a formal metrological study with respect to a calibrated reference instrument, a medical pupillometer. We found that the eye tracker measures mean binocular pupil diameter with precision 0.10 mm and mean binocular pupil dilations with precision 0.15 mm.

We propose a new way of analyzing pupil measurements made in conjunction with eye tracking: fixation-aligned pupillary response averaging, in which short windows of continuous pupil measurements are selected based on patterns in eye tracking data, temporally aligned, and averaged together. Such short pupil data epochs can be selected based on fixations on a particular spot or a scan path. The windows of pupil data thus selected are aligned by temporal translation and linear warping to place corresponding parts of the gaze patterns at corresponding times and then averaged together. This approach enables the measurement of quick changes in cognitive load during visual tasks, in which task components occur at unpredictable times but are identifiable via gaze data. We illustrate the method through example analyses of visual search and map reading. We conclude with a discussion of the scope and limitations of this new method.

The pupil-measuring capability of video eye trackers can detect the task-evoked pupillary response: subtle changes in pupil size which indicate cognitive load. We performed several experiments to measure cognitive load using a remote video eye tracker, which demonstrate two extensions to current research in this area. First, we show that cognitive pupillometry can be extended from head-mounted to remote eye tracking systems. Second, we demonstrate the feasibility of a more fine-grained approach to analyzing pupil size data gathered with an eye tracker, which provides more detail about the timing and magnitude of changes in cognitive load.

Using gaze information as a form of input poses challenges based on the nature of eye movements and how we humans use our eyes in conjunction with other motor actions. In this paper, we present three techniques for improving the use of gaze as a form of input. We first present a saccade detection and smoothing algorithm that works on real-time streaming gaze information. We then present a study which explores some of the timing issues of using gaze in conjunction with a trigger (key press or other motor action) and propose a solution for resolving these issues. Finally, we present the concept of Focus Points, which makes it easier for users to focus their gaze when using gaze-based interaction techniques. Though these techniques were developed for improving the performance of gaze-based pointing, their use is applicable in general to using gaze as a practical form of input.

Both the Resource Description Framework (RDF), used in the semantic web, and Maya Viz u-forms represent data as a graph of objects connected by labeled edges. Existing systems for flexible visualization of this kind of data require manual specification of the possible visualization roles for each data attribute. When the schema is large and unfamiliar, this requirement inhibits exploratory visualization by requiring a costly up-front data integration step. To eliminate this step, we propose an automatic technique for mapping data attributes to visualization attributes. We formulate this as a schema matching problem, finding appropriate paths in the data model for each required visualization attribute in a visualization template.

Hand-crafted illustrations are often more effective than photographs for conveying the shape and important features of an object, but they require expertise and time to produce. We describe an image compositing system and user interface that allow an artist to quickly and easily create technical illustrations from a set of photographs of an object taken from the same point of view under variable lighting conditions. Our system uses a novel compositing process in which images are combined using spatially-varying light mattes, enabling the final lighting in each area of the composite to be manipulated independently. We describe an interface that provides for the painting of local lighting effects (e.g. shadows, highlights, and tangential lighting to reveal texture) directly onto the composite. We survey some of the techniques used in illustration and lighting design to convey the shape and features of objects and describe how our system can be used to apply these techniques.

We present design principles for creating effective assembly instructions and a system that is based on these principles. The principles are drawn from cognitive psychology research which investigated people's conceptual models of assembly and effective methods to visually communicate assembly information. Our system is inspired by earlier work in robotics on assembly planning and in visualization on automated presentation design. Although other systems have considered presentation and planning independently, we believe it is necessary to address the two problems simultaneously in order to create effective assembly instructions. We describe the algorithmic techniques used to produce assembly instructions given object geometry, orientation, and optional grouping and ordering constraints on the object's parts. Our results demonstrate that it is possible to produce aesthetically pleasing and easy to follow instructions for many everyday objects.