A novel approach to three-dimensional (3-D) gaze tracking using 3-D computer vision techniques is proposed in this paper This method employs multiple cameras and multiple point light sources to estimate the optical axis of user's eye without using any user-dependent parameters Thus, it renders the inconvenient system calibration process which may produce possible calibration errors unnecessary A real-time 3-D gaze tracking system has been developed which can provide 30 gaze measurements per second Moreover, a simple and accurate calibration method is proposed to calibrate the gaze tracking system Before using the system, each user only has to stare at a target point for a few (2-3) seconds so that the constant angle between the 3-D line of sight and the optical axis can be estimated The test results of six subjects showed that the gaze tracking system is very promising achieving an average estimation error of under 1/spl deg/

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A novel approach to 3-D gaze tracking using stereo cameras

Changes in six measures of eye activity were assessed as a function of task workload in a target identification memory task. Eleven participants completed four 2-hr blocks of a mock anti-air-warfare task, in which they were required to examine and remember target classifications (friend/enemy) for subsequent prosecution (fire upon/allow to pass), while targets moved steadily toward two centrally located ship icons. Target density served as the task workload variable; between one and nine targets were simultaneously present on the display. For each participant, moving estimates of blink frequency and duration, fixation frequency and dwell time, saccadic extent, and mean pupil diameter, integrated over periods of 10 to 20 s, demonstrated systematic changes as a function of target density. Nonlinear regression analyses found blink frequency, fixation frequency, and pupil diameter to be the most predictive variables relating eye activity to target density. Participant-specific artificial neural network models, developed through training on two or three sessions and subsequently tested on a different session from the same participant, correlated well with actual target density levels (mean R = 0.66). Results indicate that moving mean estimation and artificial neural network techniques enable information from multiple eye measures to be combined to produce reliable near-real-time indicators of workload in some visuospatial tasks. Potential applications include the monitoring of visual activity of system opetators for indications of visual workload and scanning efficiency.

Eye activity correlates of workload during a visuospatial memory task.

This paper describes a computer vision system based on active IR illumination for real-time gaze tracking for interactive graphic display. Unlike most of the existing gaze tracking techniques, which often require assuming a static head to work well and require a cumbersome calibration process for each person, our gaze tracker can perform robust and accurate gaze estimation without calibration and under rather significant head movement. This is made possible by a new gaze calibration procedure that identifies the mapping from pupil parameters to screen coordinates using generalized regression neural networks (GRNNs). With GRNNs, the mapping does not have to be an analytical function and head movement is explicitly accounted for by the gaze mapping function. Furthermore, the mapping function can generalize to other individuals not used in the training. To further improve the gaze estimation accuracy, we employ a hierarchical classification scheme that deals with the classes that tend to be misclassified. This leads to a 10% improvement in classification error. The angular gaze accuracy is about 5° horizontally and 8° vertically. The effectiveness of our gaze tracker is demonstrated by experiments that involve gaze-contingent interactive graphic display.

Eye and gaze tracking for interactive graphic display

A novel non-intrusive eye gaze estimation using cross-ratio under large head motion

This paper addresses the accuracy problem of an eye gaze tracking system. We first analyze the technical barrier for a gaze tracking system to achieve a desired accuracy, and then propose a subpixel tracking method to break this barrier. We present new algorithms for detecting the inner eye corner and the center of an iris at subpixel accuracy, and we apply these new methods in developing a real-time gaze tracking system. Experimental results indicate that the new methods achieve an average accuracy within 1.4/spl deg/ using normal eye image resolutions.

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Subpixel eye gaze tracking

In this paper, a new kind of human-computer interface allowing three-dimensional (3-D) visualization of multimedia objects and eye controlled interaction is proposed. In order to explore the advantages and limitations of the concept, a prototype system has been set up. The testbed includes a visual operating system for integrating novel forms of interaction with a 3-D graphic user interface, autostereoscopic (free-viewing) 3-D displays with close adaptation to the mechanisms of binocular vision, and solutions for nonintrusive eye-controlled interaction (video-based head and gaze tracking). The paper reviews the system's key components and outlines various applications implemented for user testing. Preliminary results show that most of the users are impressed by a 3-D graphic user interface and the possibility to communicate with a computer by simply looking at the object of interest. On the other hand, the results emphasize the need for a more intelligent interface agent to avoid misinterpretation of the user's eye-controlled input and to reset undesired activities.

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An experimental multimedia system allowing 3-D visualization and eye-controlled interaction without user-worn devices

Abstract Volumetric Video is a novel technology that enables the creation of dynamic 3D models of persons, which can then be integrated in any 3D environment. In contrast to classical character animation, volumetric video is authentic and much more realistic and therefore ideal for the transfer of emotions, facial expressions and gestures, which is highly relevant in the context of preservation of contemporary witnesses and survivors of the Holocaust. Fraunhofer Heinrich-Hertz-Institute (HHI) is working on two projects in this cultural heritage context. In a recent project between UFA and Fraunhofer HHI, a VR documentary about the last German survivor of the Holocaust Ernst Grube has been produced. A second project started in collaboration with the University Munich, faculty of languages and literature and Geschwister-Scholl-institute for political science, creating a concept for a VR experience together with Dr. Eva Umlauf, the youngest Jewish survivor in the concentration camp in Auschwitz. This paper presents key aspects of volumetric video and details about both projects including a discussion about the user perspective in such a VR experience.

S. Renault

Papers

An experimental multimedia system allowing 3-D visualization and eye-controlled interaction without user-worn devices

Preserving Memories of Contemporary Witnesses Using Volumetric Video