Model-based Real-time Visualization of Realistic Three-Dimensional Heat Maps for Mobile Eye Tracking and Eye Tracking in Virtual Reality

Pfeiffer T, Memili C. Model-based Real-time Visualization of Realistic Three-Dimensional Heat Maps for Mobile Eye Tracking and Eye Tracking in Virtual Reality. In: Proceedings of the Ninth Biennial ACM Symposium on Eye Tracking Research & Applications. New York, NY, USA: ACM Press; 2016: 95-102.Heat maps, or more generally, attention maps or saliency maps are an often used technique to visualize eye-tracking data. With heat maps qualitative information about visual processing can be easily visualized and communicated between experts and laymen. They are thus a versatile tool for many disciplines, in particular for usability engineering, and are often used to get a first overview about recorded eye-tracking data. Today, heat maps are typically generated for 2D stimuli that have been presented on a computer display. In such cases the mapping of overt visual attention on the stimulus is rather straight forward and the process is well understood. However, when turning towards mobile eye tracking and eye tracking in 3D virtual environments, the case is much more complicated. In the first part of the paper, we discuss several challenges that have to be considered in 3D environments, such as changing perspectives, multiple viewers, object occlusions, depth of fixations, or dynamically moving objects. In the second part, we present an approach for the generation of 3D heat maps addressing the above mentioned issues while working in real-time. Our visualizations provide high-quality output for multi-perspective eye-tracking recordings of visual attention in 3D environments

Model-based Real-time Visualization of Realistic Three-Dimensional Heat Maps for Mobile Eye Tracking and Eye Tracking in Virtual Reality

Pfeiffer T, Memili C. Model-based Real-time Visualization of Realistic Three-Dimensional Heat Maps for Mobile Eye Tracking and Eye Tracking in Virtual Reality. In: Proceedings of the Ninth Biennial ACM Symposium on Eye Tracking Research & Applications. New York, NY, USA: ACM Press; 2016: 95-102.Heat maps, or more generally, attention maps or saliency maps are an often used technique to visualize eye-tracking data. With heat maps qualitative information about visual processing can be easily visualized and communicated between experts and laymen. They are thus a versatile tool for many disciplines, in particular for usability engineering, and are often used to get a first overview about recorded eye-tracking data. Today, heat maps are typically generated for 2D stimuli that have been presented on a computer display. In such cases the mapping of overt visual attention on the stimulus is rather straight forward and the process is well understood. However, when turning towards mobile eye tracking and eye tracking in 3D virtual environments, the case is much more complicated. In the first part of the paper, we discuss several challenges that have to be considered in 3D environments, such as changing perspectives, multiple viewers, object occlusions, depth of fixations, or dynamically moving objects. In the second part, we present an approach for the generation of 3D heat maps addressing the above mentioned issues while working in real-time. Our visualizations provide high-quality output for multi-perspective eye-tracking recordings of visual attention in 3D environments

MAP3D: An explorative approach for automatic mapping of real-world eye-tracking data on a virtual 3D model

Mobile eye tracking helps to investigate real-world settings, in which participants can move freely. This enhances the studies’ ecological validity but poses challenges for the analysis. Often, the 3D stimulus is reduced to a 2D image (reference view) and the fixations are manually mapped to this 2D image. This leads to a loss of information about the three-dimensionality of the stimulus. Using several reference images, from different perspectives, poses new problems, in particular concerning the mapping of fixations in the transition areas between two reference views. A newly developed approach (MAP3D) is presented that enables generating a 3D model and automatic mapping of fixations to this virtual 3D model of the stimulus. This avoids problems with the reduction to a 2D reference image and with transitions between images. The x, y and z coordinates of the fixations are available as a point cloud and as .csv output. First exploratory application and evaluation tests are promising: MAP3D offers innovative ways of post-hoc mapping fixation data on 3D stimuli with open-source software and thus provides cost-efficient new avenues for research

Three-dimensional gaze projection heat-mapping of outdoor mobile eye-tracking data

The mobilization of eye-tracking for use outside of the laboratory provides new opportunities for the assessment of pedestrian visual engagement with their surroundings. However, the development of data representation techniques that visualize the dynamics of pedestrian gaze distribution upon the environment they are situated within remains limited. The current study addresses this through highlighting how mobile eye-tracking data, which captures where pedestrian gaze is focused upon buildings along urban street edges, can be mapped as three-dimensional gaze projection heat-maps. This data processing and visualization technique is assessed during the current study along with future opportunities and associated challenges discussed

MAP3D: An explorative approach for automatic mapping of real-world eye-tracking data on a virtual 3D model

Mobile eye tracking helps to investigate real-world settings, in which participants can move freely. This enhances the studies’ ecological validity but poses challenges for the analysis. Often, the 3D stimulus is reduced to a 2D image (reference view) and the fixations are manually mapped to this 2D image. This leads to a loss of information about the three-dimensionality of the stimulus. Using several reference images, from different perspectives, poses new problems, in particular concerning the mapping of fixations in the transition areas between two reference views. A newly developed approach (MAP3D) is presented that enables generating a 3D model and automatic mapping of fixations to this virtual 3D model of the stimulus. This avoids problems with the reduction to a 2D reference image and with transitions between images. The x, y and z coordinates of the fixations are available as a point cloud and as .csv output. First exploratory application and evaluation tests are promising: MAP3D offers innovative ways of post-hoc mapping fixation data on 3D stimuli with open-source software and thus provides cost-efficient new avenues for research

Contributions to virtual reality

153 p.The thesis contributes in three Virtual Reality areas: ¿ Visual perception: a calibration algorithm is proposed to estimate stereo projection parameters in head-mounted displays, so that correct shapes and distances can be perceived, and calibration and control procedures are proposed to obtain desired accommodation stimuli at different virtual distances.¿ Immersive scenarios: the thesis analyzes several use cases demanding varying degrees of immersion and special, innovative visualization solutions are proposed to fulfil their requirements. Contributions focus on machinery simulators, weather radar volumetric visualization and manual arc welding simulation.¿ Ubiquitous visualization: contributions are presented to scenarios where users access interactive 3D applications remotely. The thesis follows the evolution of Web3D standards and technologies to propose original visualization solutions for volume rendering of weather radar data, e-learning on energy efficiency, virtual e-commerce and visual product configurators

Eye-tracking Analysis of Interactive 3D Geovisualization

This paper describes a new tool for eye-tracking data and their analysis with the use of interactive 3D models. This tool helps to analyse interactive 3D models easier than by time-consuming, frame-by-frame investigation of captured screen recordings with superimposed scanpaths. The main function of this tool, called 3DgazeR, is to calculate 3D coordinates (X, Y, Z coordinates of the 3D scene) for individual points of view. These 3D coordinates can be calculated from the values of the position and orientation of a virtual camera and the 2D coordinates of the gaze upon the screen. The functionality of 3DgazeR is introduced in a case study example using Digital Elevation Models as stimuli. The purpose of the case study was to verify the functionality of the tool and discover the most suitable visualization methods for geographic 3D models. Five selected methods are presented in the results section of the paper. Most of the output was created in a Geographic Information System. 3DgazeR works with generic CSV files, SMI eye-tracker, and the low-cost EyeTribe tracker connected with open source application OGAMA. It can compute 3D coordinates from raw data and fixations

Sampling rate influences saccade detection in mobile eye tracking of a reading task

The purpose of this study was to compare saccade detection characteristics in two mobile eye trackers with different sampling rates in a natural task. Gaze data of 11 participants were recorded in one 60 Hz and one 120 Hz mobile eye tracker and compared directly to the saccades detected by a 1000 HZ stationary tracker while a reading task was performed. Saccades and fixations were detected using a velocity based algorithm and their properties analyzed. Results showed that there was no significant difference in the number of detected fixations but mean fixation durations differed between the 60 Hz mobile and the stationary eye tracker. The 120 Hz mobile eye tracker showed a significant increase in the detection rate of saccades and an improved estimation of the mean saccade duration, compared to the 60 Hz eye tracker. To conclude, for the detection and analysis of fast eye movements, such as saccades, it is better to use a 120 Hz mobile eye tracker