When using Head-Mounted Displays (HMDs), users may not always notice or report visual discomfort by blurred vision through unadjusted lenses, motion sickness, and increased eye strain. Current measures for visual discomfort rely on users’ self-reports those susceptible to subjective differences and lack of real-time insights. In this work, we investigate if Electroencephalography (EEG) can objectively measure visual discomfort by sensing Event-Related Potentials (ERPs). In a user study ($\mathrm{N}=20$), we compare four different levels of Gaussian blur in a user study while measuring ERPs at occipito-parietal EEG electrodes. The findings reveal that specific ERP components (i.e., P1, N2, and P3) discriminated discomfort-related visual stimuli and indexed increased load on visual processing and fatigue. We conclude that time-locked brain activity can be used to evaluate visual discomfort and propose EEG-based automatic discomfort detection and prevention tools.

Marine growth on submerged structures causes additional mechanical loads from drag and mass increases. In order to ensure structural integrity, regular inspection and cleaning procedures are carried out on the submerged structures, most commonly using remote-operated vehicles (ROVs). Often, the measurement methodology in these inspections is spot-checks using simple mechanical gauges, which yield a rough estimate of marine growth thickness. Expanding on this method, in order to optimize these inspection and cleaning procedures, modern methods for 3D surface measurement can be applied to increase inspection quality and ensure that superfluous cleaning is not carried out. This work investigates three state-of-the-art sensor technologies: a Time-of-Flight depth camera based on modulated visible blue laser illumination, a commercial stereo-vision solution based on visible-light sensors, and high-frequency imaging sonar. The sensors' performance has been compared in a laboratory environment to assess their suitability for use as a measurement device for marine-growth measurement in terms of accuracy, resolution, and noise/artifacts. It is concluded that the measurement fidelity of all evaluated sensors shows promise for the application, pending future evaluation in a real-world test.

Advances in vehicle automation and the resulting change of the interior of cars lead to new challenges for user interface concepts. Augmented reality (AR) is a promising solution for the emerging design needs due to its diverse opportunities for user interaction and presenting information. This paper supports the development of novel AR applications. We describe a corresponding use case set consisting of 98 examples from a literature review and two focus groups. Based on these samples we present a design space for in-car AR applications. To demonstrate the benefit thereof, we show a fictional design process including our proposed design space to derive a custom AR system. This work supports designers and engineers by providing a systematic approach for integrating 3D AR interfaces in a vehicle, excluding windshields and windows.

Focusing on pedestrian safety in the era of automated vehicles, we investigate the interaction between pedestrians and automated cars. In particular, we investigate the influence of external car displays (ECDs) on pedestrians' crossing behavior, and the time needed to make a crossing decision. We present a study in a high-immersion VR environment comparing three alternative car-situated visualizations: a smiling grille, a traffic light style indicator, and a gesturing robotic driver. Crossing at non-designated crossing points on a straight road and at a junction, where vehicles turn towards the pedestrian, are explored. We report that ECDs significantly reduce pedestrians' decision time, and argue that ECDs support comfort, trust and acceptance in automated vehicles. We believe ECDs might become a valuable addition for future vehicles.

When wearing a head-mounted display (HMD) in everyday environments, interactions with real world bystanders often fail due to the visual barrier. As a result, the HMD user takes off the headset, which ends the virtual reality (VR) experience. We address this problem by providing a shared surface with the same content for both users, which is located at the same physical position in the real and the virtual world. In a between-subject user study (N = 40), we investigate the effects of a shared surface for short-term collaboration in co-located mixed-presence scenarios. We compare (a) real-world collaboration, (b) having a shared surface only and (c) combining the shared surface with an avatar representation of the real world user in VR. We could show that shared surfaces are helpful for mixed-presence collaboration. Adding an avatar in VR improves performance measures such as task-completion time, error rate and number of clarifying questions. To support future work in this field, we finally propose design implications and research directions.