Eye-contact is a key aspect of non-verbal human communication in everyday tasks [1]. It provides important social and emotional information that can increase the effectiveness of human communication [8]. In a conversation, eye-contact, or the lack thereof, is constantly evaluated by human brains. Conversation partners derive subjective judgment of others' credibility, focus and confidence [4] from it. Seeking another person's eye-contact is a signal for them that focus is put on that person and the main receptive senses are prepared to receive input from the other person. Likewise breaking eye-contact usually indicates distraction, loss of confidence, loss of interest or shifting focus to a different target.

Fish Tank Virtual Reality (FTVR) displays create a compelling 3D spatial effect by rendering to the perspective of the viewer with head-tracking. Combining FTVR with a spherical display enhances the 3D experience with unique properties of the spherical screen such as the enclosing shape, consistent curved surface, and borderless views from all angles around the display. The ability to generate a strong 3D effect on a spherical display with head-tracked rendering is promising for increasing user's performance in 3D tasks. An unanswered question is whether these natural affordances of spherical FTVR displays can improve spatial perception in comparison to traditional flat FTVR displays. To investigate this question, we conducted an experiment to see whether users can perceive the depth and size of virtual objects better on a spherical FTVR display compared to a flat FTVR display on two tasks. Using the spherical display, we found significantly that users had 1cm depth accuracy compared to 6.5cm accuracy using the flat display on a depth-ranking task. Likewise, their performance on a size-matching task was also significantly better with the size error of 2.3mm on the spherical display compared to 3.1mm on the flat display. Furthermore, the perception of size-constancy is stronger on the spherical display than the flat display. This study indicates that the natural affordances provided by the spherical form factor improve depth and size perception in 3D compared to a flat display. We believe that spherical FTVR displays have potential as a 3D virtual environment to provide better task performance for various 3D applications such as 3D designs, scientific visualizations, and virtual surgery.

In this work we describe the design, implementation and initial evaluation of a spherical Fish Tank Virtual Reality (FTVR) display for realistic eye-contact. We identify display shape, size, and depth cues as well as model fidelity as important considerations and challenges for setting up realistic eye-contact and package it into a reproducible framework. Based on the design, we implemented and evaluated the system to assess the effectiveness of the eye-contact. In our initial evaluation participants were able to identify eye-contact with an accuracy of 89.6%. Moreover eye-contact with a virtual character triggered changes in participant's social behavior that are in line with real world eye-contact scenarios. Taken together, these results provide practical guidelines for building displays for realistic eye-contact and can be applied to applications such as teleconferencing and VR treatment in psychology.

A mixed reality experience with a physical display, that situates 3D virtual content within the real world, has the potential to help people work and play with 3D information. However, almost all of such "fish tank virtual reality" (FTVR) systems have been isolated to a single-person experience, making them unsuitable for collaborative tasks. In this paper, we present a display system that allows two people to have unobstructed 3D perspective views into a spherical display while still being able to see and talk to one another. We evaluated the system through qualitative observation at a four-day exhibition and found it was effective for providing a convincing, shared 3D experience.