Date of Award

8-2024

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Human Centered Computing

Committee Chair/Advisor

Andrew Robb

Committee Member

Sabarish V. Babu

Committee Member

Christopher Pagano

Committee Member

Guo Freeman

Abstract

Near-field perception and reaching capabilities are fundamental for most interactions in immersive virtual environments (IVEs). To perform actions in IVEs accurately and efficiently, virtual reality (VR) users need to be able to adapt to changes in their perception. Some of these perceptual differences may be inherent to virtual environments, such as the difference in depth perception between the virtual and non-virtual worlds. Others may be deliberate alterations to the user's action capabilities or to their surroundings to make interactions easier. Both the alterations and the user's ability to adjust to them may change over time as they gain experience in IVEs. Such changes may occur rapidly (within a VR session) or gradually (between VR sessions).

This dissertation investigates how VR users' near-field perception and behaviors related to reaching change over time as they gain experience in IVEs. First, we investigated how well VR users could sense and adjust to fixed offsets of their virtual avatar's hand using online control over several weeks. Second, we studied if VR users could calibrate their reaching to various tool lengths across sessions. Finally, we compared users' reaching behaviors with online control versus calibration using two different end-effector representations over time.

In the first study we found that participants' sensitivity to the fixed offsets did not change over time but that related behaviors, such as head movement and performance, did. The results of this study suggest that VR users can improve their near-field reaching capabilities over time even without calibration to fixed offsets. In the second study we found that calibration can not only improve distance estimations within a VR session, but also that repeated calibration over time can reduce or eliminate errors in perception for IVEs between sessions. For the third study, we found that while a user's end-effector representation can influence their reaching capabilities, feedback from online control or calibration is sufficient to improve reach accuracy and performance over time.

These works highlight the impact of calibration on perception in IVEs and how VR users can more quickly adapt to novel experiences. The longitudinal works presented in this dissertation can help frame future studies in VR investigating changes in users' behavior over time. All interactions in VR require some form of perception, and certain interactions (such as training for machines or medical applications) require very fine motor control. Therefore, it is important for us to understand both how VR users can adapt to alterations and to provide recommendations that can aid them in their adaptation process. Ultimately, the goal is to provide VR users the most seamless experience for near-field interactions with the highest level of performance and accuracy.

Author ORCID Identifier

0000-0002-7525-991X

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