Study assesses the efficacy of hands-free text selection systems for VR headsets

Virtual reality (VR) and augmented reality (AR) head-mounted displays enable users to experience digital content in more immersive and engaging ways. In order to immerse users as deeply as possible in the content, computer scientists have tried to develop navigation and text selection interfaces that do not require the use of their hands.

Rather than pressing buttons on a manual controller, these interfaces would allow users to select text or execute commands simply by moving their head or blinking their eyes. Despite the promise of these approaches, most head-mounted displays today still rely heavily on handheld controllers or hand and finger gestures.

Researchers from Xi’an Jiaotong-Liverpool University and Birmingham City University recently conducted a study aimed at exploring different approaches to hands-free text selection for VR and AR headsets. Their findings, published in a previously published article on arXiv, highlight the benefits of some of these approaches, particularly those that enable wink interactions.

“My group has been working on improving text input for VR/AR for the past six years,” Hai-Ning Liang, one of the researchers who conducted the study, told TechXplore. “Text input is an important element in the text input and editing ecosystem.”

Liang and his colleagues’ current study builds on some of their previous research, which focused on freehand text-entry techniques for VR. In previous studies, the team found that hands-free technologies could simplify user interaction with VR systems and make text entry more intuitive.

“The main goal of our work is to investigate what kinds of features are suitable for hands-free text selection in VR,” Liang explained. “In this new study, we evaluated the potential of freehand text selection approaches in a controlled laboratory experiment with 24 participants, using an within-subjects experimental design (i.e., in which participants experienced all test conditions).”

In their experiments, Liang and his colleagues asked participants to test different text selection methods while performing a specific task. This task mimicked what users might find in real-world environments when using VR, and was divided into three conditions that varied according to the length of text presented to users (i.e., short: single word; medium: 2–3 lines of text; long: 6-8 lines of text).

Participants were asked to use various freehand text selection methods in a VR reading environment that the team created specifically for the experiment. After completing these tests, participants were asked to provide feedback on their experiences.

“Text selection, like many other interactions in VR, requires a pointing mechanism to identify the objects to select before interacting with them, and then another mechanism to indicate the selection,” Liang said. “In this study, we chose head-based pointing as our pointing mechanism, which means that the cursor follows the user’s head movements.”

Liang and his colleagues decided to specifically evaluate the potential of three different text selection methods, called “dwell”, “eye blink” and “voice”. Dwell requires users to hover the mouse pointer over the area containing the text they want to select for a specified amount of time (e.g. 1 second).

When using Eye Blink to select, users were prompted to intentionally blink their eyes to select specific text. Your system recognizes these intentional blinks because they are usually longer than natural ones (around 400ms instead of 100-200ms).

Finally, the Voice approach required users to produce a sound above 60dB. In their experiments, the researchers asked their participants to make a buzzing sound when they wanted to select a text fragment.

“These selection mechanisms, including their parameters, were chosen based on insights from the literature and a series of pilot tests we conducted,” Liang explained. “The insights gathered in our experiment once again confirmed that freehand approaches could be suitable for text selection in VR. Furthermore, we have shown that wink is a very efficient and useful selection mechanism for hands-free interaction.”

The recent work by Liang and his colleagues underscores the enormous potential of freehand text selection techniques to make VR systems more intuitive and convenient to use. In the future, their findings could inspire other research teams to develop and evaluate blink-based techniques for text selection and other types of interactions.

“Our plan for future research in this area will be to focus on making text selection even more efficient and usable, and integrating it into the ecosystem for text editing and document creation in VR/AR,” Liang added. “We will also develop text selection methods that can be used by a variety of restricted users and explore other approaches, including instantaneous for cursor movements instead of head movements.”

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