Augmented reality applications allow users to enrich their real surroundings with additional digital content. However, due to the limited field of view of augmented reality devices, it can sometimes be difficult to become aware of newly emerging information inside or outside the field of view. Typical visual conflicts like clutter and occlusion of augmentations occur and can be further aggravated especially in the context of dense information spaces. In this article, we evaluate how multisensory cue combinations can improve the awareness for moving out-of-view objects in narrow field of view augmented reality displays. We distinguish between proximity and transition cues in either visual, auditory or tactile manner. Proximity cues are intended to enhance spatial awareness of approaching out-of-view objects while transition cues inform the user that the object just entered the field of view. In study 1, user preference was determined for 6 different cue combinations via forced-choice decisions. In study 2, the 3 most preferred modes were then evaluated with respect to performance and awareness measures in a divided attention reaction task. Both studies were conducted under varying noise levels. We show that on average the Visual-Tactile combination leads to 63% and Audio-Tactile to 65% faster reactions to incoming out-of-view augmentations than their Visual-Audio counterpart, indicating a high usefulness of tactile transition cues. We further show a detrimental effect of visual and audio noise on performance when feedback included visual proximity cues. Based on these results, we make recommendations to determine which cue combination is appropriate for which application.

Current augmented reality displays still have a very limited field of view compared to the human vision. In order to localize out-of-view objects, researchers have predominantly explored visual guidance approaches to visualize information in the limited (in-view) screen space. Unfortunately, visual conflicts like cluttering or occlusion of information often arise, which can lead to search performance issues and a decreased awareness about the physical environment. In this paper, we compare an innovative non-visual guidance approach based on audio-tactile cues with the state-of-the-art visual guidance technique EyeSee360 for localizing out-of-view objects in augmented reality displays with limited field of view. In our user study, we evaluate both guidance methods in terms of search performance and situation awareness. We show that although audio-tactile guidance is generally slower than the well-performing EyeSee360 in terms of search times, it is on a par regarding the hit rate. Even more so, the audio-tactile method provides a significant improvement in situation awareness compared to the visual approach.

Head-worn devices with a narrow field of view are common commodity for Augmented Reality. However, their limited screen space makes view management difficult. Especially in dense information spaces this potentially leads to visual conflicts such as overlapping labels (occlusion) and visual clutter. In this paper, we look into the potential of using audio and vibrotactile feedback to guide search and information localization. Our results indicate users can be guided with high accuracy using audio-tactile feedback with maximum median deviations of only 2° on longitude, 3.6° on latitude and 0.07 meter in depth. Regarding the encoding of latitude we found a superior performance when using audio, resulting in an improvement of 61% and fastest search times. When interpreting localization cues the maximum median deviation was 9.9° on longitude and 18% of a selected distance to be encoded which could be reduced to 14% when using audio.

Many optical-see-through displays have a relatively narrow field of view. However, a limited field of view can constrain how information can be presented and searched through. To understand these constraints, we present a series of experiments that address the interrelationships between field of view, information density, and search performance. We do so by simulating various fields of view using two approaches: limiting the field of view presented on a Microsoft HoloLens optical-see-through head-worn display and dynamically changing the portion of a large tiled-display wall on which information is presented, for head-tracked users in both cases. Our results indicate a significant effect of information density and field of view on search performance, with potential search performance benefits of using a larger FOV between ca. 7-28%. Furthermore, while grids guided visual search, they did not significantly affect performance.