International audience

Extended Reality (XR) offers a fascinating capability to transport individuals through time and space. However, are there ways to keep the users grounded in reality while exploring distant landscapes or unfamiliar places? We propose in this paper a Point of Interest portal-based navigation technique that takes full advantage of the available, often limited, physical space of the user while still facilitating natural walking in a virtual environment. This technique can be beneficial for the exploration of Points of Interest (PoIs), which is a recurrent situation in virtual museum visits. It ensures consistency between the physical workspace while a user moves from one PoI to the next, enabling applicability beyond Virtual Reality (VR) and into Mixed Reality (MR) scenarios. The connection of different PoIs in the virtual space is achieved with portals, which are strategically placed in the physical workspace. In order to evaluate the efficiency of this technique, in terms of time, presence and user subjective preference, we conducted an experiment with 19 participants who visited artefacts in various rooms of a fictitious virtual museum. The results indicated that the PoI-based portal technique delivers performance comparable to the most well-known navigation technique (teleportation), while maintaining a balance between immersion in the virtual environment and awareness of the physical space, and offering better spatial consistency. Therefore, it can be considered a viable solution for cross-reality interaction.

In the present study we conducted a systematic review on user studies for Archaeology in eXtended Reality of the last 10 years. After a screening and selection process, 52 articles were selected for an in-depth analysis. Their classification follows different axes: devices, location dependency, type of users, interaction and collaboration. We also organised the existing user studies according to tasks, evaluation measurements, number of participants, and how the study was conducted (pre-test and/or post-test, formative and summative evaluation, quantitative and qualitative data). We found an intertwined relation between Archaeology and Cultural Heritage, which is reflected in the vast presence of applications for museum exhibitions and tours on archaeological sites. Similarities between systems developed for archaeologists and for general public were also investigated. Our purpose was to find a common ground between different user studies that could help designers of the next systems have a base on which they can build their system. We also highlighted which would be the preferred and most suitable evaluation techniques, when they are needed, with the type of users to address. The results show a heterogeneity of measurable variables and possible choices, but some guidelines could be derived.

In many collaborative virtual reality applications, co-located users often have their relative position in the virtual environment matching the one in the real world. The resulting spatial consistency facilitates the co-manipulation of shared tangible props and enables the users to have direct physical contact with each other. However, these applications usually exclude their individual virtual navigation capability, such as teleportation, as it may break the spatial configuration between the real and virtual world. As a result, the users can only explore the virtual environment of approximately similar size and shape compared to their physical workspace. Moreover, their individual tasks with unlimited virtual navigation capability, which often take part in a continuous workflow of a complex collaborative scenario, have to be removed due to this constraint. This work aims to help overcome these limits by allowing users to recover spatial consistency after individual teleportation in order to re-establish their position in the current context of the collaborative task. We use a virtual representation of the user’s shared physical workspace and develop two different techniques to position it in the virtual environment. The first technique allows one user to fully position the virtual workspace, and the second approach enables concurrent positioning by equally integrating the input from all the users. We compared these two techniques in a controlled experiment in a virtual assembly task. The results show that allowing two users to manipulate the workspace significantly reduced the time they spent negotiating the position of the future workspace. However, the inevitable conflicts in simultaneous co-manipulation were also a little confusing to them.

We propose a novel technique to facilitate the selection of data points, a type of data representation we often work with in immersive analytics. We designed and implemented this technique based on the expansion of data points following Fitt’s law. A user study was conducted in an headset-based augmented reality environment. The results significantly highlight the performance of our technique in helping the user select data points and their subjective appreciation in working with the expendable data points.

Teleportation is a navigation technique widely used in virtual reality applications using head-mounted displays. Basic teleportation usually moves a user’s viewpoint to a new destination of the virtual environment without taking into account the physical space surrounding them. However, considering the user’s real workspace is crucial for preventing them from reaching its limits and thus managing direct access to multiple virtual objects. In this paper, we propose to display a virtual representation of the user’s real workspace before the teleportation, and compare manual and automatic techniques for positioning such a virtual workspace. For manual positioning, the user adjusts the position and orientation of their future virtual workspace. A first controlled experiment compared exocentric and egocentric manipulation techniques with different virtual workspace representations, including or not an avatar at the user’s future destination. Although exocentric and egocentric techniques result in a similar level of performance, representations with an avatar help the user to understand better how they will land after teleportation. For automatic positioning, the user selects their future virtual workspace among relevant options generated at runtime. A second controlled experiment shows that the manual technique selected from the first experiment and the automatic technique are more efficient than the basic teleportation. Besides, the manual technique seems to be more suitable for crowded scenes than the automatic one.

Immersive analytics allows a large amount of data and complex structures to be concurrently investigated. We propose a collaborative analytics system that benefits from new advances in immersive technologies for collaborators working in the early stages of data exploration. We implemented a combination of Star Coordinates and Star Plot visualisation techniques to support the visualisation of multidimensional data and the encoding of datasets using simple and compact visual representations. To support data analytics tasks, we propose tools and interaction techniques for users to build decision trees for visualising and analysing data in a top-down method.

Conventional practices for recording student attendance in a classroom, such as roll-call and sign-in-sheet, are proven to be inefficient in terms of time and staff-workload. In addition, they are also prone to human error and bogus attendance, which introduce inaccuracy in the recorded data. A number of studies have been conducted to improve the way we record class attendance. However, some of the proposed solutions are costly and impractical. Most solutions also fail to address bogus attendance. This paper presents a low cost solution in recording student attendance. Attendance is recorded on class photographs, students' faces are automatically located using a face detection technique, and students then registered their attendance by simply identifying their face on the records. Mobile applications were developed for both students and lecturers as the primary interfaces to interact with the system.

We performed a user study in which we investigated the user experience of HoloBee, a visual analytics system for the exploration of bee drift data. We compared two user interfaces, a head-mounted augmented reality (aR) interface and a desktop interface. We present here a correlation analysis of the user experience ratings that we collected in a questionnaire: intuitive, easy to use, comfortable, natural, and efficient. All criteria are strongly correlated with an interface preference rating. Efficient and comfortable are, respectively, found to be most and least strongly correlated with interface preference. Furthermore, while all rating criteria are highly correlated amongst themselves for the desktop interface, natural and intuitive are only marginally correlated for the AR interface indicating that natural user interfaces are not necessarily intuitive.

This paper proposes an approach to process drop cap images - images of decorated letter that begin chapters of old documents that are preserved in libraries, museums - in the domain of characterization, classification and indexing of old documents. The originality of our proposal is based on the fact that we do not try to extract the letter of drop caps but to classify the drop caps according to period, author and style. The drop caps are characterized by using relevant visual features such as length, thickness, orientation, complexity and change of direction on their primitive elements: strokes. The purpose of this approach is to efficiently extract information embedded in the drop caps for the classification and the indexing of old documents. These new visual features based on bags of strokes are more easily calculable and generally applicable than texture or shape features. Experiments based on characterization, classification and indexing phases demonstrate the performance of our propositions and the advances that they represent in terms of content-based drop caps retrieval.