Augmented Reality (AR) environments are physical environments with virtual objects superimposed through AR-enabled devices. These virtual objects can range from simple aesthetic objects like pictures to superimposed contextual information about physical items. In most modern AR applications, the augmented spaces exist only for the user who created the environment or for proprietary applications that enable multi-user collaboration in the same environment. However, there is a lack of solutions that enable interoperable collaboration in these personal AR spaces, allowing users to share and contribute to an AR space. We propose a solution that enables users to create their personal AR space that can then be discovered by other users who are in physical proximity to this space, enabling them to view or contribute to the augmented space. In addition, we discuss a solution that utilises the same technique to create AR spaces that are bound to a specific room and can be discovered by users who are in close vicinity to these rooms.
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In Augmented reality (AR), virtual objects are superimposed onto the physical world. Since
its early days, AR has significantly advanced to portable devices such as smartphones and
head-mounted displays [
Superimposed virtual objects or information can be anchored to physical objects and walls
within these physical environments [
A conceptual content-sharing solution for AR, ofering a peer-to-peer and client-server
collaboration solution using events that indicate changes to the virtual objects, was proposed
by Ruth et al. [
© 2024 Copyright for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).
In the i-VISION project [
We propose an interoperable solution that enables users to create their personal AR
environments that can be discovered in the physical world by other users using AR-enabled
devices. Unlike other existing work such as XSpace [
Our proposed solution aims to allow multiple AR devices to contribute to a single shared AR
environment or virtual space belonging to a user. We assume that the AR device used to contribute
to augmented environments is a smart device with access to the Web and can broadcast an
RF signal. In the general architecture of our proposed solution, we let AR devices broadcast a
semantic Bluetooth Low Energy (BLE) beacon advertisement containing the URI of a specific
resource. We utilise the advertising protocol of SemBeacon [
On the left-hand side of the architecture shown in Figure 1, we have a Solid Pod for user 1. The Pod contains all environments owned or modified by the user. An AR device connects to the user’s Solid Pod through a Solid application that authenticates the user, allowing it to modify the resources when editing a virtual environment. In order to enable the discovery of these virtual spaces, the AR device broadcasts the *.ttl file of the environment it is currently in via BLE advertisements. This resource contains all the information about the environment, such as its location, any identifiable features and all virtual objects placed relative to this environment.
Pod User #1 environments/ home/
... office/ data.ttl.acl data.ttl inbox/ .acl Read, Append 1-create.ttl 2-create.ttl 3-move.ttl While the broadcasted URI is public, the access to read this URI is controllable through access control lists implemented in Solid. SemBeacon ofers a broadcasted flag to indicate whether a URI is publicly accessible to prevent applications that do not have access to the resource from attempting to access it.
When another user (e.g. user 2) wants to modify the environment of user 1, they create a
new resource including the modifications and additions to virtual objects or detectable features
(e.g. markers). The application will then notify user 1 about these changes by referencing
the user1-office/data.ttl file in the inbox [
fidmark:markerIdentifier 12 . :printer_info a sosa:FeatureOfInterest ; poso:hasPosition [ poso:isRelativeTo :printer_marker ; ... ] ; omg:hasGeometry [ ... ] .
An alternative architecture is illustrated in Figure 2. In this scenario, a fixed Bluetooth beacon is placed in a room, broadcasting the URI of a single environment. This scenario can be used for public physical environments, such as a meeting room or laboratory, enabling collaboration in AR. Similar to personal environments shown in Figure 1, users store their changes to an environment in their Solid Pod and reference these changes in the inbox of the environment. 2.1. Usage Our solution is depicted in Figure 3 where we showcase the flow of our architecture previously illustrated in Figure 1. Two users with AR devices have their own Solid Pod. User 1 will create an environment ( ) on their Pod and subscribe to the inbox container of this environment. Once the environment is ready, the AR device will use the SemBeacon specification to advertise the URI of the environment and enable its discovery.
When another user (e.g. user 2) discovers the resource URI, the AR application will access
the environment to visualise the augmented objects. If user 2 makes a modification such as
adding virtual objects, these modifications are stored in the Pod of user 2 as environment ′,
ensuring ownership of this contribution and enabling user 2 to choose the access rights to this
modification. To keep up-to-date with changes in the original environment, the application will
listen for changes in the inbox of environment . All users who are subscribed to this inbox
will receive linked data notifications [
An inbox uses the LDP1 vocabulary to index all resources within this container. A user who
wishes to accept contributors for their environment should configure this inbox container with
public append access rights, giving other users the opportunity to append a new resource to
the container. Each inbox item represents an action using the schema.org vocabulary [
Listing 1: Inbox item to identify the creation of a virtual object
Listing 1 demonstrates an individual appended inbox item to the Solid Pod of user 1. In the
example we see a schema:CreateAction indicating that user 2 created a new painting object.
Users can listen for notifications in the inbox to automatically apply changes to virtual objects
in the shared AR environment as they are made [
The positioning of virtual objects is done using the POSO ontology [
The final AR environment, combining all modifications made by other users, is created by the AR application that has access to the Solid Pod. Our architecture allows users to easily ignore all contributions of another user or agent. Individual modifications or contributions can be rejected by ignoring the individual inbox items where these changes are referenced. Future work might address the moderation of individual contributions by applying quality assessment crowdsourcing techniques [17].
Augmented reality uses one or more reference frames [
In order to enable interoperable applications to contribute to the same environment, all applications need to operate within the same reference frame. Our solution assumes that contributions to an environment not only include virtual objects, but also additional anchor points such as markers and detectable features contributed by multiple users [18]. By semantically describing these reference frames as visual landmarks rather than a frame of reference, the POSO ontology can be used to position virtual objects relative to these anchors.
Solid enables users to control the access rights to their data and resources. In the scope of our solution, this entails the data shared in the AR environment (i.e. virtual objects and anchors) by both, the user who owns the environment and users who make their own modifications to the environment.
Each modification to an environment is made in the Solid Pod of the user who made the modification, giving them full control of the access rights to these modifications, as well as control on the actions which are usually created in the original environment to notify the original owner of the environment (see Section 2.1).
We presented a solution enabling the collaboration and sharing of personal augmented reality environments by using Solid Pods. Our solution allows these personal AR spaces to be discoverable within the physical space that they are augmenting by means of semantic beacons that advertise a URI. The URI directs to the environment that is currently being shared by a user. This user has full control over who can access the environment or who can contribute their changes. While our proposed solution allows users to choose which collaborators to accept for the environment through the inbox system, it is currently impossible to accept individual contributions from a single collaborator. Future work might address this issue by applying crowdsourcing techniques [17] to the data that is produced by other users.
In this paper, we focused on the passive discovery of AR environments using BLE advertisements to enable seamless discovery of the linked data. Similar architectures can be designed using other discovery methods such as a QR code on the door of the environment or network discovery protocols such as UPnP [19]. In the future, we might compare the performance between keeping multiple versions of a virtual environment in diferent Pods (as proposed in our solution) and the use of a stream of events indicating changes to the environment, similar to the work proposed in [20]. [17] M. Acosta, A. Zaveri, E. Simperl, D. Kontokostas, S. Auer, J. Lehmann, Crowdsourcing Linked Data Quality Assessment, in: Proceedings of the 12th International Semantic Web Conference (ISWC 2013), Sydney, Australia, 2013. doi:10.1007/978- 3- 642- 41338- 4_17. [18] M. Van de Wynckel, I. Valadez, B. Signer, FidMark: A Fiducial Marker Ontology for Semantically Describing Visual Markers, in: Proceedings of the 21st International Conference on the Semantic Web (ESWC 2024), Hersonissos, Greece, 2024 (In Press). [19] J. M. S. Santana, M. Petrova, P. Mahonen, UPnP Service Discovery for Heterogeneous Networks, in: Proceedings of the 17th International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC 2006), Helsinki, Finland, 2006. doi:10.1109/PIMRC. 2006.254286. [20] W. Slabbinck, R. Dedecker, S. Vasireddy, R. Verborgh, P. Colpaert, Linked Data Event Streams in Solid LDP Containers, in: Proceedings of the 8th Workshop on Managing the Evolution and Preservation of the Data Web (MEPDaW 2022), Online, 2023. URL: https://ceur-ws.org/Vol-3339/paper4.pdf.