Diego Vaquero-Melchor

Augmented Reality (AR) functionalities may be effectively leveraged in collaborative service scenarios (e.g., remote maintenance, on-site building, street gaming, etc.). Standard development cycles for collaborative AR require to code for each specific visualization platform and implement the necessary control mechanisms over the shared assets. in order to face this challenge, this paper describes SARA, an architecture to support cross-platform collaborative Augmented Reality applications based on microservices. The architecture is designed to work over the concept of collaboration models which regulate the interaction and permissions of each user over the AR assets. Five of these collaboration models were initially integrated in SARA (turn, layer, ownership, hierarchy-based and unconstrained examples) and the platform enables the definition of new ones. Thanks to the reusability of its components, during the development of an application, SARA enables focusing on the application logic while avoiding the implementation of the communication protocol, data model handling and orchestration between the different, possibly heterogeneous, devices involved in the collaboration (i.e., mobile or wearable AR devices using different operating systems). to describe how to build an application based on SARA, a prototype for HoloLens and iOS devices has been implemented. the prototype is a collaborative voxel-based game in which several players work real time together on a piece of land, adding or eliminating cubes in a collaborative manner to create buildings and landscapes. Turn-based and unconstrained collaboration models are applied to regulate the interaction. the development workflow for this case study shows how the architecture serves as a framework to support the deployment of collaborative AR services, enabling the reuse of collaboration model components, agnostically handling client technologies.

Nowadays, Augmented-Reality (AR) head-mounted displays (HMD) deliver a more immersive visualization of virtual contents, but the available means of interaction, mainly based on gesture and/or voice, are yet limited and obviously lack realism and expressivity when compared to traditional physical means. In this sense, the integration of haptics within AR may help to deliver an enriched experience, while facilitating the performance of specific actions, such as repositioning or resizing tasks, that are still dependent on the user’s skills. In this direction, this paper gathers the description of a flexible architecture designed to deploy haptically enabled AR applications both for mobile and wearable visualization devices. The haptic feedback may be generated through a variety of devices (e.g., wearable, graspable, or mid-air ones), and the architecture facilitates handling the specificity of each. For this reason, within the paper, it is discussed how to generate a haptic representation of a 3D digital object depending on the application and the target device. Additionally, the paper includes an analysis of practical, relevant issues that arise when setting up a system to work with specific devices like HMD (e.g., HoloLens) and mid-air haptic devices (e.g., Ultrahaptics), such as the alignment between the real world and the virtual one. The architecture applicability is demonstrated through the implementation of two applications: (a) Form Inspector and (b) Simon Game, built for HoloLens and iOS mobile phones for visualization and for UHK for mid-air haptics delivery. These applications have been used to explore with nine users the efficiency, meaningfulness, and usefulness of mid-air haptics for form perception, object resizing, and push interaction tasks. Results show that, although mobile interaction is preferred when this option is available, haptics turn out to be more meaningful in identifying shapes when compared to what users initially expect and in contributing to the execution of resizing tasks. Moreover, this preliminary user study reveals some design issues when working with haptic AR. For example, users may be expecting a tailored interface metaphor, not necessarily inspired in natural interaction. This has been the case of our proposal of virtual pressable buttons, built mimicking real buttons by using haptics, but differently interpreted by the study participants.

This paper describes a Mission Definition System and the automated flight process it enables to implement measurement plans for discrete infrastructure inspections using aerial platforms, and specifically multi-rotor drones. The mission definition aims at improving planning efficiency with respect to state-of-the-art waypoint-based techniques, using high-level mission definition primitives and linking them with realistic flight models to simulate the inspection in advance. It also provides flight scripts and measurement plans which can be executed by commercial drones. Its user interfaces facilitate mission definition, pre-flight 3D synthetic mission visualisation and flight evaluation. Results are delivered for a set of representative infrastructure inspection flights, showing the accuracy of the flight prediction tools in actual operations using automated flight control.