# A Review on Methods and Systems for Remote Collaboration
###### Abstract  
Due to the appearance of COVID-19 in 2019, person-to-person interactions were drastically reduced. The impact of these restrictions on the economic environment was significant. For example, technical assistance for commissioning or adjusting the parameters of some complex machines/installations had to be postponed. Economic operators became interested in the possibility of remote collaboration, depending on the manufactured products and the performance of the production lines that they owned. This bibliographic research was undertaken to address these needs. The purpose of this review was to analyze the current solutions, approaches, and technologies that workers and specialists can implement to obtain a reliable remote collaboration system. This survey focuses on techniques, devices, and tools that are being used in different contexts to provide remote guidance. We present communication cues and methods being employed, the implemented technological support, and the areas that benefit from remote collaboration. We hope that our effort will be useful to those who develop such systems and people who want to learn about the existence of collaborative solutions, and that it will increase awareness about the applications and the importance of the domain. We are convinced that, with the development of communication systems, the advancement of remote support systems will be a goal for many economic operators. remote assistance; smart device; video camera; mixed reality; virtual reality; augmented reality; communication cues; 360-degree panorama; annotation; object manipulation +
Footnote †: journal: Applied Sciences  
concerns in this field but will not be detailed as they are not considered the subject of this paper. As a general rule, industrial processes such as manufacturing, assembly, packing, etc., are in a race against the clock. To sustain the process and the infrastructure, facilities and installations need to function without error almost 24 h a day, 7 days a week. Given these time constraints, every outage must be immediately solved. Occasionally, detailed information is vital for a remote expert to comprehend the situation and guide a less experienced person accordingly. For example, during a remote assistance session, there is a fundamental need to identify specific targets, boundaries, devices, and parts. It is crucial to be able to discuss the defects, take corrective actions to remove the causes of the malfunction, and restore the system to a perfectly functioning state. Performing the correct actions is important as human error, accidents, and outages can damage devices or chains of systems. Overall, a holistic view of the system is needed so that, while corrective actions are taken to address specific problems, we keep in mind the whole picture of the process and are not limited to only the observed symptom or the small scope of the issue. These remote assistance situations can be found in the medical field, such as surgery [1; 2; 3; 4; 5; 6; 7; 8; 9] and emergency management [10], in the education sector [11; 12], mining [13], food industries [14; 15], manufacturing industries [16; 17; 18; 19; 20; 21], and crime scene investigations [22]. For the last 20 years, researchers have tried to find new ways to allow a remote (i.e., located in a different location) user/expert to help an on-site user by sharing the local user's view in real-time, thus improving the workspace awareness for the expert. In early studies, different setups involving head-mounted cameras, head-mounted displays, video cameras, and pointing devices were developed to facilitate communication between two remote users. Lately, researchers have been focused on systems that rely on smart glasses and head-mounted devices based on augmented reality and virtual reality. Furthermore, there is interest from large companies around the world in developing devices that support real-time remote assistance and remote training for front-line workers [17; 18; 19; 21].