# A Review on Methods and Systems for Remote Collaboration
## 3 Electronic Devices Used in Remote Assistance
Both users could take snapshots, and the stream could be frozen on either side when one of the users wanted to point at a particular scene at a chosen moment. PopArm [39] is a solution based on a robotic arm that seems to pop out from a video streamed between two remote users. The robot arm is synchronized with the remote instructor's arm movements, and it moves and rotates on the local user's display, enabling the off-site user to point to and touch remote objects in the local user's environment. PopArm is useful when there is a need to point to specific objects remotely. RemotIO [40] consists of two head-mounted cameras, one for the helper and one for the novice user. The local user shares his view; the video is then used for immersing the expert into the worker's field of view. The expert's hands are tracked with a depth sensor and superimposed in real time onto the worker's environment. The local user's hands and the superimposed expert's hands can be seen by both users. RemotIO aims to be used in the industry for remote maintenance and repair. ExpertOnWheels [41] is a mobile telepresence robot designed to support collaboration between a field worker and a remote expert in the manufacturing industry. The architecture of the collaboration system is showcased in Figure 4. The mobile robot comprises a video camera for capturing the environment's details, a projector used for annotations, a speaker, a microphone for sound, and wheels for movement. A computer is the processing brain of the ExpertOnWheels (worker's side), which receives commands via the internet from the remote expert's PC controls. The local worker moves the robot only where intervention is needed. To determine the task efficiency when collaborating remotely, [PERSON] et al. [42] conducted a comparative study for the use of handheld devices and head-mounted devices (HMD). The conclusions showed that, for static tasks, handheld devices were more suitable, but for dynamic tasks, head-mounted devices helped the user to finish a task faster. In another article, [PERSON] explored how the field of view impacts collaboration [43]. In this study, a robot controlled by a remote participant captured the distant environment at different angles. The results indicated that using a wide angle and a panoramic view contributes to quicker task completion. The JackInHead system [44] tries to overcome the field of view limitation of the remote user by using headgear with multiple cameras to capture an omnidirectional video. The local user wears the headgear, while the remote user wears a head-mounted display with head tracking functionality. [PERSON] and [PERSON] [45] investigated how the independent view helps users to finish tasks faster when using an AR interface. The prototype allowed a remote user to navigate independently in the local user's space using a 3D scanned model of the local user's environment. The local user wore a head-mounted display that helped to render the annotations of the remote user. A four-video-camera system was used to track the objects from the local environment and the head movements of the host. Smart Phone/Pad and Robot for Tele-operation and Tele-presence (SPRinT) [46] is another remote collaboration system using a robot located at a local user's site. The robot is equipped with a video camera and a projector to display the instructions of the remote user. The local user can adjust the robot and the projector position while the expert controls it using a mobile phone. Figure 4: System architecture diagram for ExpertOnWheels [41]. ADAMAAS [47] aims to determine the local user's actions in order to trigger instructions that are displayed as visual images or text on the HMD worn by the respective user. The system is composed of a head-mounted display with AR capabilities and an eye-tracking module. In order to increase the situational awareness of the remote user, [PERSON] and [PERSON] [48] focused their research on improving the user's view using a mobile telepresence robot situated at the worker's site.