# A Review on Methods and Systems for Remote Collaboration
## 3 Electronic Devices Used in Remote Assistance
The proxy object is automatically oriented by a robotic arm to reflect the position from the tracking site. SharedSphere, proposed by [PERSON] et al. [55], uses mixed reality (MR) to add gestures and cues to a 360-degree live panorama video. The local user wears a see-through AR HMD with an attached 360-degree video camera. The guest user wears a virtual reality (VR) HMD to watch the live panorama scene. A head tracking sensor is mounted on the host's side so that the remote user can have an independent view of the local user's environment even if the local user moves his head. The system uses view frames to indicate where each user is looking. [PERSON] et al. [56] addressed the use of multi-cameras for remote collaboration. The study compared the efficiency of using handheld devices over the hands-free experience in the context of using multiple video cameras. The system is composed of three types of cameras focused on the room (space), task, and the collaborator's face. Cameras could be switched manually or automatically depending upon the activity in the room. The study showed that task performance was the same when using handheld devices compared with when the user had his hands free, but users preferred the flexibility of the hands-free setup. In the context of an industrial environment, [PERSON] [16] proposed a video collaboration platform for remote interaction based on mobile devices and web cameras. The system has three main components: a dashboard receiver, a cloud service, and a plant operator. If a worker needs assistance in configuring industrial equipment, the machine's information is loaded onto a dashboard receiver, where it can be accessed by a remote expert. A cloud service hosts the APIs, which the collaborators can access to connect to the dashboard and operate. The system allows the operator to connect with the expert using a tablet device with a camera and to point the camera at the malfunctioning equipment. The collaborators can exchange information through video and audio channels and text messages through the chat functionality. [PERSON] et al. [57] defined a fully asymmetric remote collaboration system where the remote user identified the local user's problem and had full control of the worker's environment while the worker had limited responsibilities. On the local user's side, a wheeled robot controlled remotely by a handheld device was equipped with a projector, a high-resolution camera, and a 360-degree camera. The remote user wore an HMD device that displayed information about the local user's surroundings captured by the robot. The  
Figure 5: Gutsy-Avatar [53] system diagram. remote user was capable of zooming in and out, pointing to objects, or adding annotations that could be projected onto the local user's environment. The system proposed by [PERSON] et al. [58] is composed of an AR HMD device with a 360-degree camera on top, on the local user's side, and a VR HMD on the remote user's side. The local user captures 360-degree panoramas of the local environment and sends them to the remote user, where they are displayed as a prebuilt 3D scene. Verbal communication is accomplished through the speakers of the HMD, and for non-verbal communication, the remote user can use the VR controller for pointing and instructing the local user. OmniGlobe [59] uses a VR HMD device on the worker's side and, on the other side, a spherical display with a 360-degree camera, which is located on a rotating platform, allowing the specialist to move around. The system has a 360-degree first-person mode that allows the expert to see the VR environment from a panoramic view, and a third-person mode makes it possible to see the environment from a higher elevation. Communication is enhanced by the system's ability for the users to share body gestures, gaze cues, and facial expressions. [PERSON] et al. [60] proposed an MR collaboration system using mobile devices that uses light fields for orientation.