Telepresence basics

Business team talks about working in videoconference

Business team talks about working in videoconference

When designing and installing telepresence systems, a range of environmental and client-specific variables should be considered. Jacob Harris takes a look at what is required.  

The ultimate goal of a telepresence system is to make multiple users in remote locations feel as though they are conversing with each other in person. A step up from traditional telephony, telepresence aims to create an accurate environmental semblance between locations. To achieve this, the audio and visual output provided by the system need to match the user’s immediate environment as closely as possible.

“The central idea is to reduce the differences between sites – everyone’s experience should be the same no matter where they are in the world. We usually break it down into categories of audio, video, and possible server types,” says InfoComm University staff instructor Andre LeJeune.

Clear audio is fundamental to any effective communications platform, and this is especially true when it comes to telepresence. To achieve high fidelity audio transmission, room acoustics, ambient noise, microphone choice and positioning all need to be carefully considered.

“People using these systems are supposed to think that they are speaking right across the table to someone who’s sitting on the other side. If the room has so much echo or reverberation in it that it won’t support a quality audio system then you’ve lost half your battle right there,” says Andre.

With this in mind, one of the first things to look at is the acoustics of the space the system will be installed in. Factors such as ambient noise from air conditioning or heating systems and reflective wall surfaces can significantly degrade a system’s audio quality.

“Many rooms are acoustically challenged due to their design or surrounding environment. That is where advanced audio technology, experience and design guidelines play a vital role in providing the end user with the best audio experience while in a video conference,” says Polycom APAC director of industry solutions and market development Tony Sandberg.

“Finding rooms with the least amount of ambient noise should be the first priority. Sometimes those options are limited but once the room has been selected, microphones should be placed away from noises that would affect the quality of the audio such as air-conditioning vents, projector power supply fans and laptop power supply fans.”

Once extraneous noise has been mitigated, the next challenge is to make the audio sound as natural as possible. There is a plethora of microphone options available on the market and the final choice will largely come down to budget and personal preference. However, one piece of advice InfoComm gives to integrators is that reducing the distance between the audio source and the microphone will help to reduce the ambient sound, so lapel and headset microphones are good choices.

As an alternative to using a dedicated audio output device, the technology used for zoned audio systems can also be applied when designing a telepresence system. The ability to calibrate a zoned system’s speakers to their physical position in a room and employ echo cancelling technology can aid in achieving clearer audio and a more ‘natural’ experience overall.

The size and positioning of visual displays is also dictated by the objective of achieving an experience that is as true to life as possible. To this end, displays should be positioned so the person on the screen is at the same height and scale as they would be if they were physically in the room.

“The idea is that someone looking across the table should see their interlocutor in a 1:1 scale. The suggestions from the information we’ve gathered is you should base the display size on whether or not you want the person’s head, which is approximately 20 – 22cm in height, to occupy either half or one third of the screen and then you determine the size of the display based on that,” says Andre.

When deciding on camera positioning the same principles should be considered, so the angle of the lens should approximate the position of the human eye as closely as possible. Having cameras high up on the wall zooming in does not fit the model as well as having the cameras at eye level so that everyone on both the sending and receiving end is effectively looking at each other right in the face.

“Architectural specifications for camera position are often based on the average height of a human head. Alternatively the cameras can be made to move up and down. The idea of getting the image true to life is really big right now because it’s extending video conferencing by adding a spatial element. A lot of people in the industry are waiting to see who’s going to find the best way to do it,” says Andre.

As far as networking requirements go, Session Initiation Protocol (SIP) and H.323 are the protocols most commonly used. SIP is the more flexible of the two and will support a range of applications including instant messaging and voice over IP (VoIP). On the other hand, H.323 is designed specifically for multi-media communications and is ideal for applications like setting up audio and video calls, registering terminals and holding multi-point conferences or for areas with infrastructure issues.

“Generally, the recommendation is for IP networks to be built with <100ms round trip delay between sites for video conferencing rooms. That being said, some developing countries may still face infrastructure issues. Polycom has built technologies such as H.264 high profile that uses less bandwidth for high quality calls and loss packet recovery (LPR) for unreliable networks. This helps in situations where limited bandwidth is available or in a highly contended network environment,” says Tony.

Of course, it’s also important to factor in the potential uses of the system. Will it be used for one-on-one conversations, presentations or group collaboration? Each scenario has its own set of unique challenges. The technology will be used differently if it is used by a teacher for education or if it is used by a research and development team in a manufacturing company. The system should ultimately be designed with the workflow and the user in mind.

“We find that among our [InfoComm] membership we have a lot of arguments with our subject matter experts about the best way to implement a telepresence system while observing a client’s financial limitations. There’s not yet a set of rules that defines exactly what a good telepresence environment is. System design and installation has so many facets to it depending on what the client wants and needs from a system,” says Andre.

As communications technology develops, the traditional office is giving way to more open, shared and cost-effective combinations of public and private spaces – productivity and collaboration no longer depend on a shared physical location. With all variables considered, an effectively designed telepresence system will enable users to engage, participate and innovate from remote locations via secure connections across the world and feel as though they are speaking across the room.

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Reference: Connected Home

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