Sync Surveillance with Sound

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When discussing audio’s value proposition with your leadership, frame it as avoided costs, recommends Brent. What’s it worth to your organization to prevent one altercation from going further than it should? The financial repercussions of compromised security can range from property destruction and theft to more serious instances of legal liability if people are injured. The combination of video and audio puts additional data into the hands of your security team so they can assess and respond with speed.

Aside from sensitive areas where the expectation of privacy is a given, such as restrooms and locker rooms, audio has no physical limitations in your building. You can use electronic ears in a host of external applications, from entrances and loading areas to parking lots and perimeter zones. Camera mics are equally as useful inside your facility, including lobbies, work areas, classrooms, corridors, stairwells, cafeterias and gyms. Anywhere you have a security camera can be optimized with sound as well.

One caveat is how much background noise is present. For example, traffic noise may interfere with audio quality if your property is near a busy road. An open work area with echoes or a factory with loud equipment could impede sound recognition in a similar manner. An apt example where audio‘s effectiveness is rendered mute – a sports venue. A place where people normally cheer, scream and yell will make it hard to detect legitimate aggression from enthusiastic fan behavior, says Brent.

No matter where you want to place audio, first determine what you want to hear (see sidebar below). Is it a matter of listening in real time when warranted or letting software determine when an unusual sound has occurred? This seems like a simple question, but the answer will dictate what type of listening technology you need.

The Right Equipment

While sourcing audio equipment is relatively straightforward, pay close attention to its installation. Microphone placement is different than field of view. The best place for a camera is usually in the corner of a room and high out of reach, but sound isn’t contained at the edges of a space, Brent notes. Unless you have a sophisticated audio capture device that can pick up sounds from the middle of the room, the audio could be garbled, distorted or out of sync with the video. In these cases, you can run the cabling for a plug-in microphone behind the walls or ceiling so you can place the mic in an effective location separate from the camera.

Also consider that all microphones are not created equal. For example, a mic used by a singer is designed to capture a different set of audio frequencies than the sounds needed beyond the human ear for surveillance purposes, says Brent. A poor quality microphone is about as useful as a poor quality camera. Depending on what you want to register, you may need more advanced microphones that have a high sensitivity and can filter out ambient noise, suggests Steve Surfaro, Industry Liaison for Axis Communications.      

But don’t forget about the camera itself – the video is the foundation for audio. To achieve the right balance of visual and audio acuity, you need a strong resolution to have clear footage and the right audio capabilities to process cascading sounds, Surfaro explains. Owners with CCTV or a mix of analog and IP equipment will have to work around their existing systems to achieve useable audio. If your video is for general observation, a full system upgrade may not be required – microphones will be able to distinguish classes of objects in the field of view, recommends Surfaro. If you want to isolate individual sounds, however, installing HDTV cameras with quality microphones can aid in forensic investigations.

Another functionality you may want to secure is two-way communication. Not only will you be able to listen to an area, but you can deliver live messages using the same speaker equipment, Surfaro says. In a crisis, voice communication can deliver instructions or reassurance to occupants as you keep visual and audio tabs on the situation. If an individual is detected committing violence or vandalism, you can tell them to cease and desist and that security is responding to their location.

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Video Intercoms to Control Access

What if you want to use audio in a more interactive way? Video intercoms allow you to see and hear people as they approach an entrance. These dynamic devices can interface with your badging system so you can communicate with individuals as an added layer of authentication.

“Video intercoms are a bridge solution between access control and surveillance, says John Mosebar, Vice President of Aiphone, a communication systems provider. “They enable you to engage with what you see.”

The systems are typically standalone and don’t need to be networked, which simplifies installation. They are routinely used at external entrances, both main and back doors, and can capture images during low light and darkness, says Mosebar. You can also use them internally for restricted areas. There are also software solutions that run on a computer or mobile phone, a useful solution to reduce hardware on a reception desk and simplify guest verification, he adds.

One key advantage is the field of view. Security cameras are traditionally placed high in a corner so they have wide coverage – useful for monitoring perimeters but not for verifying identity. Video intercoms, on the other hand, are placed at eye level because the depth is intentionally shallow to capture faces. Individuals will also approach the station directly so a front view can be achieved.

In terms of operational efficiency, video intercoms are a time saver because badging issues can be resolved remotely, Mosebar explains. Your security team can provide instant assistance if a person’s access is denied. He or she could hold up a photo ID for verification or say a preapproved security phrase to gain entry.

Beyond access control, video paging can amplify the effectiveness of emergency or push-for-help stations, adds Mosebar. These devices are traditionally configured as a distress button or a call station with two-way communication, but the only way you can see that location is to have a separate surveillance camera in the vicinity. With a video intercom feature, however, you can visually monitor the location while receiving and sending information.  

Distinguish Threats with Analytics

Video analytics can already interpret physical movement and audio analytics are no different. Much research has gone into mapping the human ear and watching how the cochlea transmits sound waves to the brain as nerve signals. Software algorithms replicate this biological process in order to identify signature sounds. These apps can flag anything from cries of distress and vocal aggression to the sounds of vehicle crashes, breaking glass or weapon discharges, Surfaro says.

Note that these programs are a form of audio recognition – they’re not continuously listening to every single noise, stresses Surfaro. Only predefined or unexpected noises will trigger the software to send an alert to your security team. And unless the software is supposed to recognize key words, aggression detection is limited to vocal inflections rather than word choice. Not only does this allay speech privacy concerns, but it saves on bandwidth because the app doesn’t need to stream all the time.

Using analytics to identify specialized sounds helps you to respond more quickly. A few seconds saved over scrutinizing a silent video capture can get guards on location more nimbly or a 911 call dispatched earlier. It’s the difference between responding to a physical fight in progress and preventing verbal aggression from escalating to battery.

You can also put sound detection to use outside of your security operations. In industrial or mission critical settings, you can teach the analytics to recognize the hum of your machinery, Surfaro explains. If a machine runs outside of business hours, makes an unusual noise that points to a maintenance issue or goes silent when it should be on, the analytics will know and send a notification.

Another smart use of this capability is in parking areas. While gunshot detection has become more prevalent in recent years, don’t overlook more common occurrences like car accidents that affect life safety, says Surfaro. It’s far more likely that a fender bender will happen on your property than mass violence. In addition to recognizing the distinct sound of cars hitting one another, analytics can detect car alarms and breaking glass. Thieves may think twice if someone can hear them breaking into a vehicle and occupants can take comfort that their car is less likely to be stolen or vandalized.

No matter which sound capture option you use, adding audio will help solidify your due diligence. “You should do everything in your power to make your facility safer,” says Surfaro. “If you have the capability for audio, why not use it to your advantage?”

Jennie Morton [email protected] is Senior Editor of BUILDINGS.