Q&A on Terabee People Counting systems

Here we give you the questions we get asked most frequently about people counting technology, and how our people counting solutions can be integrated into your systems. If you can’t see your question here, please contact one of our technical experts.

How do Time-of-Flight people counters work?

The Time-of-Flight (ToF) principle is a method for measuring the distance of an object from a sensor. It lies at the heart of Terabee’s people counting systems. The sensor on the IoT hardware device emits near-infrared light that is invisible to the human eye.

When the light hits a surface it is reflected back to the sensor. Because we know the speed of light, the time taken for the light to be emitted and received back enables us to precisely calculate a distance at very high speed and many times per second.

Each pixel of the sensor is therefore a distance measurement in millimeters, which results in a global depth map that can be used to detect forms and shapes, like humans.

What are the advantages of Time-of-Flight people counters? Can the Terabee People Counting device count when there is no light?

3D Time-of-Flight sensing has a number of advantages. Because it does not capture a RGB image, like stereo vision systems, it is GDPR-compliant by design and user anonymity is guaranteed. Our technology also works just as well in low light conditions, and a broad range of temperatures. Subsequently counting accuracy is far higher. It is common for us to attain 95% accuracy and above.

How does Terabee’s people counting technology accommodate two people passing through a door at the same time?

The People Counting L-XL device is able to track multiple people within its Field of View. If two people pass below the sensor simultaneously, it will count two people correctly. 

The People Counting M device is only able to track one person at a time. That’s why we recommend only deploying this device in narrower, standard sized doors.

Is there a minimum distance for the sensors to distinguish two people passing below?

There is no minimum distance for the People Counting L-XL. The device will distinguish two people even when they are positioned extremely close together. 

The People Counting M is only able to distinguish two people if there is at least 30 centimeters between them.

What is the Field of View?

The People Counting L-XL features a large detection area of 74° x 57°. When mounted at 4.0 m high, the people counting sensor will detect an area that is 3.4 m wide. When five devices are installed in a series, the sensors will detect an area more than 15 meters wide. 

When installed between 2.3 to 3.0 meters high, the People Counting M detects an area of up to 0.9 m wide with a Field of View of 15°.

What are the power requirements for the sensors?

The People Counting L-XL uses a standard Power over Ethernet (PoE) supply.  The People Counting M can use PoE as well as a 5 V power supply.

Do I need to calibrate the people counting device on installation? And how often do I need to recalibrate the sensor?

There is no calibration necessary on installation. The devices are calibrated during the production process. The only thing you need to calibrate in the settings is the height of the device from the floor. There shouldn’t be any requirements to recalibrate or change settings during the lifetime of the product.

How do I configure and integrate the Terabee people counting devices?

Everything is included within the devices, from the depth image to counting detection and counting algorithm. The devices also host a local web interface that can be easily accessed by any WiFi-enabled device. This gives immediate access to all relevant parameters for easy configuration and set-up, such as installation heights, counting area definition, data push features and multi-device configuration.

Once installed, people counting devices can either be connected via Terabee’s IoT Platform or easily integrated into existing platforms via a direct data transmission in HTTP or MQTT. This enables multiple spaces and entrance or exit points to be monitored together.

Do any APIs exist?

Terabee provides an API to retrieve the counting information available on the IoT platform.

To access the API, you need to register to the Terabee IoT Platform services. You will be able to access occupancy, Entries, Exits and to create sensor association with rooms and buildings.

How does the Terabee people counting device communicate and integrate within a Building Management System (BMS) software?

When the device is installed, it is set up to immediately start counting. Everything is included within the device, from the depth image to counting detection and counting algorithm. The data is transmitted on a LAN network, either through ethernet or WiFi, via HTTP or MQTT protocols to a host. The host can be a local server, a web server or a cloud platform. 

Our people counting system can also be connected to a Building Management System (BMS) or any other system software (such as a meeting room booking system). The middleware between our device and the BMS aggregates and computes the data and creates any triggers required for the BMS, such as triggers to adjust heating or ventilation within the system.

Data integration to trigger Smart Building controllers:

Source: Terabee

Is there a reset count to mitigate errors? How does it work?

Terabee People Counting M and L-XL devices are respectively 95% and 98% accurate in typical situations. This is why, to avoid cumulative errors over days, a configurable reset function comes with our products which applies a reset on the counts when the building is empty (at noon by default, but the reset hour can be different depending on the user needs)

What happens if power is cut or the device goes down? Are the counts kept?

Counts and parameters are saved even when power is cut. The device will not count during the cut-off period but it will recover the last counts when booting up again. Depending on the timing it will proceed with a count reset or keep counting with the last registered counts. But the counts will be retrieved from before the event when it boots up if it is the same day, otherwise it restarts to 0 as a reset hour period started.

If the Internet connection is cut, the People Counting L-XL is stocking the MQTT messages and will push them all when the Internet is back. It can store up to one week of messages. The People Counting M will only push the last message when the connection is cut.

How many sensors does my building need per room/space for counting?

Terabee people counting devices are installed above doors and passageways. Therefore you may consider every point where people are passing and where it is interesting for you to know the number of passages. To know the occupancy of a space, you need to cover all the entrances and exits to have accurate metrics. Our team will be happy to help you assess the number of devices if you can share a floor map.

Is the Terabee People Counting L-XL suitable for my business and industry?

We recommend our People Counting L-XL for indoor environments use and in the smart building (commercial, residential, tertiary building) or retail sector.

Is the Terabee People Counting M suitable for my business and industry?

We recommend our People Counting M for indoor environments use and in the smart building (commercial, residential, tertiary building) or retail sector.

For more information visit our People Counting page, or talk to a member of our team to find out more or schedule a demo.