Measuring the counting accuracy of Terabee Time-of-Flight people counters
In this article, we will examine the technical aspects of how counting accuracy is measured with Terabee Time-of-Flight people counters, exploring the underlying principles, challenges, and evaluation methodologies used.
Principles of Time-of-Flight people counters
Time-of-Flight (ToF) people counters rely on a combination of infrared (IR) light and ToF technology to determine the distance of objects within their field of view. Time-of-Flight sensors work by emitting a light signal and measuring the time it takes for the signal to reflect back to the sensor. This time measurement is then used to calculate the distance between the sensor and the object or person in the field of view.
To accurately count people using Time-of-Flight sensors, the sensors must be able to distinguish between people and other objects in the environment. This is achieved by using advanced algorithms that can differentiate between the size and shape of people and other objects. The algorithms are also designed to filter out noise and false readings to ensure accurate counting.
Factors that affect people counting accuracy
Some of the main factors that influence the accuracy of Time-of-Flight people counters are:
Device orientation and placement: The positioning of Terabee people counting sensors plays a crucial role in ensuring accurate counts. Optimal placement minimizes blind spots and maximizes coverage. Please refer to the device user manual to ensure that device orientation and placement is optimized.
Sunlight exposure: The Time-of-Flight technology relies on the emission and reception of infrared light, which overlaps with some of the sunlight radiation. For this reason, sunlight may affect the device’s operation.
To avoid any problem, Terabee’s recommendation is to install the device inside your building where the sun’s reflection cannot be projected onto people’s head and shoulders. If it’s not possible to install the device this way, you may try the following:
- Lower the installation height to minimize the impact of the direct sunlight on the field of view
- Place non-reflective flooring in the exact place where sunlight hits the ground
Obstacle and external infrared sources:
- Avoid placing the Terabee People Counting L-XL above ‘Exit’ signs or any obstacles that could block the field of view or create interference
- On some rare occasions, other infrared sources, such as automatic door sensors or security cameras, can impact the device’s operation. If you observe abnormal counts or a highly affected infrared image (black pixels), move the device and check if the problem persists
Distance resolution: The precision with which the Time-of-Flight sensor can measure distances affects counting accuracy. Higher distance resolution allows for more precise distance estimations, reducing errors in counting.
Ambient light interference: Ambient light can interfere with IR signals, leading to inaccuracies in distance measurements. Advanced ToF sensors employ noise reduction techniques to mitigate these effects.
Multiple objects: Differentiating between individuals in crowded scenarios can be challenging. Tracking algorithms must be robust enough to handle occlusions and identify unique individuals accurately.
Measurement methodologies
To evaluate counting accuracy of Terabee ToF people counters, various methodologies are employed:
Controlled testing: One of the most reliable methods involves creating a controlled environment. Terabee experts manually count individuals passing through the sensor’s field of view and compare it with the system’s output.
Real-life use case accuracy testing: To validate counting accuracy in real-world scenarios, Terabee ToF people counters are deployed in multiple live environments which cover most use cases. The system’s performance is compared against manual counts or data from other counting methods.
Accuracy testing for Terabee People Counting devices
People Counting L-XL
Based on a solid methodology Terabee has performed a series of various tests with a significant number of data points, to support the following findings:
- Within the installation guidance and specifications, the People Counting L-XL device consistently reaches a typical counting accuracy of 98% or more, in most conditions
- In the same conditions, the PCL-XL in a multi-device installation reaches a counting accuracy of 98%
- Specific light conditions, and door materials impact to various degrees the PCL-XL accuracy, which can then decrease below 98%
The conclusion is that these tests, for both single device and multi-device installation, and the real-life use case accuracy tests support Terabee’s claim for typical 98% people counting accuracy.
People Counting M 2.0 LoRa
As for PC L-XL, Terabee experts have performed tests with the same standards of strictness, leading to the outcome below:
- Within the installation guidance and specifications, the People Counting M 2.0 LoRa device reaches a counting accuracy of 95% or more
- Specific light conditions, and door materials impact to various degrees the People Counting M 2.0 LoRa device accuracy, which can then decrease below 95%
The conclusion is these tests and the real case accuracy check support Terabee’s claim for typical 95% people counting accuracy.
Time-of-Flight people counters from Terabee
Terabee is a leading provider of people counting sensor technology that uses ToF sensors. The company’s sensors are designed to be accurate, reliable, and easy to install. The sensors use advanced algorithms to filter out false readings and noise and provide accurate counting in a variety of settings. All data is fully anonymous, privacy-respecting and GDPR-compliant.
Terabee’s people counting sensors are designed to be highly adaptable and can be used in a variety of settings, including space and flow monitoring in commercial real estate settings, operations optimization in company canteens and staff dining rooms, and smart university campuses.
With its ability to aggregate data taken from up to five separate sensors, the Terabee People Counting L-XL device offers easy installation and configuration. It is a highly accurate solution to gather data on people flow at large doors, entrances and indoor gates, such as auditoriums and large theatres. Its smaller sibling, the Terabee People Counting M 2.0 LoRa device is suitable for standard doors and narrow corridors, such as in meeting rooms and washrooms.
Contact us if you’d like a copy of the Terabee People Counting Accuracy test report. Speak to an expert about your people counting challenges and requirements, request a quote or get a product demo. Get in touch today!
