Fluke Process Instruments

Occupancy Measurement Methods

The Occupancy of an area can be measured by several techniques, each with their own advantages and disadvantages. This guide primarily discusses occupancy measurement derived from people counters, but other methods are described briefly, with key points, for completeness:

• Wi-Fi Tracking

Any device with Wi-Fi enabled will be periodically sending out a Wi-Fi signal in order to discover and join local Wi-Fi networks. With enough Wi-Fi access points installed in a location, this signal can be detected, triangulated and tracked, and retailers and event managers will often provide ‘free Wi-Fi’ as an enabler for this purpose.

Some smart phones will actively combat this method of tracking by changing their MAC address periodically, and using different MAC addresses on each network.

Often used in conjunction with an opt-in phone app.

Only works if Wi-Fi is enabled on a device that is being carried. Therefore, this is usually a ‘sample’ technology only.

• Bluetooth Proximity Detectors

Any device with Bluetooth enabled will periodically send out signals to other Bluetooth devices and by installing detectors at strategic points those signals can be identified. With enough sensors, a person’s position can be roughly triangulated and their movement through an area determined.

Some smart phones will actively combat this method of tracking by changing their Bluetooth address details consistently.

A single person will often carry more than one Bluetooth enabled device.

The method of determining and tracking a Bluetooth address is potentially against the Bluetooth usage policy.

This method only works if Bluetooth is enabled, and is therefore a ‘sample’ only.

• Mobile Phone Tracking

Not to be confused with Bluetooth and Wi-Fi tracking (see above), tracking a mobile phone usually involves installing an app and consenting to have your location details used, usually in exchange for something free or at a discount, hence this is often used by retail chains and at special events.

Requires opt-in, therefore this is a ‘sample’ only technology.

• CCTV Crowd Analysis

Crowd analysis uses different techniques to estimate the number of pedestrians in an area. These systems are usually CCTV based, which view the area in question and calculate the occupancy based on the density of the people that it sees.

These require a lot of testing and configuration, and when configured correctly can potentially give a very consistent (but estimated) occupancy value.

• Dwell Monitoring

Dwell monitoring is similar to crowd analysis but uses multiple detectors positioned directly above the area of interest usually positioned in multiple rows to form one large field of view. The detectors can then total the number of people that they can ‘see’ (or detect) within their combined field of views.

Dependent on the technology employed can give an extremely high accuracy count.

Because the detectors are counting what they see, there is no occupancy build up that can occur with counting at the entrances and exits (see next section).

Due to the large number of devices required to fully cover an area are usually cost prohibitive.

Aligning and configuring multiple devices to form one large field of view can be setup intensive.

• People Counters

Using automatic people counting devices at strategic Entrances and Exits to count IN and OUT of an area. The area needs to be physically enclosed otherwise the number of devices required can get prohibitively expensive.

Using automatic People Counters is the most common method of occupancy analysis due to the cost to accuracy ratio and is the main discussion point of this guide.