Following on from our look at Device Tracking, in the second of our three part series on how to measure passenger flow through your airport with people counters, Jim Slevin looks at the various available people counting technologies:
There are a number of different technologies that are used for counting people:
- Beam Counters: These compact electronic traffic counters are located at entry points and emit and detect an infrared beam, counting each interruption caused when a person walks through the beam. They’re more accurate than a people counting clicker and are great for basic trends retail traffic counting. The units need to be mounted opposite the supplied reflector to count.
- Thermal Counters: Thermal counters accurately detect people by their body heat profile and can therefore count bi-directionally even when a number of people are passing simultaneously. The solution is ideal for general people traffic counting, measuring live occupancy, queue management and a range of security applications. They are widely used to monitor footfall in the transport, banking, retail, security and leisure industries.
- Synthetic intelligence: Synthetic intelligence uses multiple infra-red transceivers to create a count zone at ankle height. The artificial intelligence counters evaluate the features of each event to determine the correct outcome i.e. count per direction. As a person passes the count zone a pattern is generated and the system extracts the features of the pattern based on what it has learnt to make a decision on the type of event that has occurred.
- Video analytics: Algorithms can calculate the number of people in a queue area with a high degree of accuracy. Using the state of art algorithms and intelligent engines video analytics provide estimated wait times to inform passengers of the optimum route through the airport. Video analytics can also be used to detect an overcrowded environment and abnormal situation and can handle bi-directional counting.
Disadvantages of Counters:
The main issue is that accuracy is greatly reduced by the larger pedestrian flows found in airports and that queue times are derived and not measured leading to further inaccuracies. There are numerous other factors that can negatively affect beam counters, such as:
- The wider entrances typically found in airports
- Inward opening doors
- Infra-red beam counters are affected negatively when subject to direct sunlight
Most basic beam sensors are limited to non-directional counts, so they do not know if a person has entered or exited an area and they struggle to discern people walking side-by-side as the beam is broken at the same time. Such counters cannot count high volume, uninterrupted traffic and have a high propensity to be blocked by people standing in an entrance or by merchandise displays. The systems also require larger, more obtrusive design than other types of sensing technology.
Thermal counters have a lower field of view than video based systems and cannot be used with ceiling heights below 2.2 metres.
Video analytics only estimate queue times rather than giving definitive information. It also only gives number of people in an area not the travel times between key points and has a limited coverage area, but requires continuous coverage of these areas meaning a large number of cameras is required.