People counting glossary

Glossary of People Counting

Dictionary of terms used to describe people counting, queue management, passenger counting and footfall systems. Any questions get in touch.

Accuracy
How closely the measured people counts match the actual number of people entering and leaving. The best performing systems achieve 98% accuracy.
APC
APC stands for automatic passenger counting.
Average Shopping Time
Average Shopping Time – the length of time a person stays in a store.
Beam Counter
See Infra-Red Beam Systems
Conversion Rate
The number of people who make a purchase divided by the number of people who enter the store. If 100 people visit a store, and 5 of them buy something, the conversion rate is 5%.
Counting Zone
The area through which people must pass to be counted.
Diagonal Split
There are times when two people side-by-side may at first look like one person. Diagonal Split watches for this “one” person splitting into two. This happens, for example, when people enter through narrow doors before spreading out when more space is available.
Directional Counting
Records in and out counts: video and thermal counters do this automatically. Some infra-red beam systems rely on you dividing the count by two, although the more expensive beam counters are directional.
Dwell Time
The length of time a person stays in one area or pauses at a display.
Epoch
Count totals are saved at regular intervals: every 5 minutes or every hour say. This interval is called an epoch.
Footfall
The number of people entering an area, shop or building in a given time.
Freeze Time
A video counting system detects people moving through a counting zone. It may be, though, that a person enters the counting zone and then stands still. If they stand still for long enough, the system will consider them to be part of the background. The length of time a person can stand still and yet be counted in called the Freeze Time.
Infra-red beam systems
A sensor sends a beam to a reflector on the the opposite side of the doorway. As someone passes through the beam breaks and a person is counted. Accuracy tends to decrease with wide or busy entrances. If two people cross a beam together, for instance, only one count will be recorded. Direct sunlight onto the beam will also affect the system.These were in demand some years ago – now higher accuracy and more comprehensive information is generally demanded. More…
KPI
Key performance indicators, like sales conversion or average shopping time.

Minimum Separation
When a person first enters the counting zone, it may be that two parts of a person enter with a gap between them. For example a person carrying a briefcase might enter first by the case and then with an opposite foot or hand. To prevent this causing two separate people being “seeded”, you can specify a Minimum Separation number of pixels. (Seeding is the first sign of a person.)
Retail Sensing
Manufacturer of advanced video people counting systems and provider of business intelligence.
POS
Point-of-Sale. The place where a customer completes a transaction, such as a checkout counter. Integrating point-of-sale data with people counts allows conversion rate and other parameters to be calculated.
Retail Analytics
Studying past data to improve decision making and test assumptions. Includes indicators such as conversion rate, average shopping time, number of items per transaction and average spend.
Seeding
The system’s first sight of a person.
Tally Counter
Handheld tally counterHand-held tally counters are the least sophisticated of solutions. A person stands clicking the tally counter whenever anyone passes through the entrance. Tally counters were once used in nightclubs and bars to monitor occupancy, but are now being replaced by automatic counting systems.
Thermal Sensors
Positioned above an entrance, they detect people’s body heat. Quoted accuracies are between 96 and 98%. Accuracy, though, can be affected by the ambient temperature within the counting area being above or below a certain value. Low ceilings can also reduce the accuracy.
Tailgating (Mid Split)
When two people are following one another closely it is sometimes not possible to see the gap between them. This may be because the gap is bridged by shadows or perhaps a swinging arm or leg.Tailgating is more likely when the camera is low. A system like Video Turnstile can split people even when there is no clear gap, by simply altering the tailgating or, as it is sometimes known, the mid split setting.
Threshold
This is the value against which brightness changes in the picture are compared to detect moving people.Decreasing it will make the system more sensitive and may enable the detection of hard-to-see people. Increasing it will tend to remove any shadows and reflections which surround people. This makes it easier to see the gaps between people. On systems like Video Turnstile you can alter the threshold to suit your location.
Typical Width and Area
We define the expected size and shape of a person by two parameters: Typical Width and Typical Area. These are both measured in pixels. The system compares each person with the expected shape and allocates them a score. When people walk so closely together that it is difficult to tell them apart, these parameters help decide whether to count them as two people.
Video People Counters
Where counting units analyse CCTV pictures and identify people crossing a counting zone.
Video Turnstile
Intelligent video recognition units which count people.
Walking Line
The path someone might take through the counting zone.

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