INFODEV     ISO 9001:2008

What is the difference between overhead (vertical) people counters and horizontal counters?

There are two ways of placing sensors to count people: vertically overhead and horizontally. While the overhead method offers the highest precision, the horizontal view has its utility when one understands well the limiting conditions of operation. Our DS-10 and DE-10 sensors are examples of these two human circulation data acquisition methods.


Persons crossing the field of vision of an horizontally placed sensor will hide other people standing beside them. The denser the traffic, the more often will two or more people cross the sensor's field of view simultaneously, giving only one passage to the sensor. These extra hidden persons are invisible to the sensors.

To know the real number of persons who have passed, statistical factors will need to be applied to the data.

These factors depend on traffic type and density. Horizontal traffic measurements only give estimates of variable precision. The denser the traffic, the less accurate the estimate. Horizontal estimation does, however, provide useful traffic profiles.

The main advantage of horizontal estimation is its cost, lower than vertical overhead counting. With our products, one DEL-10 will cover a wide entrance instead of requiring a number of DS-10's and a DL-10 data logger. Moreover, installing a DEL-10 is much more cost-effective than overhand counters.

The horizontal traffic measurement is a good choice for low-density situations, when the user can be satisfied with profiles or when budget is limited.


Using overhead counting sensors has two main advantages: accuracy and stealth.

Vertical counting sensors, because they are installed above the doors, are highly accurate. Because they are "looking" at people from above, no one can be hidden by someone else. Our overhead directional sensors provide an accuracy of counting above 95% and typically reach 97 or 98%. Contrary to horizontal counting equipment, Infodev's overhead sensor data is not processed with algorithms, rebalancing or any other correction factor. In fact, our vertical counting equipment is so accurate we don't need to do anything to the data!

Aesthetically, our overhead sensors are much smaller than the DEL-10, because they do not include a mini data-logger in their case. Moreover, we can embed the counting sensors in the doorframe or ceiling, or produce casing colours that match your environment. Sensors are wired to a Data-Logger which can be hidden behind a wall or ceiling. Moreover, overhead equipment is barely noticeable to passers-by and less exposed to vandalism than horizontal equipment, which is installed waist-high.

Vertical traffic measurement is a good choice for high-density situations, when the user must have the highest accuracy possible and when aesthetics are a primary concern.