People counter
From Wikipedia, the free encyclopedia
A people counter is a device, used to count the number of pedestrians walking through a portal or corridor. The device is often used at the entrance of a building so that the total number of visitors can be recorded. Many people counter devices use infrared technology to detect movement through a portal or corridor.
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[edit] Reasons for People Counting
There are many diverse reasons for counting people, the most common of which are:
[edit] Retail Intelligence
Use of people counting systems in the retail environment is necessary to calculate Conversion Rate, i.e. the proportion of an outlet's visitors that make purchases. This is the key performance indicator of a store's performance and is far superior to traditional methods, which only take account of turnover.
[edit] Planning of Staffing
Since staff requirements are often directly related to density of visitor traffic, accurate visitor counting is essential in the process of optimising staff shifts.
[edit] Planning of Service Activities
Services such as cleaning and maintenance typically must be done when traffic is at its lowest or, occasionally, at a certain level. Planning of these activities necessitates accurate people counting.
[edit] Safety, in the event of evacuation
For many locations it is essential to know how many people are inside the building at any given time, so that in the event of an evacuation they can all be accounted for. This can only be automated with the use of extremely accurate people counting systems.
[edit] Evidence of resource usage, in support of finance applications
Many public organisations are dependent of reports of visitor counts for their finance. In cases where tickets are not sold, such as museums and libraries, the only effective way to automate the counting of visitors is with a people conting system.
[edit] Technologies
Contemporary people counting systems use many different technologies, each with its own advantages and disadvantages. The main ones are listed below.
[edit] Infrared Beams
The simplest form of counter is a single, horizontal beam across an entrance which is typically linked to a small LCD display unit at the side of the doorway. Such a beam only counts a 'tick' when the beam is broken, therefore it is normal to divide the 'ticks' by two to get visitor numbers.
Vertical beams are somewhat more accurate than horizontal, with accuracies of over 90% possible of the beams are very carefully placed. Typically they do not give 'in and out' information, although some directional beams do exist.
[edit] Advantages
- Inexpensive
- Simple to fit
[edit] Disadvantages
- Inaccurate: accuracies can be as low as 50%.
- Lack of integration with other systems: often the only way to receive the data is for staff to physically note it down, which introduces a significant weak link in the system.
[edit] Computer Vision
The most recent devlopment of people counting and 'state-of-the-art' is represented by computer vision systems. These typically use either a Closed-circuit television camera or IP camera to feed a signal into either a PC or embedded device.
Some computer vision systems have integrated links to database systems and retail Point of sale systems.
[edit] Advantages
- High accuracy, sometimes over 98%
- Directional information
- Flexible in customisation
- Integration with other systems
[edit] Disadvantages
- Higher cost than beam systems
- Less simple implementation than beam systems
[edit] Thermal Imaging
Thermal Imaging systems use sensors which detect heat sources, rather than using cameras as in computer vision systems. These systems are typically implemented using embedded technology.
[edit] Advantages
- High accuracy
- Directional information
- Simple fitting
[edit] Disadvantages
- Higher cost than beam systems
- Less simple implementation than beam systems
- Not as flexible or powerful as computer vision systems
