counted have no sensation from the counting device and their identity is not
registered (that’s left to the video surveillance and access control systems).
The thermal imaging is not affected by lighting or other conditions. Devices
are typically mounted 8 to 15 feet high.
The devices are relatively low cost and can be easily installed. Each device
contains a sensor, imaging optics, a signal processor, and some type of net-
working interface to connect to other devices or the main administration
terminal. Multiple devices can be used for larger-width door openings and can
be programmed to avoid double-counting, essentially acting as a single device.
Video imaging typically uses small cameras with an auto-iris lens and video
analytics to count and differentiate among people entering and exiting a build-
ing or space. People-counting capability as an add-on module of a video sur-
veillance system is not unusual.
Some of the actionable information that can be created from people coun-
ters includes the following:
Access Control
One of the typical issues with access control systems is “tailgating” or “piggyback-
ing.” Tailgating is when someone with a valid access card enters a building but is
immediately followed by an unauthorized person before the door closes. A people-
counting system would accurately detect “tailgaters,” helping prevent unauthorized
access, resulting in a higher level of security and less theft or vandalism.
Life Safety
Data on the number of people leaving buildings in the event of an emergency
evacuation and the number of people who had entered the building are
valuable information for first emergency responders.
Financial Metrics of Retail Stores
People-counting systems probably originated in the retail sector and large
venues (theme parks, stadiums, etc.). Retail stores can easily correlate foot traffic
into the store with the store’s business metrics, answering questions such as:
n What’s the conversion rate of foot traffic to buyers?
n What’s the average revenue per person entering the store?
n What are the seasonal traffic patterns?
n How do similar stores in different locations compare?
n How can the number of sales staff be optimized to the number and
patterns of people entering a store?80 Smart Building Systems for Architects, Owners, and Builders