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Building occupancy estimation based on differential pressure sensor

IP.com Disclosure Number: IPCOM000214469D
Publication Date: 2012-Jan-30
Document File: 5 page(s) / 40K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed are building occupancy sensors and methods based on differential pressure sensors that measure change in pressure as (1) a person passes on a pressure mat with embedded sealed air pockets connected to a differential pressure sensor, and (2) due to local air disturbance generated by a person passing nearby the sensor connected in a differential measurement setup. The methods allow measuring the direction and speed of motion that can not be detected with present sensors.

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Building occupancy estimation based on differential pressure sensor

Current techniques of estimating building occupancy levels are based on either: (1) an imaging system where people are counted based on image processing and recognition,


(2) infrared sensors that can sense proximity, and/or (3) acoustic sensors that pick up sound created by moving people. Due to false triggering or misreading of the signals, combinations of sensors are utilized to improve accuracy, making the process expensive and requiring complicated electronic detection circuits.

For example, in the case of an imaging system, feature recognition (including face recognition) is computationally intensive making the method expensive and raising privacy issues. Knowing the occupancy of a room is very important for lighting control, to asses the way heating/cooling is achieved, and to identify the number of occupants. For a room that has multiple doors allowing people to move in both directions, counting the total number of people in the room can be a challenge as current sensors only indicate if a person was in proximity to a sensor, without identifying direction of motion. Tracking the direction of movement in front of sensors that are mounted at entryways can asses the number of people occupying the room. Knowing the total number of people will be useful to asses the environmental conditions in conference rooms, hospitals, and other public places and to comply with legal limits in public spaces.

For better building operation, including a schedule of heating and cooling that is optimized based on building occupancy, counting the number of people in the building at every moment of time can be of significant importance. Furthermore, remote monitoring through sensor reading could be valuable to track daily activity without privacy invasion (e.g., to monitor an elderly person's activities to ensure their health and safety).

Disclosed are building occupancy sensors and methods based on differential pressure sensors that measure change in pressure as (1) a person passes on a pressure mat with embedded sealed air pockets connected to a differential pressure sensor, and (2) due to local air disturbance generated by a person passing nearby the sensor connected in a differential measurement setup. The methods allow measuring the direction and speed of motion that can not be detected with present sensors. Furthermore, the system can assess the combination of the directional information data obtained from the sensors with building layout information and the number of people in various rooms or locations.

The measurement is based on differential measurements of a transient changes in pressure in respect to a reference pressure, as activities occur nearby the sensor system. Based on the signature of the pressure change, various activities can be differentiated. The distribution of sensors in buildings can be used to track occupancy in different locations and data are combined...