A Low-Resolution IR-Array as a Doorway Occupancy Counter in a Smart Building
DOI:
https://doi.org/10.3991/ijoe.v16i06.13915Keywords:
occupancy counter, low-resolution IR, smart building, wireless sensor, Kal-man filter tracking, PIR-sensor, GridEye, Raspberrry PiAbstract
A doorway counter, which detects a person underpass at a room entry/exit, may be the most accurate type of occupancy counters used in buildings. An occupancy counter, which uses a low-resolution IR-imager and Raspberry Pi board has been constructed. The imager provides only 8 x 8 pixels initial resolution, but it has been enhanced using two-dimensional interpolation. Due to the low absolute accuracy in temperature measurements, the imager is set to measure temperature difference between a target and background. Signal-to-noise ratio is also increased using discrete two-dimensional convolution filtering. The blob detection and tracking algorithm deduces the direction of an occupant and finally increments or decrements the counter. A heat signature varies between people and depends on person’s clothing. An on-board server on Raspberry Pi distributes the data via Wi-Fi to any client device in the net. The complete system includes also wireless PIR-sensors. The low-resolution IR occupancy counter has been compared with counters based on different technologies. The benefits of a low-resolution IR-imager are privacy preservation, operation capability in total darkness, energy-efficient passive operation and a low price.
Downloads
Published
2020-05-28
How to Cite
Maaspuro, M. (2020). A Low-Resolution IR-Array as a Doorway Occupancy Counter in a Smart Building. International Journal of Online and Biomedical Engineering (iJOE), 16(06), pp. 4–18. https://doi.org/10.3991/ijoe.v16i06.13915
Issue
Section
Papers