Abstract

CASTELLANO CARVAJAL, Diego Andrés et al. Alternative for Indoor Occupancy Estimation Based on Image Processing on an Embedded System. Ing. Desarro. [online]. 2022, vol.40, n.1, pp.47-70.  Epub Sep 03, 2022. ISSN 0122-3461.  https://doi.org/10.14482/inde.40.01.620.427.

Indoor occupancy estimation is a process that contributes to maintaining quality standards in areas, and, nowadays, it serves as a reference to identify possible foci of infectious respiratory diseases contagion. This paper presents a tool for indoor occupancy estimation with Simple Mail Transfer Protocol notification, using a Raspberry Pi embedded board. The system is presented as an alternative to conventional occupancy estimation systems by measuring CO2 levels in the area. The method is based on image processing by applying the background subtraction technique using Python programming language. Initially, the area where the system is tested is characterized, and preprocessing, filtering, and thresholding stages are applied, as well of notification via e-mail for SMTP. The developed system is compared with a CO2 measurement system by applying a prioritization matrix comparing factors such as detection time, hit rate, and implementation costs. The proposed method presented better performance in the totality of the comparison parameters, with a prioritization of 87.972%. Basing the system in open-source software tools and high level and low-cost hardware tools allows for the system to be replicated and implemented on a large scale in controlled environments.

Keywords : Indoor occupancy; background subtraction; Gaussian smoothing; morphological aperture; thresholding; contour finding; SMTP Protocol; embedded system; open source..

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