{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,22]],"date-time":"2026-02-22T06:17:13Z","timestamp":1771741033326,"version":"3.50.1"},"reference-count":25,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2021,6,12]],"date-time":"2021-06-12T00:00:00Z","timestamp":1623456000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"FESR","award":["PRELuDE (POR FESR, 2014-2020"],"award-info":[{"award-number":["PRELuDE (POR FESR, 2014-2020"]}]},{"name":"FESR","award":["OPIS (POR FESR, 2014-2020)"],"award-info":[{"award-number":["OPIS (POR FESR, 2014-2020)"]}]},{"name":"FESR","award":["ARTeller (POR FESR, 2014-2020)"],"award-info":[{"award-number":["ARTeller (POR FESR, 2014-2020)"]}]},{"name":"FESR","award":["DigitArch (POR FESR, 2014-2020)"],"award-info":[{"award-number":["DigitArch (POR FESR, 2014-2020)"]}]},{"DOI":"10.13039\/501100003407","name":"MIUR","doi-asserted-by":"publisher","award":["Cagliari2020 project (MIUR, PON04a2 00381)"],"award-info":[{"award-number":["Cagliari2020 project (MIUR, PON04a2 00381)"]}],"id":[{"id":"10.13039\/501100003407","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>We propose a device for monitoring the number of people who are physically present inside indoor environments. The device performs local processing of infrared array sensor data detecting people\u2019s direction, which allows monitoring users\u2019 occupancy in any space of the building and also respects people privacy. The device implements a novel real-time pattern recognition algorithm for processing data sensed by a low-cost infrared (IR) array sensor. The computed information is transferred through a Z-Wave network. On-field evaluation of the algorithm has been conducted by placing the device on top of doorways in offices and laboratory rooms. To evaluate the performance of the algorithm in varying ambient temperatures, two groups of stress tests have been designed and performed. These tests established the detection limits linked to the difference between the average ambient temperature and perturbation. For an in-depth analysis of the accuracy of the algorithm, synthetic data have been generated considering temperature ranges typical of a residential environment, different human walking speeds (normal, brisk, running), and distance between the person and the sensor (1.5 m, 5 m, 7.5 m). The algorithm performed with high accuracy for routine human passage detection through a doorway, considering indoor ambient conditions of 21\u201330 \u00b0C.<\/jats:p>","DOI":"10.3390\/s21124062","type":"journal-article","created":{"date-parts":[[2021,6,14]],"date-time":"2021-06-14T22:25:46Z","timestamp":1623709546000},"page":"4062","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":34,"title":["Monitoring Indoor People Presence in Buildings Using Low-Cost Infrared Sensor Array in Doorways"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1506-423X","authenticated-orcid":false,"given":"Cristian","family":"Perra","sequence":"first","affiliation":[{"name":"Department of Electrical and Electronic Engineering, UdR CNIT, University of Cagliari, Via Marengo 2, 09123 Cagliari, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2547-0071","authenticated-orcid":false,"given":"Amit","family":"Kumar","sequence":"additional","affiliation":[{"name":"Department of Electrical and Electronic Engineering, UdR CNIT, University of Cagliari, Via Marengo 2, 09123 Cagliari, Italy"}]},{"given":"Michele","family":"Losito","sequence":"additional","affiliation":[{"name":"Department of Electrical and Electronic Engineering, UdR CNIT, University of Cagliari, Via Marengo 2, 09123 Cagliari, Italy"}]},{"given":"Paolo","family":"Pirino","sequence":"additional","affiliation":[{"name":"Department of Electrical and Electronic Engineering, UdR CNIT, University of Cagliari, Via Marengo 2, 09123 Cagliari, Italy"}]},{"given":"Milad","family":"Moradpour","sequence":"additional","affiliation":[{"name":"Department of Electrical and Electronic Engineering, UdR CNIT, University of Cagliari, Via Marengo 2, 09123 Cagliari, Italy"}]},{"given":"Gianluca","family":"Gatto","sequence":"additional","affiliation":[{"name":"Department of Electrical and Electronic Engineering, UdR CNIT, University of Cagliari, Via Marengo 2, 09123 Cagliari, Italy"}]}],"member":"1968","published-online":{"date-parts":[[2021,6,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Kubba, S. (2017). Building Information Modeling (BIM). Handbook of Green Building Design and Construction, Elsevier.","DOI":"10.1016\/B978-0-12-810433-0.00005-8"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1243","DOI":"10.1080\/15732479.2015.1110601","article-title":"Auto-generated site layout: An integrated approach to real-time sensing of temporary facilities in infrastructure projects","volume":"12","author":"Akanmu","year":"2015","journal-title":"Struct. Infrastruct. Eng."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1016\/j.inffus.2018.11.010","article-title":"Short-long term anomaly detection in wireless sensor networks based on machine learning and multi-parameterized edit distance","volume":"52","author":"Cauteruccio","year":"2019","journal-title":"Inf. Fusion"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Hayat, H., Griffiths, T., Brennan, D., Lewis, R.P., Barclay, M., Weirman, C., Philip, B., and Searle, J.R. (2019). The state-of-the-art of sensors and environmental monitoring technologies in buildings. Sensors, 19.","DOI":"10.3390\/s19173648"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"320","DOI":"10.1016\/j.is.2014.06.005","article-title":"Hybrid wireless sensor network for building energy management systems based on the 2.4 GHz and 400 MHz bands","volume":"48","author":"Kim","year":"2015","journal-title":"Inf. Syst."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"109861","DOI":"10.1016\/j.enbuild.2020.109861","article-title":"Energy-saving building system integration with a smart and low-cost sensing\/control network for sustainable and healthy living environments: Demonstration case study","volume":"214","author":"Han","year":"2020","journal-title":"Energy Build."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Yassein, M.B., Mardini, W., and Khalil, A. (2016, January 22\u201324). Smart homes automation using Z-wave protocol. Proceedings of the 2016 International Conference on Engineering & MIS (ICEMIS), Agadir, Morocco.","DOI":"10.1109\/ICEMIS.2016.7745306"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1145\/3230633","article-title":"A survey on gait recognition","volume":"51","author":"Wan","year":"2018","journal-title":"ACM Comput. Surv."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1049\/iet-bmt.2018.5063","article-title":"Robust gait recognition: A comprehensive survey","volume":"8","author":"Rida","year":"2018","journal-title":"IET Biom."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"154","DOI":"10.1109\/LSP.2015.2507200","article-title":"Human body part selection by group lasso of motion for model-free gait recognition","volume":"23","author":"Rida","year":"2015","journal-title":"IEEE Signal Process. Lett."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"375","DOI":"10.1109\/TSMC.2013.2263130","article-title":"Mobile target scenario recognition via low-cost pyroelectric sensing system: Toward a context-enhanced accurate identification","volume":"44","author":"Sun","year":"2014","journal-title":"IEEE Trans. Syst. Man Cybern. Syst."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1016\/j.infrared.2013.12.020","article-title":"A novel low-cost and small-size human tracking system with pyroelectric infrared sensor mesh network","volume":"63","author":"Yang","year":"2014","journal-title":"Infrared Phys. Technol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"428","DOI":"10.1109\/JSYST.2009.2035734","article-title":"Multiple human tracking and identification with wireless distributed pyroelectric sensor systems","volume":"3","author":"Qi","year":"2009","journal-title":"IEEE Syst. J."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Chowdhury, Z.I., Imtiaz, M.H., Azam, M.M., Sumi, M.R.A., and Nur, N.S. (2011, January 14\u201316). Design and implementation of pyroelectric infrared sensor based security system using microcontroller. Proceedings of the IEEE Technology Students\u2019 Symposium, Kharagpur, India.","DOI":"10.1109\/TECHSYM.2011.5783853"},{"key":"ref_15","unstructured":"Caicedo, D., and Pandharipande, A. (2012, January 27\u201331). Ultrasonic array sensor for indoor presence detection. Proceedings of the 20th European Signal Processing Conference (EUSIPCO), Bucharest, Romania."},{"key":"ref_16","unstructured":"Basu, C., and Rowe, A. (2015). Tracking motion and proxemics using thermal-sensor array. arXiv."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Mohammadmoradi, H., Munir, S., Gnawali, O., and Shelton, C. (2017, January 5\u20137). Measuring people-flow through doorways using easy-to-install ir array sensors. Proceedings of the 2017 13th International Conference on Distributed Computing in Sensor Systems (DCOSS), Ottawa, ON, Canada.","DOI":"10.1109\/DCOSS.2017.26"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"16","DOI":"10.4236\/jcc.2017.54002","article-title":"Indoor human detection based on thermal array sensor data and adaptive background estimation","volume":"5","author":"Trofimova","year":"2017","journal-title":"J. Comput. Commun."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Jeong, Y., Yoon, K., and Joung, K. (2014, January 18\u201320). Probabilistic method to determine human subjects for low-resolution thermal imaging sensor. Proceedings of the 2014 IEEE Sensors Applications Symposium (SAS), Queenstown, New Zealand.","DOI":"10.1109\/SAS.2014.6798925"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1016\/j.infrared.2019.01.011","article-title":"Indoor multiple human targets localization and tracking using thermopile sensor","volume":"97","author":"Qu","year":"2019","journal-title":"Infrared Phys. Technol."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Maaspuro, M. (2020). A low-resolution IR-array as a doorway occupancy counter in a smart building. Int. J. Online Biomed. Eng. (iJOE), 16.","DOI":"10.3991\/ijoe.v16i06.13915"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"325","DOI":"10.1080\/00038628.2020.1748869","article-title":"The shakedown: Developing an indoor-localization system for quantifying toilet usage in offices","volume":"63","author":"Doherty","year":"2020","journal-title":"Archit. Sci. Rev."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Spasov, G., Tsvetkov, V., and Petrova, G. (2019, January 12\u201314). Using IR array MLX90640 to build an IoT solution for ALL and security smart systems. Proceedings of the 2019 IEEE XXVIII International Scientific Conference Electronics (ET), Sozopol, Bulgaria.","DOI":"10.1109\/ET.2019.8878637"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1109\/JSEN.2019.2942320","article-title":"Dynamic fuzzy background removal for indoor human target perception based on thermopile array sensor","volume":"20","author":"Gu","year":"2019","journal-title":"IEEE Sens. J."},{"key":"ref_25","unstructured":"(2021, April 22). Panasonic High Performance Grid-EYE Sensors Reference Specification. Available online: https:\/\/na.industrial.panasonic.com\/file-download\/4108."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/12\/4062\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T06:13:46Z","timestamp":1760163226000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/12\/4062"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,6,12]]},"references-count":25,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2021,6]]}},"alternative-id":["s21124062"],"URL":"https:\/\/doi.org\/10.3390\/s21124062","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,6,12]]}}}