{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,4]],"date-time":"2026-03-04T00:16:09Z","timestamp":1772583369980,"version":"3.50.1"},"reference-count":43,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2022,1,5]],"date-time":"2022-01-05T00:00:00Z","timestamp":1641340800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003093","name":"Ministry of Higher Education, Malaysia","doi-asserted-by":"publisher","award":["TRGS\/1\/2018\/UNIMAP\/02\/4\/3"],"award-info":[{"award-number":["TRGS\/1\/2018\/UNIMAP\/02\/4\/3"]}],"id":[{"id":"10.13039\/501100003093","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The moisture content of stored rice is dependent on the surrounding and environmental factors which in turn affect the quality and economic value of the grains. Therefore, the moisture content of grains needs to be measured frequently to ensure that optimum conditions that preserve their quality are maintained. The current state of the art for moisture measurement of rice in a silo is based on grab sampling or relies on single rod sensors placed randomly into the grain. The sensors that are currently used are very localized and are, therefore, unable to provide continuous measurement of the moisture distribution in the silo. To the authors\u2019 knowledge, there is no commercially available 3D volumetric measurement system for rice moisture content in a silo. Hence, this paper presents results of work carried out using low-cost wireless devices that can be placed around the silo to measure changes in the moisture content of rice. This paper proposes a novel technique based on radio frequency tomographic imaging using low-cost wireless devices and regression-based machine learning to provide contactless non-destructive 3D volumetric moisture content distribution in stored rice grain. This proposed technique can detect multiple levels of localized moisture distributions in the silo with accuracies greater than or equal to 83.7%, depending on the size and shape of the sample under test. Unlike other approaches proposed in open literature or employed in the sector, the proposed system can be deployed to provide continuous monitoring of the moisture distribution in silos.<\/jats:p>","DOI":"10.3390\/s22010405","type":"journal-article","created":{"date-parts":[[2022,1,9]],"date-time":"2022-01-09T23:08:26Z","timestamp":1641769706000},"page":"405","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Inline 3D Volumetric Measurement of Moisture Content in Rice Using Regression-Based ML of RF Tomographic Imaging"],"prefix":"10.3390","volume":"22","author":[{"given":"Abd Alazeez","family":"Almaleeh","sequence":"first","affiliation":[{"name":"Faculty of Electrical Engineering Technology, Universiti Malaysia Perlis (UniMAP), Arau 02600, Malaysia"},{"name":"Advanced Sensor Technology, Centre of Excellence (CEASTech), Universiti Malaysia Perlis (UniMAP), Arau 02600, Malaysia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7108-215X","authenticated-orcid":false,"given":"Ammar","family":"Zakaria","sequence":"additional","affiliation":[{"name":"Faculty of Electrical Engineering Technology, Universiti Malaysia Perlis (UniMAP), Arau 02600, Malaysia"},{"name":"Advanced Sensor Technology, Centre of Excellence (CEASTech), Universiti Malaysia Perlis (UniMAP), Arau 02600, Malaysia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2547-3934","authenticated-orcid":false,"given":"Latifah Munirah","family":"Kamarudin","sequence":"additional","affiliation":[{"name":"Advanced Sensor Technology, Centre of Excellence (CEASTech), Universiti Malaysia Perlis (UniMAP), Arau 02600, Malaysia"},{"name":"Faculty of Electronic Engineering Technology, Universiti Malaysia Perlis (UniMAP), Arau 02600, Malaysia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0933-5566","authenticated-orcid":false,"given":"Mohd Hafiz Fazalul","family":"Rahiman","sequence":"additional","affiliation":[{"name":"Faculty of Electrical Engineering Technology, Universiti Malaysia Perlis (UniMAP), Arau 02600, Malaysia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1125-1978","authenticated-orcid":false,"given":"David Lorater","family":"Ndzi","sequence":"additional","affiliation":[{"name":"School of Computing, Engineering and Physical Sciences, University of the West of Scotland, Paisley PA1 2BE, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ismahadi","family":"Ismail","sequence":"additional","affiliation":[{"name":"Space Science System, Sdn. Bhd., No. 17A, Tingkat 1, Jalan SPU 2, Saujana Business Park, Bandar Saujana Putra, Jenjarom 42600, Malaysia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,1,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1007\/s12571-014-0338-4","article-title":"Rodent outbreaks and rice pre-harvest losses in Southeast Asia","volume":"6","author":"John","year":"2014","journal-title":"Food Sec."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"104","DOI":"10.17221\/1000-RAE","article-title":"Dielectric properties of agricultural products and some applications","volume":"54","author":"Nelson","year":"2008","journal-title":"Res. Agric. Eng."},{"key":"ref_3","first-page":"349","article-title":"Use of High-Frequency Currents for Grain Drying","volume":"4","author":"Knipper","year":"1959","journal-title":"J. Agric. Eng. 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