{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,10]],"date-time":"2026-07-10T12:17:43Z","timestamp":1783685863206,"version":"3.55.0"},"reference-count":53,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2026,7,10]],"date-time":"2026-07-10T00:00:00Z","timestamp":1783641600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000199","name":"U.S. Department of Agriculture","doi-asserted-by":"publisher","award":["58-6066-4-032"],"award-info":[{"award-number":["58-6066-4-032"]}],"id":[{"id":"10.13039\/100000199","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Infrared (IR) thermometry is essential for non-contact surface temperature monitoring in precision agriculture, but conventional single-pixel devices exhibit distance-dependent measurement errors that hinder field deployment. Most existing solutions require either fixed-geometry installations, post-processing corrections, or expensive thermal imaging systems with computational overhead. This paper presents the design, development, and evaluation of an IR thermometer measurement system that implements a lightweight signal processing algorithm for distance compensation. The instrumentation module integrates the thermometer\u2019s temperature signal with ultrasonic distance measurements and employs a distance-bias lookup table (LUT) calibrated at regulated setpoints. Real-time signal conditioning through bilinear interpolation generates corrected temperature outputs. Under controlled reference-target conditions, system evaluation across 5\u2013200 cm shows that uncompensated errors reach approximately \u22125 \u00b0C at 200 cm, whereas the proposed signal processing reduces the distance-dependent residual RMSE to below 0.20 \u00b0C over the tested range. The instrument also preserves short-term repeatability, with standard deviations between 0.08 \u00b0C and 0.12 \u00b0C across stand-off distances from 20 to 200 cm. By delivering distance-invariant measurements through external signal processing, the system is designed to support flexible, height-independent deployment of single-pixel IR thermometry for precision agriculture applications such as canopy temperature monitoring. A preliminary field measurement on a live tree canopy under one overcast condition provides initial evidence that the distance-dependent drift can be reduced outdoors, with the compensated output remaining within 0.7 \u00b0C of an external handheld reference across the 5\u2013200 cm range; comprehensive multi-condition field validation remains necessary in future work.<\/jats:p>","DOI":"10.3390\/s26144380","type":"journal-article","created":{"date-parts":[[2026,7,10]],"date-time":"2026-07-10T11:43:34Z","timestamp":1783683814000},"page":"4380","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Design of a Distance-Compensated Infrared Thermometer for Canopy Temperature Monitoring"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9137-2843","authenticated-orcid":false,"given":"Liem H. T.","family":"Nguyen","sequence":"first","affiliation":[{"name":"McComish Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, SD 57007, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Manu","family":"Chilukuri","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, University of Texas at Arlington, Arlington, TX 76019, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5111-5818","authenticated-orcid":false,"given":"Christopher D.","family":"Delhom","sequence":"additional","affiliation":[{"name":"National Center for Alluvial Aquifer Research, USDA Agricultural Research Service, Stoneville, MS 38776, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8782-6953","authenticated-orcid":false,"given":"Prasanna","family":"Gowda","sequence":"additional","affiliation":[{"name":"Smart Agriculture Research Center, University of Texas at Arlington, Arlington, TX 76019, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sungyong","family":"Jung","sequence":"additional","affiliation":[{"name":"McComish Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, SD 57007, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8190-0016","authenticated-orcid":false,"given":"Hyusim","family":"Park","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, University of North Texas, Denton, TX 76203, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"223","DOI":"10.1007\/s00271-007-0088-6","article-title":"ET mapping for agricultural water management: Present status and challenges","volume":"26","author":"Gowda","year":"2008","journal-title":"Irrig. 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