Water Stress Index Detection Using a Low-Cost Infrared Sensor and Excess Green Image Processing

• Published in: Sensors (Basel, Switzerland) Switzerland), 2023-01, Vol.23 (3), p.1318
• Main Authors: Paulo, Rodrigo Leme de, Garcia, Angel Pontin, Umezu, Claudio Kiyoshi, Camargo, Antonio Pires de, Soares, Fabrício Theodoro, Albiero, Daniel
• Format: Article
• Language: English
• Subjects: Crops; Digital cameras; Evapotranspiration; Experiments; Humidity; Image processing; Image segmentation; infra-red sensor; Infrared detectors; Infrared imagery; Irrigation; Leaves; Low cost; Measurement; Monitoring; non-water-stressed baseline; Plant growth; precision irrigation; Sensors; soil moisture; Temperature; Thermal imaging; Thermal mapping; Thermal properties; water stress; Water use
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s23031318

Precision Irrigation (PI) is a promising technique for monitoring and controlling water use that allows for meeting crop water requirements based on site-specific data. However, implementing the PI needs precise data on water evapotranspiration. The detection and monitoring of crop water stress can be achieved by several methods, one of the most interesting being the use of infra-red (IR) thermometry combined with the estimate of the Crop Water Stress Index (CWSI). However, conventional IR equipment is expensive, so the objective of this paper is to present the development of a new low-cost water stress detection system using TL indices obtained by crossing the responses of infrared sensors with image processing. The results demonstrated that it is possible to use low-cost IR sensors with a directional Field of Vision (FoV) to measure plant temperature, generate thermal maps, and identify water stress conditions. The Leaf Temperature Maps, generated by the IR sensor readings of the plant segmentation in the RGB image, were validated by thermal images. Furthermore, the estimated CWSI is consistent with the literature results.