Thermal imagery and spectral reflectance based system to monitor crop condition



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Texas Tech University


Remote sensing has gone a long way from being a scientist’s tool to being frequently used by local farmers for day-to-day irrigation decisions. Use of aircraft and satellite for remote sensing is expensive and does not have the ability to be site-specific. Handheld sensors are available for site-specific applications, but these sensors involve human intervention and cannot be used for continuous monitoring. This thesis focused on incorporating the design of a hand-held sensor in combination with GPS to implement a site-specific precision agricultural system that would continuously monitor crop water stress. This system evaluates crop stress by monitoring crop reflectance in infrared (660 nm) and near-infrared (810 nm) region of the reflectance spectrum and also crop canopy temperature. This system was mounted on a center pivot irrigation system at Texas Agricultural Experimentation Station at Helms farm, Halfway, TX. The reflectance and thermal data obtained from this system was used to evaluate crop stress. The system consisted of 36 Infrared Thermocouple (IRT) and 36 Near-Infrared (NIR, 810 nm) and Infrared (RED, 660 nm) color sensor mounted on the pivot. The Raw data from this sensor was collected and calibrated using algorithm written in Visual Basic 6. Also, Moran’s Vegetation Index and temperature (VIT) method was used to identify crop stress. This method was incorporated in the software design to create crop stress maps using ARCGIS 8.