Abstract
The workflow for estimating the temperature in agricultural fields from multiple sensors needs to be optimized upon testing each type of sensor’s actual user performance. In this sense, readily available miniaturized UAV-based thermal infrared (TIR) cameras can be combined with proximal sensors in measuring the surface temperature. Before the two types of cameras can be operationally used in the field, laboratory experiments are needed to fully understand their capabilities and all the influencing factors. We present the measurement results of laboratory experiments of UAV-borne WIRIS 2nd GEN and handheld FLIR E8-XT cameras. For these uncooled sensors, it took 30 to 60 min for the measured signal to stabilize and the sensor temperature drifted continuously. The drifting sensor temperature was strongly correlated to the measured signal. Specifically for WIRIS, the automated non-uniformity correction (NUC) contributed to extra uncertainty in measurements. Another problem was the temperature measurement dependency on various ambient environmental parameters. An increase in the measuring distance resulted in the underestimation of surface temperature, though the degree of change may also come from reflected radiation from neighboring objects, water vapor absorption, and the object size in the field of view (FOV). Wind and radiation tests suggested that these factors can contribute to the uncertainty of several Celsius degrees in measured results. Based on these indoor experiment results, we provide a list of suggestions on the potential practices for deriving accurate temperature data from radiometric miniaturized TIR cameras in actual field practices for (agro-)environmental research.
Highlights
TIRhandheld camera designed cally for on a Unmanned Aerial Vehicles (UAV), and a camera only for reference cally for the use on a UAV, and a FLIR E8-XT handheld camera only for reference meas- m for the use onurements a UAV, and
This research assessed the effects of multiple sources of influencing factors on the performance of two radiometric miniaturized thermal infrared (TIR) camera models
Concerning the influence of the cameras’ intrinsic characteristics, the laboratory experiments in a climate room suggest that the duration of the warm-up period may vary among different models
Summary
From the 1970s on, satellite-based thermal infrared (TIR) remote sensing has been applied widely to regional-scale investigations, for instance, hydrological modeling [1,2,3], mineral exploration [4,5], urban thermal environment [6], and forest fire detection [7]. In this century, the technological development in easy-to-use low-cost miniaturized TIR cameras has enabled their application on Unmanned Aerial Vehicles (UAV) in addition to proximal platforms for local-scale studies [8,9,10,11]. These indicators serve for in-field CWS monitoring together with ground measurements of crop physiological indices (e.g., soil water content, stomatal conductance (gs ), and transpiration rate (tr )) [19,20,21,22]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
