Monitoring maize canopy chlorophyll density under lodging stress based on UAV hyperspectral imagery

2022 ◽  
Vol 193 ◽  
pp. 106671
Author(s):  
Qian Sun ◽  
Xiaohe Gu ◽  
Liping Chen ◽  
Xiaobin Xu ◽  
Zhonghui Wei ◽  
...  
1999 ◽  
Author(s):  
David M. McKeown ◽  
McGlone Jr. ◽  
Ford J. C. ◽  
Cochran Stephen J. ◽  
Shufelt Steven D. ◽  
...  

2016 ◽  
Vol 13 (12) ◽  
pp. 1910-1914 ◽  
Author(s):  
Seniha Esen Yuksel ◽  
Sefa Kucuk ◽  
Paul D. Gader

2016 ◽  
Author(s):  
Eyal Agassi ◽  
Eitan Hirsch ◽  
Martin Chamberland ◽  
Marc-André Gagnon ◽  
Holger Eichstaedt

2021 ◽  
Vol 13 (15) ◽  
pp. 3024
Author(s):  
Huiqin Ma ◽  
Wenjiang Huang ◽  
Yingying Dong ◽  
Linyi Liu ◽  
Anting Guo

Fusarium head blight (FHB) is a major winter wheat disease in China. The accurate and timely detection of wheat FHB is vital to scientific field management. By combining three types of spectral features, namely, spectral bands (SBs), vegetation indices (VIs), and wavelet features (WFs), in this study, we explore the potential of using hyperspectral imagery obtained from an unmanned aerial vehicle (UAV), to detect wheat FHB. First, during the wheat filling period, two UAV-based hyperspectral images were acquired. SBs, VIs, and WFs that were sensitive to wheat FHB were extracted and optimized from the two images. Subsequently, a field-scale wheat FHB detection model was formulated, based on the optimal spectral feature combination of SBs, VIs, and WFs (SBs + VIs + WFs), using a support vector machine. Two commonly used data normalization algorithms were utilized before the construction of the model. The single WFs, and the spectral feature combination of optimal SBs and VIs (SBs + VIs), were respectively used to formulate models for comparison and testing. The results showed that the detection model based on the normalized SBs + VIs + WFs, using min–max normalization algorithm, achieved the highest R2 of 0.88 and the lowest RMSE of 2.68% among the three models. Our results suggest that UAV-based hyperspectral imaging technology is promising for the field-scale detection of wheat FHB. Combining traditional SBs and VIs with WFs can improve the detection accuracy of wheat FHB effectively.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kenneth Clarke ◽  
Andrew Hennessy ◽  
Andrew McGrath ◽  
Robert Daly ◽  
Sam Gaylard ◽  
...  

An amendment to this paper has been published and can be accessed via a link at the top of the paper.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rehman S. Eon ◽  
Charles M. Bachmann

AbstractThe advent of remote sensing from unmanned aerial systems (UAS) has opened the door to more affordable and effective methods of imaging and mapping of surface geophysical properties with many important applications in areas such as coastal zone management, ecology, agriculture, and defense. We describe a study to validate and improve soil moisture content retrieval and mapping from hyperspectral imagery collected by a UAS system. Our approach uses a recently developed model known as the multilayer radiative transfer model of soil reflectance (MARMIT). MARMIT partitions contributions due to water and the sediment surface into equivalent but separate layers and describes these layers using an equivalent slab model formalism. The model water layer thickness along with the fraction of wet surface become parameters that must be optimized in a calibration step, with extinction due to water absorption being applied in the model based on equivalent water layer thickness, while transmission and reflection coefficients follow the Fresnel formalism. In this work, we evaluate the model in both field settings, using UAS hyperspectral imagery, and laboratory settings, using hyperspectral spectra obtained with a goniometer. Sediment samples obtained from four different field sites representing disparate environmental settings comprised the laboratory analysis while field validation used hyperspectral UAS imagery and coordinated ground truth obtained on a barrier island shore during field campaigns in 2018 and 2019. Analysis of the most significant wavelengths for retrieval indicate a number of different wavelengths in the short-wave infra-red (SWIR) that provide accurate fits to measured soil moisture content in the laboratory with normalized root mean square error (NRMSE)< 0.145, while independent evaluation from sequestered test data from the hyperspectral UAS imagery obtained during the field campaign obtained an average NRMSE = 0.169 and median NRMSE = 0.152 in a bootstrap analysis.


Author(s):  
Jing Zhao ◽  
Zixuan Ba ◽  
Xianghai Cao ◽  
Jie Feng ◽  
Licheng Jiao

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