%0 Journal Article %A Su, Jinya %A Liu, Cunjia %A Hu, Xiaoping %A Xu, Xiangming %A Guo, Lei %A Chen, Wen-Hua %D 2019 %T Spatio-temporal monitoring of wheat yellow rust using UAV multispectral imagery %U https://repository.lboro.ac.uk/articles/journal_contribution/Spatio-temporal_monitoring_of_wheat_yellow_rust_using_UAV_multispectral_imagery/9926888 %2 https://repository.lboro.ac.uk/ndownloader/files/17859950 %K Multispectral image %K Spatio-temporal analysis %K Statistical dependency %K UAV remote sensing %K Yellow rust %X
This work is focused on the spatio-temporal monitoring of winter wheat inoculated with various levels of yellow rust inoculum during the entire growth season. A dedicated workflow is devised to obtain time-series five-bands (visible-infrared) aerial imageries with a multispectral camera and an Unmanned Aerial Vehicle. A number of spectral indices are drawn so that the sensitive ones can be identified by statistical dependency analysis; particularly, their discriminating capabilities are evaluated at different stages for both wheat pixel segmentation and yellow rust severity. Then the spatial-temporal changes of sensitive bands/indices are evaluated and analysed quantitatively. A validation field experiment was designed in 2017-2018 by inoculating wheat with one of the six levels of yellow rust inoculum. Five-bands RedEdge camera on-board DJI S1000 was used to capture aerial images at eight time points covering the entire growth season at an altitude of about 20 meters with a ground resolution of 1-1.5 cm/pixel. Experimental results via spatio-temporal analysis show that: (1) various bands/indices should be used for wheat segmentation at different stages; (2) no bands/indices differences are observed for yellow rust inoculated wheat plots in both incubation stage (9 days after inoculation) and early onset stage (25 days after inoculation); (3) NIR and Red are the sensitive bands for wheat yellow rust in disease stages (45 days after inoculation); and their normalized difference NDVI index provides an even higher statistical dependency; (4) bands/indices’ sensitivity to yellow rust changes over time and decreases in later Heading stage until being very low in Ripening stage (61 days after inoculation). This experimental study provides a crucial guidance for future early spatio-temporal yellow rust monitoring at farmland scales.
%I Loughborough University