Quantitative Estimation of Wheat Phenotyping Traits Using Ground and Aerial Imagery

Abstract

Abstract:This study evaluates an aerial and ground imaging platform for assessment of canopy development in a wheat field. The dependence of two canopy traits, height and vigour, on fertilizer treatment was observed in a field trial comprised of ten varieties of spring wheat. A custom-built mobile ground platform (MGP) and an unmanned aerial vehicle (UAV) were deployed at the experimental site for standard red, green and blue (RGB) image collection on five occasions. Meanwhile, reference field measurements of canopy height and vigour were manually recorded during the growing season. Canopy level estimates of height and vigour for each variety and treatment were computed by image analysis. The agreement between estimates from each platform and reference measurements was statistically analysed. Estimates of canopy height derived from MGP imagery were more accurate (RMSE = 3.95 cm, R 2 = 0.94) than estimates derived from UAV imagery (RMSE = 6.64 cm, R 2 = 0.85). In contrast, vigour was better estimated using the UAV imagery (RMSE = 0.057, R 2 = 0.57), compared to MGP imagery (RMSE = 0.063, R 2 = 0.42), albeit with a significant fixed and proportional bias. The ability of the platforms to capture differential development of traits as a function of fertilizer treatment was also investigated. Both imaging methodologies observed a higher median canopy height of treated plots compared with untreated plots throughout the season, and a greater median vigour of treated plots compared with untreated plots exhibited in the early growth stages. While the UAV imaging provides a high-throughput method for canopy-level trait determination, the MGP imaging captures subtle canopy structures, potentially useful for fine-grained analyses of plants.

Editorial for the Special Issue “Estimation of Crop Phenotyping Traits using Unmanned Ground Vehicle and Unmanned Aerial Vehicle Imagery”

“…For ground platform, ground fixed scanning system [15,22,30,35], handheld-based field measuring [11,14,16,32], mobile ground platform (MGP) [14,20], and lifting hoist-based elevated platform [12,36] were reported for different crops types ( Figure 2). These platforms were easy-to-use with low cost, but data acquisition was semi-automatic.…”

“…This is clearly far more efficient compared to traditional manual measurement. Khan et al [20] also compared the estimating accuracy based on mobile ground platform (MGP) and UAV platform, and showed that the estimated canopy height derived from MGP imagery were better than UAV imagery, while the opposite results were obtained regarding the estimating of canopy vigor.…”

High Throughput Phenotyping of Physiological Growth Dynamics From Uas-Based 3d Modeling in Soybean

“…Plant height is a crucial variable connected to stability, yield potential and lodging resistance. This variable has been assessed by UAS as a Structure from Motion (SfM), obtaining high correlations with ground reference measurements for barley (Bendig et al, 2014), wheat (Khan et al,2018), poppy (Iqbal et al, 2017) and sorghum (Hu et al, 2018). In this research, senseFly eBee was chosen as a UAS, providing great flexibility and speed to accomplish mapping at high spatial and temporal resolution using an onboard Canon G9X compact digital camera, working in the visible spectrum (Red-Green-Blue).The images are processed through a fully automatic photogrammetric pipeline by the computation of the view of each image and, subsequently, the generation of a dense and scaled 3D model of the crop.…”

Erratum: Khan, Z., et al. Quantitative Estimation of Wheat Phenotyping Traits Using Ground and Aerial Imagery. Remote Sens. 2018, 10, 950

“…After publication of the research paper [1], the Remote Sensing editorial office noticed errors and wish to make the following corrections. In Equation 1, "vigourmGRVI" should be changed to "vigour~GRVI".…”

“…The changes do not affect the scientific results. The original manuscript [1] will be updated and will remain online on the article webpage, with a reference to this Erratum.…”