Assessing Optimal Flight Parameters for Generating Accurate Multispectral Orthomosaicks by UAV to Support Site-Speciﬁc Crop Management
This article describes the technical speciﬁcations and conﬁguration of a multirotor unmanned aerial vehicle (UAV) to acquire remote images using a six-band multispectral sensor. Several ﬂight missions were programmed as follows: three ﬂight altitudes (60, 80 and 100 m), two ﬂight modes (stop and cruising modes) and two ground control point (GCP) settings were considered to analyze the inﬂuence of these parameters on the spatial resolution and spectral discrimination of multispectral orthomosaicked images obtained using Pix4Dmapper. Moreover, it is also necessary to consider the area to be covered or the ﬂight duration according to any ﬂight mission programmed. The eﬀect of the combination of all these parameters on the spatial resolution and spectral discrimination of the orthomosaicks is presented. Spectral discrimination has been evaluated for a speciﬁc agronomical purpose: to use the UAV remote images for the detection of bare soil and vegetation (crop and weeds) for in-season site-speciﬁc weed management. These results show that a balance between spatial resolution and spectral discrimination is needed to optimize the mission planning and image processing to achieve every agronomic objective. In this way, users do not have to sacriﬁce ﬂying at low altitudes to cover the whole area of interest completely.
drone,ﬂight parameter,multispectral sensor,spatial resolution,spectral discrimination