Spectral analysis of passion fruit cultivation using the WingQuad3
TropicFruit is a company dedicated to all kinds of tropical fruit production for commercialization. With the intent to maximize the production of passion fruit, TropicFruit hired our company to develop the technique of precision agriculture in their fruit production. This case study is about passion fruit spectral information and precision agriculture.
The objectives of this project were to generate DTM, DSM models, contour lines and generate an orthomosaic of each band of the multispectral and RGB camera.
For doing this flight we used a WingQuad3. This drone allows us to cover an area of 500 hectares with a flight autonomy of 60 minutes. Another feature is that it is easy to take off and land without a track.
The Sony A5100 camera was used to generate the RGB images. The Voigtlander lens was integrated into the camera to acquire high resolution and not distorted images. 816 images were geolocated with a median of 80731 keypoints per image. The following figure shows the view of the initial image position.
To have the perfectly georeferenced dataset and obtain topographic precision, WINGQUAD 3 VTOL used 5 control points (GCPs) with Pix4D software.
After processing the following results were obtained:
Point cloud in LAS format.
Orthomosaic with ground sample distance of 5,17 cm/pixel.
Digital Surface Model (DSM)
Digital Terrain Model (DTM)
Contour lines of 1 meter in shp format.
All the process to obtain RGB information was performed with the Pix4D software, but TropicFruit company needed the spectral information too. For this reason, the Parrot Sequoia camera was used to get RED, RED-EDGE, NIR and GREEN bands.
Using multispectral information, nutrient analysis, fertility maps, accurate plant counts, vegetation index calculation, soil temperature, asses losses, pest monitoring, and more can be achieved.
Depending on the band or combination of bands used, it is possible to achieve certain specific information about the plantations.
For example, Near (NIR) infrared spectroscopy was investigated as rapid methods for evaluating quality traits of fresh passion fruit pulp. Models to predict soluble solids content (SSC), titratable acidity (TA), glucose (GLC), fructose (FRU), sucrose (SUC) and vitamin C (ascorbid acid).
The green band is used in the green vegetation index (GVI) presents high values in objectives with a high density of green vegetation.
Usually, the RED band is used to perform chlorophyll analysis and classification of plant cover.
The Red-Edge band is strategically focused on the beginning of the portion where the reflectivity has high values due to the response of the vegetation, rooting its interest in the fact that it is in the transition zone between the minimum and maximum reflectance, being able to be useful in the measurement of the state of the vegetation.
In conclusion, the most important objective of precision agriculture is to obtain better economic, environmentally friendly and social results with cheap costs.
Modern photogrammetry Drone executed by Latitude Aerospace Solutions
Drones and Pilot Designers: Ing. Pedro Meneses, Ing. Jorge Pantoja, Ing. José Barzallo.
GCPs design, flight planning and processing photogrammetric data: Ing. Gabriela López. Ing. Pedro Meneses
Technical report: Ing. Gabriela López
GCPs Measurements and processing: Ing. Gabriela López