Agrowing multispectral sensor – automatic counting and plants classification in a 18ha almonds orchard in Israel.

Agrowing multispectral camera – automatic counting and trees classification in an almonds orchard in Israel.

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Counting and plant vigor diagnosis from high resolution multispectral aerial images taken with the powerful Agrowing A7RIV Quad kit.

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Above are the different stages of a service aimed to map each tree according to its plant vigor (based on the NDVI index).

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Photogrammetry – geospatial datas production

As illustrated below with Agisoft Metashape, first step consist in 3D modeling the entire site and then export a multilayer orthophoto with 12 spectral channels (in accordance with the 12 bands generated natively by the A7R4 Quad for each shooting).

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Remote sensing – NDVI index calculation

Only 4 channels are useful with this use case: red, green, blue and near infrared. This for the subsequent built of a conventional RGB orthophoto (for visual comfort) and the NDVI index calculation as illustrated below from the red and near infrared channels.

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Deep learning – detection and localization

Thanks to the high resolution of this Agrowing sensor, the previously built orthophoto (GSD2cm with a 115m height flight) offer a very high level of details which perfectly reproduce the singular shape of almond trees. In this context, detection by deep learning based on color & shape can be considered.

Once the almond trees are perfectly segmented with respect to each other, a NDVI value can then be assigned locally for each tree.

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Conclusion

In addition to its 12 spectral channels dedicated to remote sensing indexes customization, the high resolution of the A7R4 Quad sensor make it possible to generate extremely well detailed NDVI maps but also to enrich them with automatic detection/counting: an unique advantage that meets perfectly to ecological issues and precision farming needs.

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Technical informations

  • Aerial images source : Agrowing
  • Data processing : Drones Imaging
  • Spatial accuracy : centimétrique.
  • Orthophoto RGB-NIR : 2cm GSD.
  • Counting : 4131 almond trees detected.
  • Camera : Agrowing A7R4 Quad
  • Covered area : 18ha
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