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Application of non-negative matrix factorization for studying short-term physiological changes in grapevine from canopy hyperspectral reflection
  • Staša Puškarić,
  • Mateo Sokač,
  • Ksenija Matić
Staša Puškarić
RIT Croatia

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Mateo Sokač
Aarhus Universitet
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Ksenija Matić
RIT Croatia
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Abstract

We have applied non-negative matrix factorization to a database of leaf hyperspectral reflectance and DMSO chlorophyll extract absorption measurements from grapevine canopies at seven vineyards in Dalmatia, Croatia. Extracted spectral signatures show various monthly changes in grapevine production of chlorophyll. Our signatures represent maximal absorption values within a specific colour spectrum - blue, red, near infrared, green and yellow to orange. Association of signatures and chlorophyll indices vary through time. Signature 4 is the best chlorophyll proxy. Here we show that the same amount of chlorophyll can be produced by plants using multiple internal processes or absorption of different spectrums of light. Changes in these processes can be better understood by studying extracted reflection signatures instead of just chlorophyll concentration or vegetation indices. This study shows that non-negative matrix factorization applied to hyperspectral reflectance measurements can be a powerful tool in monitoring the short-term changes in physiology of plants thus could be applied in precision viticulture. We also tested this model on canopy hyperspectral reflectance measured at 0.5 m distance from the canopy. This study shows that NMF can be a powerful tool in monitoring the seasonal grapevine changes in physiology of plants thus could be applied in precision viticulture.