Real-Time Observations of Leaf Vitality Extinction by Dynamic Speckle Imaging

Sap flow within a leaf is a critical indicator of plant vitality and health. This paper introduces an easy-to-use, non-invasive and real-time imaging method for sap microcirculation imaging. From the coherent backscattering of light on a leaf, we show that the acquisition frequency of dynamic speckl...

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Main Authors: Elise Colin, Enrique Garcia-Caurel, Karine Adeline, Aurélien Plyer, Xavier Orlik
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Photonics
Subjects:
Online Access:https://www.mdpi.com/2304-6732/11/11/1086
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author Elise Colin
Enrique Garcia-Caurel
Karine Adeline
Aurélien Plyer
Xavier Orlik
author_facet Elise Colin
Enrique Garcia-Caurel
Karine Adeline
Aurélien Plyer
Xavier Orlik
author_sort Elise Colin
collection DOAJ
description Sap flow within a leaf is a critical indicator of plant vitality and health. This paper introduces an easy-to-use, non-invasive and real-time imaging method for sap microcirculation imaging. From the coherent backscattering of light on a leaf, we show that the acquisition frequency of dynamic speckle can be linked to the microcirculation speed inside the leaf. Unlike conventional methods based on speckle contrast, which use integration times long enough to observe temporal decorrelation within a single image, our approach operates in a regime where speckle patterns appear ‘frozen’ in each frame of a given sequence. This ‘frozen’ state implies that any decorrelation of the speckle pattern within a frame is negligible. However, between successive frames, decorrelation becomes substantial, and it is this inter-frame decorrelation that enables the extraction of dynamic information. In this context, the integration time primarily influences the radiometric levels, while the frame acquisition rate emerges as the key parameter for generating activity index maps. Thus, by accessing different ranges of sap flow activity levels by varying the frame acquisition rate, we reveal, in a non-invasive way, the anatomy of the leaf’s circulatory network with unprecedented richness. We experimentally validate the ability of the method to characterize the vitality of a fig leaf in real time by observing the continuous decrease in sap circulation, first in the smaller vessels and then in the larger ones, following the cutting of the leaf over a 48 h period.
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spelling doaj-art-7cd77a734b574eb3be0bcd0c37c17e1f2025-08-20T02:05:01ZengMDPI AGPhotonics2304-67322024-11-011111108610.3390/photonics11111086Real-Time Observations of Leaf Vitality Extinction by Dynamic Speckle ImagingElise Colin0Enrique Garcia-Caurel1Karine Adeline2Aurélien Plyer3Xavier Orlik4ONERA (French Aerospace Lab), DTIS (Information Processing and Systems Department), University Paris-Saclay, 91123 Palaiseau, FranceLPICM (Laboratory of Physics of Interfaces and Thin Films), CNRS (French National Center for Scientific Research), École Polytechnique, Institut Polytechnique de Paris, 91128 Palaiseau, FranceONERA (French Aerospace Lab), DOTA (Department of Optics and Associated Techniques), University of Toulouse, 31055 Toulouse, FranceONERA (French Aerospace Lab), DTIS (Information Processing and Systems Department), University Paris-Saclay, 91123 Palaiseau, FranceONERA (French Aerospace Lab), DOTA (Department of Optics and Associated Techniques), University of Toulouse, 31055 Toulouse, FranceSap flow within a leaf is a critical indicator of plant vitality and health. This paper introduces an easy-to-use, non-invasive and real-time imaging method for sap microcirculation imaging. From the coherent backscattering of light on a leaf, we show that the acquisition frequency of dynamic speckle can be linked to the microcirculation speed inside the leaf. Unlike conventional methods based on speckle contrast, which use integration times long enough to observe temporal decorrelation within a single image, our approach operates in a regime where speckle patterns appear ‘frozen’ in each frame of a given sequence. This ‘frozen’ state implies that any decorrelation of the speckle pattern within a frame is negligible. However, between successive frames, decorrelation becomes substantial, and it is this inter-frame decorrelation that enables the extraction of dynamic information. In this context, the integration time primarily influences the radiometric levels, while the frame acquisition rate emerges as the key parameter for generating activity index maps. Thus, by accessing different ranges of sap flow activity levels by varying the frame acquisition rate, we reveal, in a non-invasive way, the anatomy of the leaf’s circulatory network with unprecedented richness. We experimentally validate the ability of the method to characterize the vitality of a fig leaf in real time by observing the continuous decrease in sap circulation, first in the smaller vessels and then in the larger ones, following the cutting of the leaf over a 48 h period.https://www.mdpi.com/2304-6732/11/11/1086microcirculationin vivo imagingcalibrationdynamic specklevascularizationLSOCI
spellingShingle Elise Colin
Enrique Garcia-Caurel
Karine Adeline
Aurélien Plyer
Xavier Orlik
Real-Time Observations of Leaf Vitality Extinction by Dynamic Speckle Imaging
Photonics
microcirculation
in vivo imaging
calibration
dynamic speckle
vascularization
LSOCI
title Real-Time Observations of Leaf Vitality Extinction by Dynamic Speckle Imaging
title_full Real-Time Observations of Leaf Vitality Extinction by Dynamic Speckle Imaging
title_fullStr Real-Time Observations of Leaf Vitality Extinction by Dynamic Speckle Imaging
title_full_unstemmed Real-Time Observations of Leaf Vitality Extinction by Dynamic Speckle Imaging
title_short Real-Time Observations of Leaf Vitality Extinction by Dynamic Speckle Imaging
title_sort real time observations of leaf vitality extinction by dynamic speckle imaging
topic microcirculation
in vivo imaging
calibration
dynamic speckle
vascularization
LSOCI
url https://www.mdpi.com/2304-6732/11/11/1086
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AT aurelienplyer realtimeobservationsofleafvitalityextinctionbydynamicspeckleimaging
AT xavierorlik realtimeobservationsofleafvitalityextinctionbydynamicspeckleimaging