Search results for "Hemispherical photography"

showing 4 items of 4 documents

Potential of Automated Digital Hemispherical Photography and Wireless Quantum Sensors for Routine Canopy Monitoring and Satellite Product Validation

2021

To better characterize the temporal dynamics of vegetation biophysical variables, a variety of automated in situ measurement techniques have been developed in recent years. In this study, we investigated automated digital hemispherical photography (DHP) and wireless quantum sensors, which were installed at two sites under the Copernicus Ground Based Observations for Validation (GBOV) project. Daily estimates of plant area index (PAI) and the fraction of absorbed photosynthetically active radiation (FAPAR) were obtained, which realistically described expected vegetation dynamics. Good correspondence with manual DHP and LAI-2000 data (RMSE = 0.39 to 0.90 for PAI, RMSE = 0.07 for FAPAR) provid…

010504 meteorology & atmospheric sciencesMean squared errorHemispherical photographyPhotographyQuantum sensor0211 other engineering and technologies02 engineering and technologyVegetation01 natural sciencesPhotosynthetically active radiationEnvironmental scienceSatelliteWireless sensor network021101 geological & geomatics engineering0105 earth and related environmental sciencesRemote sensing2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS
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Multitemporal Monitoring of Plant Area Index in the Valencia Rice District with PocketLAI

2016

Leaf area index (LAI) is a key biophysical parameter used to determine foliage cover and crop growth in environmental studies in order to assess crop yield. Frequently, plant canopy analyzers (LAI-2000) and digital cameras for hemispherical photography (DHP) are used for indirect effective plant area index (PAI(eff)) estimates. Nevertheless, these instruments are expensive and have the disadvantages of low portability and maintenance. Recently, a smartphone app called PocketLAI was presented and tested for acquiring PAI(eff) measurements. It was used during an entire rice season for indirect PAI(eff) estimations and for deriving reference high-resolution PAI(eff) maps. Ground PAI(eff) value…

Chlorophyll contenteffective plant area index (PAI(eff))010504 meteorology & atmospheric sciencesHemispherical photographyeffective plant area index (PAIeff)Science0211 other engineering and technologiesPocketLAIPlant area index02 engineering and technologyrice; effective plant area index (PAI<sub><i>eff</i></sub>); PocketLAI; smartphone; high-resolution mapsmartphonehigh-resolution map01 natural sciencesparasitic diseasesLeaf area index021101 geological & geomatics engineering0105 earth and related environmental sciencesRemote sensing2. Zero hungerPhenologyCrop yieldriceQCiències de la terrafood and beverages15. Life on landSmartphone appGeneral Earth and Planetary SciencesEnvironmental scienceSatelliteRemote Sensing
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Accuracy assessment of fraction of vegetation cover and leaf area index estimates from pragmatic methods in a cropland area

2009

The fraction of vegetation cover (FVC) and the leaf area index (LAI) are important parameters for many agronomic, ecological and meteorological applications. Several in-situ and remote sensing techniques for estimating FVC and LAI have been developed in recent years. In this paper, the uncertainty of in-situ FVC and LAI measurements was evaluated by comparing estimates from LAI-2000 and digital hemispherical photography (DHP). The accuracy achieved with a spectral mixture analysis algorithm and two vegetation indices-based methods was assessed using atmospherically corrected Landsat Thematic Mapper (TM) data over the Barrax cropland area where the European Space Agency (ESA) SENtinel-2 and …

FEV1/FVC ratioMean squared errorHemispherical photographyThematic MapperGeneral Earth and Planetary SciencesEnvironmental sciencePlant coverSatellite imageryVegetationLeaf area indexRemote sensingInternational Journal of Remote Sensing
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Intercomparison of instruments for measuring leaf area index over rice

2015

Leaf area index (LAI) is a key biophysical parameter used to determine foliage cover and crop growth in environmental studies in order to assess crop yield. LAI estimates can be classified as direct or indirect methods. Direct methods are destructive, time consuming, and difficult to apply over large fields. Indirect methods are non-destructive and cost-effective due to its portability, accuracy and repeatability. In this study, we compare indirect LAI estimates acquired from two classical instruments such as LAI-2000 and digital cameras for hemispherical photography, with LAI estimates acquired with a smart app (PocketLAI) installed on a mobile smartphone. In this work it is shown that LAI…

VegetationHemispherical photographyriceCrop growthAgricultureIndexesRemote sensingCamerassmartphoneFoliage coverMeteorologyPhotographyLeaf Area Index (LAI)Environmental scienceLeaf area indexInstrumentsRemote sensing2015 IEEE International Geoscience and Remote Sensing Symposium (IGARSS)
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