scholarly journals Commercial Digital Camera to Estimate Postharvest Leaf Area Index in Vitis vinifera L. cv. Cabernet Sauvignon on a Vertical Trellis

2010 ◽  
Vol 70 (2) ◽  
pp. 315-322 ◽  
Author(s):  
Miguel Espinosa L. ◽  
Eduardo Acuña C. ◽  
Miguel Espinosa B. ◽  
Juan Barrera B.
Keyword(s):  
Vitis Vinifera ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Digital Camera ◽  
Vitis Vinifera L ◽  
Cabernet Sauvignon ◽  
Area Index

scholarly journals An automated procedure for estimating the leaf area index (LAI) of woodland ecosystems using digital imagery, MATLAB programming and its application to an examination of the relationship between remotely sensed and field measurements of LAI

2008 ◽  
Vol 35 (10) ◽  
pp. 1070 ◽  
Author(s):  
Sigfredo Fuentes ◽  
Anthony R. Palmer ◽  
Daniel Taylor ◽  
Melanie Zeppel ◽  
Rhys Whitley ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Gap Analysis ◽  
Digital Camera ◽  
Field Measurements ◽  
Accurate Estimation ◽  
Image Capture ◽  
Area Index ◽  
Modis Lai ◽  
Matlab Programming

Leaf area index (LAI) is one of the most important variables required for modelling growth and water use of forests. Functional–structural plant models use these models to represent physiological processes in 3-D tree representations. Accuracy of these models depends on accurate estimation of LAI at tree and stand scales for validation purposes. A recent method to estimate LAI from digital images (LAID) uses digital image capture and gap fraction analysis (Macfarlane et al. 2007b) of upward-looking digital photographs to capture canopy LAID (cover photography). After implementing this technique in Australian evergreen Eucalyptus woodland, we have improved the method of image analysis and replaced the time consuming manual technique with an automated procedure using a script written in MATLAB 7.4 (LAIM). Furthermore, we used this method to compare MODIS LAI values with LAID values for a range of woodlands in Australia to obtain LAI at the forest scale. Results showed that the MATLAB script developed was able to successfully automate gap analysis to obtain LAIM. Good relationships were achieved when comparing averaged LAID and LAIM (LAIM = 1.009 – 0.0066 LAID; R2 = 0.90) and at the forest scale, MODIS LAI compared well with LAID (MODIS LAI = 0.9591 LAID – 0.2371; R2 = 0.89). This comparison improved when correcting LAID with the clumping index to obtain effective LAI (MODIS LAI = 1.0296 LAIe + 0.3468; R2 = 0.91). Furthermore, the script developed incorporates a function to connect directly a digital camera, or high resolution webcam, from a laptop to obtain cover photographs and LAI analysis in real time. The later is a novel feature which is not available on commercial LAI analysis softwares for cover photography. This script is available for interested researchers.

Early regeneration conifer identification and competition cover assessment using airborne digital camera imagery

2000 ◽  
Vol 76 (6) ◽  
pp. 915-928 ◽  
Author(s):  
K. A. Haddow ◽  
D. J. King ◽  
D. A. Pouliot ◽  
D. G. Pitt ◽  
F. W. Bell
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Vegetation Cover ◽  
Early Stage ◽  
Digital Camera ◽  
Vegetation Management ◽  
Forest Vegetation ◽  
Crop Species ◽  
Area Index ◽  
Forest Vegetation Management

The potential of low cost, high-resolution airborne digital camera imagery for use in early stage forest regeneration assessment was investigated. Airborne imagery with 2.5-cm pixel size was acquired near Sault Ste. Marie, Ontario, over a forest vegetation management research site to: i) evaluate capabilities for identification and stem counting of two-year old conifer crop species under leaf-off and leaf-on conditions using classification of spectral and textural image information, and ii) develop models relating vegetation cover parameters to image spectral and texture information. Results indicate strong potential for identification and counting of conifer trees when competing vegetation cover is low or in leaf-off condition. However, systematic decreases in class separability and conifer count accuracy were observed with increasing competition. In image modelling of competition Leaf Area Index and Cover, statistically significant relations were found using primarily spectral measures. Stratification by competition species improved model fits and included texture measures in some models. Key words: airborne remote sensing, forest vegetation management, regeneration, digital cameras, leaf area index, cover, tree classification

scholarly journals Estimation of Leaf Area Index by Using a Digital Camera in Delaware Grapes Cultivated in a Plastic Greenhouse

2012 ◽  
Vol 11 (2) ◽  
pp. 251-255
Author(s):  
Yoshinari Tateishi ◽  
Haruhiko Yamamoto ◽  
Kiyoshi Iwaya ◽  
Yasushi Tuchiya ◽  
Takao Kurahashi ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Digital Camera ◽  
Area Index

scholarly journals An Empirical Protocol for Indirect Measurement of Leaf Area Index in Grape (Vitis vinifera L.)

HortScience ◽  
1993 ◽  
Vol 28 (8) ◽  
pp. 777-779 ◽  
Author(s):  
David A. Grantz ◽  
Larry E. Williams
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Canopy Structure ◽  
Indirect Measurement ◽  
Vitis Vinifera L ◽  
Indirect Methods ◽  
Area Index ◽  
Wide Row Spacing ◽  
Radiation Sensors

Leaf area development and canopy structure are important characteristics affecting yield and fruit quality of grapevines. Trellising systems and wide row spacing are common viticultural practices that violate key assumptions of currently available indirect methods of leaf area determination. We have developed a protocol for using a commercially available instrument to determine leaf area index (LAI) indirectly in a trellised vineyard. From knowledge of plant spacing, leaf area per vine can be calculated as required. A derived calibration equation resulted in a near 1:1 relationship (y = 0.00 + 1.00 X; r2 = 0.998) between actual and indirectly determined LAI over a range of LAI induced by irrigation treatments. The protocol involved covering 75% of the sensor with a manufacturer-supplied field of view delimiter and masking data from the outer three (of five) concentric radiation sensors. The protocol could form the basis for a general measurement technique, but may require local calibration.

Leaf area index and standard error of pine forests estimated with common digital camera

2013 ◽  
Vol 21 (5) ◽  
pp. 638-644 ◽  
Author(s):  
Zhang-Hua XU ◽  
Jian LIU ◽  
Kun-Yong YU ◽  
Cong-Hong GONG ◽  
Wan-Jun XIE ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Standard Error ◽  
Digital Camera ◽  
Pine Forests ◽  
Area Index

scholarly journals Estimating Paddy Rice Leaf Area Index with Fixed Point Continuous Observation of Near Infrared Reflectance Using a Calibrated Digital Camera

2011 ◽  
Vol 14 (1) ◽  
pp. 30-46 ◽  
Author(s):  
Michio Shibayama ◽  
Toshihiro Sakamoto ◽  
Eiji Takada ◽  
Akihiro Inoue ◽  
Kazuhiro Morita ◽  
...  
Keyword(s):  
Fixed Point ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Near Infrared ◽  
Digital Camera ◽  
Paddy Rice ◽  
Infrared Reflectance ◽  
Continuous Observation ◽  
Near Infrared Reflectance ◽  
Area Index

Sistemas atmosféricos em Santa Catarina no período da maturação à colheita de videira Cabernet Sauvignon

Agrometeoros ◽  
2018 ◽  
Vol 25 (2) ◽  
Author(s):  
Cristina Pandolfo ◽  
Marilene De Lima ◽  
Angelo Mendes Massignam ◽  
Aparecido Lima da Silva ◽  
Luiz Albano Hammes
Keyword(s):  
Vitis Vinifera ◽  
Vitis Vinifera L ◽  
Cabernet Sauvignon ◽  
Santa Catarina

Os sistemas atmosféricos exercem um papel significativo no clima de uma região e poucos trabalhos determinaram os impactos dos sistemas atmosféricos no de­senvolvimento e na produção de videira. Os objetivos deste trabalho foram deter­minar a frequência de ocorrência dos sistemas atmosféricos durante o período da maturação à colheita da videira (Vitis vinifera L.) var. Cabernet Sauvignon para as duas regiões produtoras de Santa Catarina em diferentes safras e determinar a as­sociação entre a ocorrência dos sistemas atmosféricos e as regiões produtoras e as safras. Os sistemas atmosféricos foram identificados durante as safras de 2005/2006 à 2008/2009. Os municípios de Água Doce e Campos Novos foram escolhidos para re­presentar a região produtora 1 e os municípios de Bom Retiro e São Joaquim para re­presentar a região produtora 2. As frequências de ocorrências dos sistemas atmosfé­ricos durante o período da maturação à colheita de videira são muito semelhantes entre as regiões, somente houve diferença na frequência de ocorrência do sistema jato subtropical entre regiões. Houve uma diferença significativa da ocorrência da frequência dos sistemas atmosféricos entre safras.

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