| Project/Area Number |
63850086
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
計測・制御工学
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| Research Institution | University of Tokyo |
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Principal Investigator |
YAMADA Norihide Univ.of Tokyo, Faculty of Eng. Research Associate, 工学部, 助手 (30182546)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUNO Torao JIRCO Inc., Instrum. Section Research Manager, 計測機器部, 主任研究員
FUJIMURA Sadao Univ.of Tokyo, Faculty of Eng. Professor, 工学部, 教授 (30010961)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥5,600,000 (Direct Cost: ¥5,600,000)
Fiscal Year 1989: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1988: ¥3,800,000 (Direct Cost: ¥3,800,000)
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| Keywords | Chlorophyll Content / Reflectance of a Leaf / Transmittance of a Leaf / Optical Model of a Leaf / Multiple Reflection |
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| Research Abstract |
In this investigation, we propose a nondestructive or optical method of measuring the chlorophyll content in a leaf after constructing a mathematical model of reflectance and transmittance of plant leaves as a function of their chlorophyll pigment content.
The model is based on the Kubelka-Munk theory, and involves the modeling of the multiple reflection of light in a leaf which is assumed to be composed of a stack of four layers. It also includes the assumption that the scattering coefficient and the absorption coefficient of the Kubelka-Munk theory can be expressed as a linear function of the pigment content of a plant leaf.
In the proposed method, the chlorophyll content is calculated from reflectances and transmittances at three bands whose center wavelengths are 880nm, 720nm and 700nm.
Experiments were performed in order to confirm the applicability of the model and the method. Reflectance and transmittance calculated with the model showed very good agreement with measured values. Furthermore, several unmeasurable constants necessary in the calculation were determined by a least squares method. We also confirmed that these results were consistent with several well known facts in the botanical field. The method proposed here showed a very small estimation error of 6.6mu g/cm^2 over the chlorophyll content range from 0 to 80mu g/cm^2 for all kinds of plants tested.
After the applicability was confirmed, we developed a hand-held instrument to measure the chlorophyll pigment content in a leaf in accordance with the proposed method. It was also confirmed by an experiment that this instrument showed a small estimation error of 7.8mu g/cm^2 over the chlorophyll content range from 0 to lOOmu g/cm^2.
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