Kasvin hyvinvoinnin määritys heijastusspektristä (Plant vitality determination by spectral measurement). Aario, S. Ph.D. Thesis, 2001.
abstract   bibtex   
Optimization of growing conditions in horticulture is traditionally based on environmental variable measurements in greenhouses. This work is a study of plant vitality by reflectance spectra measurement. The hypothesis of this study is that controlling the amount of light, water, nutrients, air temperature and humidity based on spectral measurements can manipulate plant vitality. The aim of the study is to examine correlation mechanisms between the vitality of cucumber (Cucumis Sativus) leaves and their reflectance spectra, and also to investigate how different measurement solutions would fit into the greenhouse environment and it’s demands. The reflectance spectra were measured from cucumber leaves with an imaging spectrograph in direct sunlight. The spectra were measured line by line, and rgb-images were constructed from the spectral measurements in order to be able to choose interesting areas from the leaves for further analysis. For evaluating the water-index and the amount of chlorophylls and carotenoids in the leaf, the ratio of two characteristic reflectances from different wavelengths were calculated for every substance. The changes in the distribution of the water-index were also examined during one measurement day, when the plants were desiccated. The results give us presumption that the plant vitality can be evaluated from their reflectance spectra. The water-index and chlorophyll concentration can be very accurately measured, but the determination of the amount of carotenoids still needs further investigation. A measurement device that works point by point thru the plant row would be the best solution if the outside lightning conditions do not need to be known in the analysis. Point by point measurement need to be used for long enough measuring line, so that the variations between the pixels can be analyzed and the leaves and the background can be separated. Because the outside radiation changes during the spectral measurements, there is some variation in the results. Analysis methods still need to be developed in further studies.
@phdthesis{
 title = {Kasvin hyvinvoinnin määritys heijastusspektristä (Plant vitality determination by spectral measurement).},
 type = {phdthesis},
 year = {2001},
 id = {94f8be64-4477-3b9c-895e-d8d5a592be3c},
 created = {2019-11-19T16:29:01.408Z},
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 last_modified = {2019-11-19T16:32:19.842Z},
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 citation_key = {mvg:434},
 source_type = {mastersthesis},
 notes = {M.Sc. thesis,<br/>Faculty of Science, University of Oulu, Finland, 63 p.},
 folder_uuids = {8292f5ec-1c57-4113-a303-25778e695f8c},
 private_publication = {false},
 abstract = {Optimization of growing conditions in horticulture is traditionally based on
environmental variable measurements in greenhouses. This work is a study of
plant vitality by reflectance spectra measurement. The hypothesis of this study
is that controlling the amount of light, water, nutrients, air temperature and
humidity based on spectral measurements can manipulate plant vitality. The
aim of the study is to examine correlation mechanisms between the vitality of
cucumber (Cucumis Sativus) leaves and their reflectance spectra, and also to
investigate how different measurement solutions would fit into the greenhouse
environment and it’s demands.

The reflectance spectra were measured from cucumber leaves with an
imaging spectrograph in direct sunlight. The spectra were measured line by line,
and rgb-images were constructed from the spectral measurements in order to be
able to choose interesting areas from the leaves for further analysis. For
evaluating the water-index and the amount of chlorophylls and carotenoids in
the leaf, the ratio of two characteristic reflectances from different wavelengths
were calculated for every substance. The changes in the distribution of the
water-index were also examined during one measurement day, when the plants
were desiccated.

The results give us presumption that the plant vitality can be evaluated from
their reflectance spectra. The water-index and chlorophyll concentration can be
very accurately measured, but the determination of the amount of carotenoids
still needs further investigation.

A measurement device that works point by point thru the plant row would be
the best solution if the outside lightning conditions do not need to be known in
the analysis. Point by point measurement need to be used for long enough
measuring line, so that the variations between the pixels can be analyzed and
the leaves and the background can be separated. Because the outside radiation
changes during the spectral measurements, there is some variation in the
results. Analysis methods still need to be developed in further studies.},
 bibtype = {phdthesis},
 author = {Aario, S}
}

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