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materials. As the largest organelle in the cell, the vacuole maintains turgor pressure within the plant cell and provides structure and support for the growing cell.
Validation (internal and external validation) Quantitative assessment of the
accuracy and precision of a measurement, model output, or model assessment.
Internal validation: based on withholding test samples repeatedly from the calibration process (e.g., through permutation, n-fold cross- validation, leave-oneout cross-validation) to predict the data withheld (validation is not independent).
External or independent validation: model assessment based on samples that
were never part of the modeling process (e.g., samples split from the population
or samples collected independently).
Validation pixels Pixels not used during the training phase of a supervised classifier or prediction model that are later used to assess the accuracy of the classifier
or prediction.
Variogram Function or plot describing the degree of spatial dependence or patterns of variation with distance. See also semivariogram.
Vector normalization Standardizing a vector to unit length, which changes the
magnitude but not the direction; a useful transformation for spectral reflectance
data from plants when the magnitude of reflectance varies among samples (see
also mean normalization).
Vegetation Plants; plants aggregated in space without reference to individual
species.
Vegetation structure Constitutes the three-dimensional vertical and horizontal
components of vegetation.
Voxel Unit of space formed by using grids to subdivide a 3-D space. While a
pixel includes x- and y-coordinates in two-dimensional space, a voxel also has a
z-coordinate. Most commonly for vegetation studies, a voxel provides characterization of the vertical distribution of plant components within a pixel, e.g., leaf
area index by height. In the context of imaging spectroscopy, a voxel is an image
pixel in coordinate space with spectral bands as the z-dimension.
Water content The amount of water in a tissue, organ, or organism, typically
expressed as the mass of unbound liquid water per unit area (content) or unit
fresh or dry weight (usually termed concentration). In remote sensing, water content is often expressed as equivalent water thickness (thickness of water, assuming all water is present as a single layer).
Wave band See band.
Wavelength range The spectral interval sampled by an instrument or covered by
a spectrum.
Wavelet transform A linear transformation of a continuous function of one variable into a continuous function of two variables, translation and scale, which are
often used to remove noise in digital image processing, for image compression,
or to identify the resolution important to variation in a signal.
Waveform decomposition Methods used to derive statistical parameters of full
waveform light detection and ranging (LiDAR) signals for characterizing vegetation three-dimensional structure and complexity.
Glossary
materials. As the largest organelle in the cell, the vacuole maintains turgor pressure within the plant cell and provides structure and support for the growing cell.
Validation (internal and external validation) Quantitative assessment of the
accuracy and precision of a measurement, model output, or model assessment.
Internal validation: based on withholding test samples repeatedly from the calibration process (e.g., through permutation, n-fold cross- validation, leave-oneout cross-validation) to predict the data withheld (validation is not independent).
External or independent validation: model assessment based on samples that
were never part of the modeling process (e.g., samples split from the population
or samples collected independently).
Validation pixels Pixels not used during the training phase of a supervised classifier or prediction model that are later used to assess the accuracy of the classifier
or prediction.
Variogram Function or plot describing the degree of spatial dependence or patterns of variation with distance. See also semivariogram.
Vector normalization Standardizing a vector to unit length, which changes the
magnitude but not the direction; a useful transformation for spectral reflectance
data from plants when the magnitude of reflectance varies among samples (see
also mean normalization).
Vegetation Plants; plants aggregated in space without reference to individual
species.
Vegetation structure Constitutes the three-dimensional vertical and horizontal
components of vegetation.
Voxel Unit of space formed by using grids to subdivide a 3-D space. While a
pixel includes x- and y-coordinates in two-dimensional space, a voxel also has a
z-coordinate. Most commonly for vegetation studies, a voxel provides characterization of the vertical distribution of plant components within a pixel, e.g., leaf
area index by height. In the context of imaging spectroscopy, a voxel is an image
pixel in coordinate space with spectral bands as the z-dimension.
Water content The amount of water in a tissue, organ, or organism, typically
expressed as the mass of unbound liquid water per unit area (content) or unit
fresh or dry weight (usually termed concentration). In remote sensing, water content is often expressed as equivalent water thickness (thickness of water, assuming all water is present as a single layer).
Wave band See band.
Wavelength range The spectral interval sampled by an instrument or covered by
a spectrum.
Wavelet transform A linear transformation of a continuous function of one variable into a continuous function of two variables, translation and scale, which are
often used to remove noise in digital image processing, for image compression,
or to identify the resolution important to variation in a signal.
Waveform decomposition Methods used to derive statistical parameters of full
waveform light detection and ranging (LiDAR) signals for characterizing vegetation three-dimensional structure and complexity.
Glossary