$A$	Coefficient vector of radiation reduction after the spatial model
$B$	A linear transformation matrix describes the spectral effects of a sensor
$D$	The evaluation index means the normalized mean distance
Dij	The normalized mean distance between the i-th and j-th classes
dk	The normalized mean distance in the k-th band with two classes
Eλ,Direct	The solar spectral direct irradiance vector
erad	Radiometric error
F	A weighting or transformation matrix
Lλ	At-sensor spectral radiance
Lλ,s	The radiation reaching the surface of the Earth
Lλ,path	Path radiation
Lλ ,1	The radiation removes the direct reflection of objects when the surface reflectance is 1
Lm,s, Ln,s	The m- and n-band values of Lλ,s
N_res	The value of SRF in the N-th band
ndark	The effects of dark-current noise
q	The NSF obtained by the feature extraction or selection algorithm based on the processing model
$\overline{S}$	The mean of the sensor-received signal vector
Tλ,atm	Atmospheric spectral transmittance vector
Vη	Atmospheric visibility
Ws	The weight matrix of Spatial Model
$W_s^{mn}$	The value of the mth row and nth column of weight matrix Ws
X	The reflectance vector of objects
Xe	The reflectance vector of the background
$\overline{Y}$	The noisy mean vector
$\overline{Z}$	The mean of the number of spectral features (NSF)
Θsdar	The value of solar zenith angle (SZA)
τλ	The atmospheric optical thickness
${\mathsf{\Sigma }}_{L_{\lambda }}$	The covariance of the at-sensor radiance
σL,mn	The value of the mth row and nth column of covariance of Lλ
σX,mn	The values of the mth row and nth column of the reflectance covariance matrix ${\mathsf{\Sigma }}_{L_{\lambda }}$ of one of classes
σe,mn	The values of the mth row and nth column of the mean reflectance covariance matrix of all backgrounds
${\mathsf{\Sigma }}_A$	The covariance of A
σA,mn	The value of the mth row and nth column of the covariance matrix ${\mathsf{\Sigma }}_A$
σ1, σ2	The standard deviations of the point spread function in the along- and across-orbit directions
${\mathsf{\Sigma }}_s$	The covariance of the sensor-received signal vector
Δλ	The SR of the spectral radiance vectors
Λpho	The covariance matrices of photon noise
Λread	The covariance matrices of read-out noise
Λquart	The covariance matrices of quantization error
Λrand	The covariance matrix of noise model
ΣY	The signal covariance vector after noise model
ΣZ	The covariance of the number of spectral features (NSF)
${\mu }_i$	The mean of NSF based on processing model
Σi	The covariance of NSF based on processing model