Living Image 3.1

Living Image ® Software User’s Manual
Table 8.3 Spectral unmixing options
Option Description
HP Sets a high pass filter for the spectrum. Signal below the HP cut-off
frequency is forced to zero. Choose N/A to turn off the high pass
filter. Otherwise, the value represents the high pass cut-off
frequency. This constraint can help isolate components that are
physically mixed and difficult to distinguish.
LP Sets a low pass filter for the spectrum Signal above the LP cut-off
frequency is forced to zero. Choose N/A to turn off the low pass
filter. Otherwise, the value represents the cut-off frequency of the
low pass cut-off frequency. This constraint can help isolate
components that are physically mixed and difficult to distinguish.
Sort Choose this option to automatically sort the unmixed spectra in
ascending order of their center wavelength.
Force Choose this option to force the first component to non-zero
throughout the image.
Denoise by PCA Determines how much of the data will be filtered by principal
component analysis. Stronger denoising means less principal
components will be used in the data and more details will be lost.
Stronger denoising also may slow down the unmixing.
Unimod Tolerance (%) The threshold for the unimodality constraint. It is the percentage of
overshoot allowed for the second spectral peak.
PCA
Mode PCA can be performed on the original data, the correlation matrix of
the original data, or the covariance matrix of the original data.
Click to display the explained variance.
Click to display the biplot graph.
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