Table Of Contents

Util functions

The function load_ENVI_file is use by the examples to load HSI cubes that are saved in the ENVI file format. The functions corr and cov are the one defined in the Matlab Hyperspectral Toolbox.


load_ENVI_file

util.load_ENVI_file(file_name)

Load the data, the wavelength vector and the wavelength units from an ENVI file. It use the SPy (spectral) library. At ‘file_name’ give the envi header file name.

Parameters:
file_name: path string
The complete path to the file to load. Use the header file name.
Returns: tuple
data: numpy array
A (m x n x p) HSI cube.
info: dictionary
  • info[‘z plot titles’] : a list, first position is the x axis label, second position is the y axis label.
  • info[‘wavelength’] : a wavelengths list (1D python list).
  • info[‘wavelength units’] : the x axis units, ‘Unknown’ if not specified.

load_ENVI_spec_lib

util.load_ENVI_spec_lib(file_name)

Load a ENVI .sli file.

Parameters:
file_name: path string
The complete path to the library file to load.
Returns: numpy array
A (n x p) HSI cube.

corr

util.corr(M)

Compute the sample autocorrelation matrix of a 2D matrix.

Parameters:
M: numpy array
2d matrix of HSI data (N x p)
Returns: numpy array
Sample autocorrelation matrix.

cov

util.cov(M)

Compute the sample covariance matrix of a 2D matrix.

Parameters:
M: numpy array
2d matrix of HSI data (N x p)
Returns: numpy array
sample covariance matrix