Endmembers extraction functions¶
ATGP¶
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pysptools.eea.eea.
ATGP
(data, q)¶ Automatic Target Generation Process endmembers induction algorithm
- Parameters:
- data: numpy array
- 2d matrix of HSI data ((m x n) x p)
- q: int
- Number of endmembers to be induced (positive integer > 0)
- Returns: tuple: numpy array, numpy array
- Set of induced endmembers (N x p).
- Induced endmembers indexes vector.
- References:
- A. Plaza, C.-I. Chang, “Impact of Initialization on Design of Endmember Extraction Algorithms”, Geoscience and Remote Sensing, IEEE Transactions on, vol. 44, no. 11, pgs. 3397-3407, 2006.
FIPPI¶
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pysptools.eea.eea.
FIPPI
(M, q=None, far=None, maxit=None)¶ Fast Iterative Pixel Purity Index (FIPPI) endmqbers induction algorithm.
- Parameters:
- M: numpy array
- 2d matrix of HSI data ((m x n) x p)
- q: int [default None]
- Number of endmembers to be induced, if None use HfcVd to determine the number of endmembers to induce.
- far: float [default None]
- False alarm rate(s), a parameter to HfcVd equal to 10**-5 by default.
- maxit: `int [default None]
- Maximum number of iterations. Default = 3*p.
- Returns: tuple: numpy array, numpy array
- Set of induced endmembers (N x p).
- Array of indices into the array data corresponding to the induced endmembers.
- References:
- Chang, C.-I., “A fast iterative algorithm for implementation of pixel purity index”, Geoscience and Remote Sensing Letters, IEEE, vol. 3, no. 1, pags. 63-67, 2006.
NFINDR¶
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pysptools.eea.nfindr.
NFINDR
(data, q, transform=None, maxit=None, ATGP_init=False)¶ N-FINDR endmembers induction algorithm.
- Parameters:
- data: numpy array
- Column data matrix [nvariables x nsamples].
- q: int
- Number of endmembers to be induced.
- transform: numpy array [default None]
- The transformed ‘data’ matrix by MNF (N x components). In this case the number of components must == q-1. If None, the built-in call to PCA is used to transform the data.
- maxit: int [default None]
- Maximum number of iterations. Default = 3*q.
- ATGP_init: boolean [default False]
- Use ATGP to generate the first endmembers set instead of a random selection.
- Returns: tuple: numpy array, numpy array, int
- Set of induced endmembers (N x p)
- Set of transformed induced endmembers (N x p)
- Array of indices into the array data corresponding to the induced endmembers
- The number of iterations.
- References:
- Winter, M. E., “N-FINDR: an algorithm for fast autonomous spectral end-member determination in hyperspectral data”, presented at the Imaging Spectrometry V, Denver, CO, USA, 1999, vol. 3753, pgs. 266-275.
PPI¶
-
pysptools.eea.eea.
PPI
(M, q, numSkewers, ini_skewers=None)¶ Performs the pixel purity index algorithm for endmember finding.
- Parameters:
- M: numpy array
- 2d matrix of HSI data ((m x n) x p).
- q: int
- Number of endmembers to find.
- numSkewers: int
- Number of “skewer” vectors to project data onto.
- ini_skewers: numpy array [default None]
- You can generate skewers from another source.
- Returns: numpy array
- Recovered endmembers (N x p).