ssspy.algorithm#

ssspy.algorithm provides algorithms related to source separation.

Algorithms#

ssspy.algorithm.projection_back(data_or_filter, reference=None, reference_id=0)#

Projection back technique to restore scale ambiguity.

The implementation is based on [1].

Parameters:

  • data_or_filter (numpy.ndarray) – Estimated spectrograms or demixing filters.

  • reference (numpy.ndarray, optional) – Reference spectrogram.

  • reference_id (int, optional) – Reference microphone index. Default: 0.

Return type:

ndarray

Returns:

numpy.ndarray of rescaled estimated spectrograms or demixing filters.

Examples

When you give estimated spectrograms,

>>> import numpy as np
>>> from ssspy.algorithm import projection_back

>>> n_channels, n_bins, n_frames = 2, 2049, 128
>>> n_sources = n_channels
>>> rng = np.random.default_rng(42)

>>> spectrogram_mix = \
...     rng.standard_normal((n_channels, n_bins, n_frames)) \
...     + 1j * rng.standard_normal((n_channels, n_bins, n_frames))
>>> demix_filter = \
...     rng.standard_normal((n_sources, n_channels)) \
...     + 1j * rng.standard_normal((n_sources, n_channels))

>>> spectrogram_est = demix_filter @ spectrogram_mix.transpose(1, 0, 2)

>>> # (n_bins, n_sources, n_frames) -> (n_sources, n_bins, n_frames)
>>> spectrogram_est = spectrogram_est.transpose(1, 0, 2)

>>> spectrogram_est_scaled = \
...     projection_back(spectrogram_est, reference=spectrogram_mix, reference_id=0)
>>> spectrogram_est_scaled.shape
(2, 2049, 128)

When you give demixing filters,

>>> import numpy as np
>>> from ssspy.algorithm import projection_back

>>> n_channels, n_bins, n_frames = 2, 2049, 128
>>> n_sources = n_channels
>>> rng = np.random.default_rng(42)

>>> spectrogram_mix = \
...     rng.standard_normal((n_channels, n_bins, n_frames)) \
...     + 1j * rng.standard_normal((n_channels, n_bins, n_frames))
>>> demix_filter = \
...     rng.standard_normal((n_sources, n_channels)) \
...     + 1j * rng.standard_normal((n_sources, n_channels))

>>> demix_filter_scaled = projection_back(demix_filter, reference_id=0)

>>> spectrogram_est_scaled = demix_filter_scaled @ spectrogram_mix.transpose(1, 0, 2)

>>> # (n_bins, n_sources, n_frames) -> (n_sources, n_bins, n_frames)
>>> spectrogram_est_scaled = spectrogram_est_scaled.transpose(1, 0, 2)
>>> spectrogram_est_scaled.shape
(2, 2049, 128)