BeamformerMusic

class acoular.fbeamform.BeamformerMusic

Bases: BeamformerEig

Beamforming using the MUSIC algorithm.

See [7] for details.

r_diag

Boolean flag, if True, the main diagonal is removed before beamforming; for MUSIC beamforming r_diag is set to False.

r_diag_norm

Normalization factor in case of CSM diagonal removal. Defaults to 1.0 since BeamformerMusic is only well defined for full CSM.

n

assumed number of sources

integrate(sector, frange=None, num=0)

Integrates result map over a given sector.

Parameters:

sector: array of floats or :class:`~acoular.grids.Sector`

either an array, tuple or list with arguments for the ‘indices’ method of a Grid-derived class (e.g. RectGrid.indices or RectGrid3D.indices). Possible sectors would be array([xmin, ymin, xmax, ymax]) or array([x, y, radius]) or an instance of a Sector-derived class

frange: tuple or None

a tuple of (fmin,fmax) frequencies to include in the result if num*==0, or band center frequency/frequencies for which to return the results if *num>0; if None, then the frequency range is determined from the settings of the PowerSpectra.ind_low and PowerSpectra.ind_high of freq_data

numinteger

Controls the width of the frequency bands considered; defaults to 0 (single frequency line). Only considered if frange is not None.

num	frequency band width
0	single frequency line
1	octave band
3	third-octave band
n	1/n-octave band

Returns:

res or (f, res): array of floats or tuple(array of floats, array of floats)

If frange*==None or *num>0, the spectrum (all calculated frequency bands) for the integrated sector is returned as res. The dimension of this array is the number of frequencies given by freq_data and entries not computed are zero. If frange!=None and num*==0, then (f, res) is returned where *f are the (band) frequencies and the dimension of both arrays is determined from frange

sig_loss_norm()

If the diagonal of the CSM is removed one has to handle the loss of signal energy.

Done via a normalization factor.

synthetic(f, num=0)

Evaluates the beamforming result for an arbitrary frequency band.

Parameters:

f: float

Band center frequency.

numinteger

Controls the width of the frequency bands considered; defaults to 0 (single frequency line).

num	frequency band width
0	single frequency line
1	octave band
3	third-octave band
n	1/n-octave band

Returns:

array of floats

The synthesized frequency band values of the beamforming result at each grid point . Note that the frequency resolution and therefore the bandwidth represented by a single frequency line depends on the sampling frequency and used FFT block size.

na

No. of eigenvalue

digest

A uniquernal identifier for the beamformer, based on its properties. (read-only)

steer

Instance of SteeringVector or its derived classes that contains information about the steering vector. This is a private trait. Do not set this directly, use steer trait instead.

freq_data

PowerSpectra object that provides the cross spectral matrix and eigenvalues

precision

Floating point precision of property result. Corresponding to numpy dtypes. Default = 64 Bit.

cached

Boolean flag, if ‘True’ (default), the result is cached in h5 files.

h5f

hdf5 cache file

result

The beamforming result as squared sound pressure values at all grid point locations (readonly). Returns a (number of frequencies, number of gridpoints) array-like of floats. Values can only be accessed via the index operator [].