BeamformerSODIX¶

class
acoular.fbeamform.
BeamformerSODIX
¶ Bases:
acoular.fbeamform.BeamformerBase
SODIX, see Funke, Ein MikrofonarrayVerfahren zur Untersuchung der Schallabstrahlung von Turbofantriebwerken, 2017. and Oertwig, Advancements in the source localization method SODIX and application to short cowl engine data, 2019
Source directivity modeling in the crossspectral matrix

method
= Trait('fmin_l_bfgs_b', desc="fit method used")¶ Type of fit method to be used (‘fmin_l_bfgs_b’). These methods is implemented in the `scipy module.

max_iter
= Int(200, …¶ Maximum number of iterations, tradeoff between speed and precision; defaults to 200

pnorm
= Float(1,desc="Norm for regularization")¶ Norm to consider for the regularization defaults to L1 Norm

alpha
= Range(0.0, 1.0, 0.0, …¶ Weight factor for regularization, defaults to 0.0.

unit_mult
= Float(1e9, …¶ Unit multiplier for evaluating, e.g., nPa instead of Pa. Values are converted back before returning. Temporary conversion may be necessary to not reach machine epsilon within fitting method algorithms. Defaults to 1e9.

sodix_result
= Property( …¶ The beamforming result as squared sound pressure values at all grid point locations (readonly). Returns a (number of frequencies, number of gridpoints) array of floats.

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
thirdoctave band
n
1/noctave band
 Returns
 array of floats
The synthesized frequency band values of the beamforming result at each grid point and each microphone . Note that the frequency resolution and therefore the bandwidth represented by a single frequency line depends on the
sampling frequency
and conjugate usedFFT block size
.

calc
(ac, fr)¶ Calculates the SODIX result for the frequencies defined by
freq_data
This is an internal helper function that is automatically called when accessing the beamformer’s
sodix_result
or calling itssynthetic()
method. Parameters
 acarray of floats
This array of dimension ([number of frequencies]x[number of gridpoints]x[number of microphones]) is used as callbyreference parameter and contains the calculated
#/= unit value after calling this method.
 frarray of booleans
The entries of this [number of frequencies]sized array are either ‘True’ (if the result for this frequency has already been calculated) or ‘False’ (for the frequencies where the result has yet to be calculated). After the calculation at a certain frequency the value will be set to ‘True’
 Returns
 This method only returns values through the ac and fr parameters
