PGHI - Phase Gradient Heap Integration

Usage

c=pghi(s,gamma,a,M);
c=pghi(c,gamma,a,M,mask);
c=pghi(c,gamma,a,M,mask,usephase);
[c,newphase,usedmask,tgrad,fgrad] = pghi(...);

Input parameters

`s`	Initial coefficients.
`gamma`	Window "width" factor.
`a`	Hop factor.
`M`	Number of channels.
`mask`	Mask for selecting known phase.
`usephase`	Explicit known phase.

Output parameters

`c`	Coefficients with the constructed phase.
`newphase`	Just the (unwrapped) phase.
`usedmask`	Mask used for selecting coefficients with the new phase.
`tgrad`	Relative time phase derivative.
`fgrad`	Relative frequency phase derivative.

Description

pghi(s,gamma,a,M) creates complex DGT coefficients from their absolute values s using the Phase Gradient Heap Integration algorithm. s must have been obtained as:

c = dgtreal(f,g,a,M,'timeinv');
s = abs(c);

and the algorithm attempts to recover c. Parameter gamma is window g specific and it can be computed using pghi_findgamma.

pghi(c,gamma,a,M,mask) does the same as above except it reuses phase of coefficients c for which the corresponding element from mask is nonzero.

pghi(c,gamma,a,M,mask,usephase) does the same as above but the known phase usephase is passed explicitly.

This is just a wrapper around constructphasereal from LTFAT. Please see its help for more details.

References:

Z. Průša, P. Balazs, and P. L. Søndergaard. A Noniterative Method for Reconstruction of Phase from STFT Magnitude. IEEE/ACM Trans. on Audio, Speech, and Lang. Process., 25(5), May 2017. [ DOI ]

Z. Průša and P. L. Søndergaard. Real-Time Spectrogram Inversion Using Phase Gradient Heap Integration. In Proc. Int. Conf. Digital Audio Effects (DAFx-16), Sep 2016.