GABREASSIGNADJUST - Adjustable reassignment of a time-frequency distribution

Usage

sr = gabreassignadjust(s,pderivs,a,mu);

Description

gabreassignadjust(s,pderivs,a,mu) reassigns the values of the positive time-frequency distribution s using first and second order phase derivatives given by pderivs and parameter mu>0. The lattice is determined by the time shift a and the number of channels deduced from the size of s.

pderivs is a cell array of phase derivatives which can be obtained as follows:

pderivs = gabphasederiv({'t','f','tt','ff','tf'},...,'relative');

Please see help of gabphasederiv for description of the missing parameters.

gabreassign(s,pderivs,a,mu,despeckle) works as above, but some coeficients are removed prior to the reassignment process. More precisely a mixed phase derivative pderivs{5} is used to determine which coefficients m,n belong to sinusoidal components (such that abs(1+pderivs{5}(m,n)) is close to zero) and to impulsive components (such that abs(pderivs{5}(m,n)) is close to zero). Parameter despeckle determines a threshold on the previous quantities such that coefficients with higher associated values are set to zeros.

Algorithm

The routine uses the adjustable reassignment presented in the references.

Examples:

The following example demonstrates how to manually create a reassigned spectrogram.:

% Compute the phase derivatives
a=4; M=100;
[pderivs, c] = gabphasederiv({'t','f','tt','ff','tf'},'dgt',bat,'gauss',a,M,'relative');

% Reassignemt parameter
mu = 0.1;
% Perform the actual reassignment
sr = gabreassignadjust(abs(c).^2,pderivs,a,mu);

% Display it using plotdgt
plotdgt(sr,a,143000,50);