function tifd=friedman(tfr,hat,t,method,trace);%FRIEDMAN Instantaneous frequency density.%	TIFD = FRIEDMAN(TFR,HAT,T,METHOD,TRACE) computes the%	time-instantaneous frequency density (defined by Friedman [1])%	of a reassigned time-frequency representation.% %	TFR   : time-frequency representation, (N,M) matrix.%	HAT   : complex matrix of the reassignment vectors.%	T     : the time instant(s)	(default : (1:M)).%	METHOD: chosen representation	(default : 'tfrrsp').  %	TRACE : if nonzero, the progression of the algorithm is shown%					(default : 0).%	TIFD  : time instantaneous-frequency density. When called without %	        output arguments, FRIEDMAN runs TFRQVIEW.%%	WARNING : TIFD is not an energy distribution, but an estimated %	-------        probability distribution !%%	Example : %	 sig=fmlin(128,0.1,0.4); h=window(47,'Kaiser');%	 t=1:2:127; [tfr,rtfr,hat]=tfrrpwv(sig,t,128,h);%	 friedman(tfr,hat,t,'tfrrpwv',1); %%	See also : RIDGES.%	F. Auger, August 1994, Decembre 1995.%	Copyright (c) 1996 by CNRS (France).%%	------------------- CONFIDENTIAL PROGRAM -------------------- %	This program can not be used without the authorization of its%	author(s). For any comment or bug report, please send e-mail to %	f.auger@ieee.org %%	[1] : D. H. Friedman, "Instantaneous Frequency vs Time : An%	      Interpretation of the Phase Structure of Speech", Proc. IEEE%	      ICASSP, pp. 29.10.1-4, Tampa, 1985.	if (nargin<3), error('At least 2 parameters required'); end;[tfrrow,tfrcol]=size(tfr);[hatrow,hatcol]=size(hat);if (nargin==2), t=1:tfrcol; method='tfrrsp'; trace=0;elseif (nargin==3), method='tfrrsp'; trace=0;elseif (nargin==4), trace=0;end;[trow,tcol] = size(t);if (trow~=1), error('T must only have one row'); elseif (tfrrow~=hatrow)|(tfrcol~=hatcol), error('tfr and hat must have the same size');end;tifd=zeros(tfrrow,tfrcol);bins=0.5+(0:tfrrow-1);threshold=sum(sum(tfr))*0.5/(tfrrow*tfrcol);if trace, fprintf ('\nFriedman distribution: \n'); end;for j=1:tfrcol, if trace, disprog(j,tfrcol,10); end; indices=find(tfr(:,j)>threshold); if (length(indices)>=1),  [occurences,trash]=hist(real(hat(indices,j)),bins);  tifd(:,j)=occurences'; end;end; tifd=tifd/sum(sum(tifd));method=upper(method);if nargout==0, tfrqview(tifd,[],t,method);end