ratedist_mu.m

linear time－frequency toolbox

function RateDist_mu(sig,a,M,mu,R)
%RATEDIST_MU  Rate distortion curves for mu-law encoded Gabor coefficients.
%   Usage:  RateDist_mu(sig,a,M,mu,R)
%
%   Input parameters
%      sig      : Input signal
%      a,M      : Parameters for dgt
%      mu       : mu constant for mu-law encoding
%      R        : List of bitrates to be examined
%
%   RATEDIST_MU(sig,a,M,mu,R) computes rate distortion curves
%   for mu-law encoded Gabor coefficients

% Author: Bruno Torresani

error(nargchk(5,5,nargin));

signorm = norm(sig);

gf=tfr_create('dgt',a,M,'pgauss','candual');
gc = tfr_ar(gf,sig);

SNR = zeros(max(R),1);

for Nbits = R,
  qgc = gc_mu_uquant(gc,Nbits,mu);
  rsig = tfr_sr(gf,qgc);
  err = norm(rsig - sig);
  SNR(Nbits) = 20*log10(signorm/err);
end

plot(R,SNR(R));

tfr_clear(gf);