Patent Document ID: 9520137
Application ID: 14907216
Patent Flag: 1

Claim One:
1. Method for suppressing a late reverberation of an audio signal, comprising the steps of: capturing an input signal formed by a superimposition of several delayed and attenuated versions of the audio signal; applying a time-frequency transformation to the input signal to obtain a complex time-frequency transform of the input signal; generating a frequency subsampled modulus from a modulus of the complex time-frequency transform of the input signal; generating a plurality of subsampled observation vectors from said frequency subsampled modulus; constructing a plurality of analysis dictionaries from the plurality of subsampled observation vectors; calculating a plurality of prediction vectors from the plurality of subsampled observation vectors and the plurality of analysis dictionaries by minimizing, for each prediction vector (α), the expression ∥{tilde over (X)}ν−D α α∥ 2 , which is an Euclidean norm of a difference between the subsampled observation vector ({tilde over (X)} ν ) associated with said each prediction vector (α) and the analysis dictionary (D α ) associated with said each prediction vector (α) multiplied by said each prediction vector (α), with a constraint ∥α∥ 1 ≦λ, according to which the norm 1 of said each prediction vector (α) is less than or equal to a maximum intensity parameter of the late reverberation (λ); generating a plurality of observation vectors from the modulus of the complex time-frequency transform of the input signal; constructing a plurality of synthesis dictionaries from a concatenation of the plurality of observation vectors; estimating a late reverberation spectrum from a multiplication of the plurality of synthesis dictionaries with the plurality of prediction vectors; and filtering the plurality of observation vectors to eliminate the late reverberation spectrum and to obtain a dereverberated signal modulus.