Monaural intrusive speech intelligibility predictor unit, a hearing aid and a binaural hearing aid system

A monaural speech intelligibility predictor unit adapted for receiving a target signal comprising speech in an essentially noise-free version s and in a noisy and/or processed version x, the monaural speech intelligibility predictor unit being configured to provide as an output a final monaural speech intelligibility predictor value d indicative of a listener's perception of said noisy and/or processed version x of the target signal, the monaural speech intelligibility predictor unit comprising

• A first input unit for providing a time-frequency representation s(k,m) of said noise-free version s of the target signal, k being a frequency bin index, k=1, 2, . . . , K, and m being a time index;
• A second input unit for providing a time-frequency representation x(k,m) of said noisy and/or processed version x of the target signal, k being a frequency bin index, k=1, 2, . . . , K, and m being a time index;
• A first envelope extraction unit for providing a time-frequency sub-band representation sj(m) of the noise-free version s of the target signal representing temporal envelopes, or functions thereof, of frequency sub-band signals sj(m) of said noise-free target signal, j being a frequency sub-band index, j=1, 2, . . . , J, and m being the time index;
• A second envelope extraction unit for providing a time-frequency sub-band representation xj(m) of the noisy and/or processed version x of the target signal representing temporal envelopes, or functions thereof, of frequency sub-band signals xj(m) of said noisy and/or processed version of the target signal, j=1, 2, . . . , J, and m being the time index;
• A first time-frequency segment division unit for dividing said time-frequency sub-band representation sj(m) of the noise-free version s of the target signal into time-frequency segments Sm corresponding to a number N of successive samples of said sub-band signals;
• A second time-frequency segment division unit for dividing said time-frequency sub-band representation xj(m) of the noisy and/or processed version x of the target signal into time-frequency segments Xm corresponding to a number N of successive samples of said sub-band signals;
• A normalization and transformation unit configured to provide at least one normalization and/or transformation operation of rows and at least one normalization and/or transformation operation of columns of the time-frequency segments Sm and Xm;
• An intermediate speech intelligibility calculation unit adapted for providing intermediate speech intelligibility coefficients dm estimating an intelligibility of said time-frequency segment Xm, said intermediate speech intelligibility coefficients dm being based on said essentially noise-free, normalized and/or transformed time frequency segments {tilde over (S)}m, and said noisy and/or processed, normalized and/or transformed time-frequency segments {tilde over (X)}m;
• A final monaural speech intelligibility calculation unit for calculating a final monaural speech intelligibility predictor d estimating an intelligibility of said noisy and/or processed version x of the target signal by combining, e.g. by averaging, or by applying a MIN or MAX-function to, said intermediate speech intelligibility coefficients dm, or a transformed version thereof, over time.