Hearing device comprising a speech intelligibility estimator
A hearing device, e.g. a hearing aid, comprises a) an input unit configured to provide at least one time-variant electric input signal representing sound, the at least one electric input signal comprising target signal components and optionally noise signal components, the target signal components originating from a target sound source; b) a signal processing unit for processing the at least one electric input signal and providing a processed signal; c) an output unit for creating output stimuli configured to be perceivable by the user as sound based on the processed signal from the signal processing unit; d) a speech presence probability prediction unit for repeatedly providing a measure of a predicted speech presence probability of the at least one electric input signal, or of a signal originating therefrom; and e) a speech intelligibility prediction unit for repeatedly providing a current measure of a predicted speech intelligibility of the at least one electric input signal, or of a signal originating therefrom. The speech intelligibility prediction unit is configured to determine said current measure of the predicted speech intelligibility in dependence of said measure of the predicted speech presence probability. A method of operating a hearing device is further disclosed. The invention may e.g. be used in hearing aids, headsets, earpieces (ear buds), etc.
1. A hearing device adapted for being worn by a user, the hearing device comprising
an input unit configured to provide at least one time-variant electric input signal representing sound,
a speech presence probability prediction unit for providing a measure of a predicted speech presence probability of the at least one electric input signal; and
a speech intelligibility prediction unit for providing a current measure of a predicted speech intelligibility of the at least one electric input signal,
wherein said speech intelligibility prediction unit is configured to determine said current measure of the predicted speech intelligibility in dependence of said measure of the predicted speech presence probability,
wherein the speech intelligibility prediction unit is configured to determine said current measure of the predicted speech intelligibility as a function (ƒ(.)) of a present value and a number of past values of said measure of the predicted speech presence probability, and
wherein the speech intelligibility prediction unit is configured to determine said current measure of the predicted speech intelligibility in dependence of a weighted sum of said present value and said number of past values of said measure of the predicted speech presence probability.
2. A hearing device according to claim 1 wherein said input unit is configured to provide said at least one electric input signal in a transform domain representation, or in a time-frequency representation (k,m), k being a frequency band index, m being a time index.
3. A hearing device according to claim 2 wherein the speech presence probability prediction unit is configured to determine said current measure of the predicted speech intelligibility in a number of time frequency units (k,m).
4. A hearing device according to claim 3 wherein the speech intelligibility prediction unit is configured to determine said current measure of the predicted speech intelligibility as a function of a present value and a number of past values of said measure of the predicted speech presence probability, wherein said present and said number of past values is M×K, where M is a number of time units and K is a number of frequency units.
5. A hearing device according to claim 1 wherein the speech intelligibility prediction unit is configured to determine said current measure of the predicted speech intelligibility in dependence of an, optionally normalized, sum of said present value and said number of past values of said measure of the predicted speech presence probability.
6. A hearing device according to claim 1 configured to provide that said function (ƒ(.)) is a data-driven model, learned from training data.
7. A hearing device according to claim 6 configured to provide that said function ƒ(.) is provided by a deep neural network whose parameters are learned offline, before use of the hearing device, using training data comprising estimated speech presence probabilities P k,m′ , k=1, . . . , K; m′=m−M+1, . . . m, for a particular noisy or processed time segment of a speech signal along with ground truth speech intelligibility of that speech segment, k being a frequency band index, m being a time index.
8. A hearing device according to claim 1 comprising a signal processing unit for processing the at least one electric input signal, wherein the signal processing unit comprises at least one processing algorithm configured to be applied to the at least one electric input signal or a signal or signals originating therefrom.
9. A hearing device according to claim 8 wherein the at least one processing algorithm comprises a noise reduction algorithm.
10. A hearing device according to claim 8 wherein the controller is configured to provide one or more processing parameters of the at least one processing algorithm, and wherein the one or more processing parameters is provided in dependence of the current measure of the predicted speech intelligibility.
11. A hearing device according to claim 1 comprising a controller (CTR) configured to provide appropriate processing parameters for use in the processing of the at least one electric input signal, or a signal or signals originating therefrom, in dependence of the current measure of the predicted speech intelligibility (Î).
12. A hearing device according to claim 11 wherein the input unit is configured to provide at least two time-variant electric input signals representing sound, and wherein the hearing aid comprises a beamformer configured to provide a beamformed signal in dependence of said at least two time-variant electric input signals and adaptively updated beamformer weights (w ij ) wherein the controller is configured to control the beamformer in dependence of the current measure of the predicted speech intelligibility (Î).
13. A hearing device according to claim 12 wherein the controller is configured to control the beamformer weights (w ij (k,m)) in dependence of the current measure of the predicted speech intelligibility (Î(m)) to increase omni-directionality of the beamformer, the higher the current measure of the predicted speech intelligibility (Î (m)).
14. A hearing device according to claim 1 being constituted by or comprising a hearing aid, a headset, an earphone, an ear protection device, or a combination thereof.
15. A method of operating a hearing device adapted for being worn by a user, the method comprising
providing at least one time-variant electric input signal representing sound,
providing a measure of a predicted speech presence probability of the at least one electric input signal, or of a signal originating therefrom;
providing a measure of a predicted speech intelligibility of the at least one electric input signal, or of a signal originating therefrom, and
determining said current measure of the predicted speech intelligibility in dependence of said measure of the predicted speech presence probability,
wherein said current measure of the predicted speech intelligibility is determined as a function (ƒ(.)) of a present value and a number of past values of said measure of the predicted speech presence probability, and
wherein said current measure of the predicted speech intelligibility is determined in dependence of a weighted sum of said present value and said number of past values of said measure of the predicted speech presence probability.
16. A non-transitory computer readable medium storing a computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method of claim 15 .
17. A computing device comprising
a speech presence probability prediction unit for providing a measure of a predicted speech presence probability of at least one time-variant electric input signal representing sound; and
a speech intelligibility prediction unit for providing a current measure of a predicted speech intelligibility of the at least one electric input signal,
wherein said speech intelligibility prediction unit is configured to determine said current measure of the predicted speech intelligibility in dependence of said measure of the predicted speech presence probability,
wherein the speech intelligibility prediction unit is configured to determine said current measure of the predicted speech intelligibility as a function (ƒ(.)) of a present value and a number of past values of said measure of the predicted speech presence probability, and
wherein the speech intelligibility prediction unit is configured to determine said current measure of the predicted speech intelligibility in dependence of a weighted sum of said present value and said number of past values of said measure of the predicted speech presence probability.
18. A non-transitory computer-readable medium on which is stored instructions which, when executed by a processor, performs a process comprising:
receiving at least one time-variant electric input signal representing sound from an input unit,
providing a measure of a predicted speech presence probability of the at least one electric input signal; and
providing a current measure of a predicted speech intelligibility of the at least one electric input signal,
wherein said providing the current measure of the predicted speech intelligibility is performed in dependence of said measure of the predicted speech presence probability,
wherein said current measure of the predicted speech intelligibility is determined as a function (ƒ(.)) of a present value and a number of past values of said measure of the predicted speech presence probability, and
wherein said current measure of the predicted speech intelligibility is determined in dependence of a weighted sum of said present value and said number of past values of said measure of the predicted speech presence probability.