Methods and apparatuses for setting a hearing aid to an omnidirectional microphone mode or a directional microphone mode
A method of automatic switching between omnidirectional (OMNI) and directional (DIR) microphone modes in a binaural hearing aid comprising a first microphone system, a second microphone system, where the first microphone system is adapted to be placed in or at a first ear of a user, the second microphone system is adapted to be placed in or at a second ear of said user, the method includes a measurement step, where the spectral and temporal modulations of first and second input signals are monitored, an evaluation step, where the spectral and temporal modulations of the first and second input signal are evaluated by the calculation of an evaluation index of speech intelligibility for each of said signals, and an operational step, where the microphone mode of the first and the second microphone systems of the binaural hearing aid are selected in dependence of the calculated evaluation indexes.
1. A method of automatic switching between a first microphone mode and a second microphone mode in a binaural hearing aid, the binaural hearing aid comprising a first microphone system for provision of a first input signal, and a second microphone system for provision of a second input signal, where the first microphone system is configured for use by a first ear of a user, and the second microphone system is configured for use by a second ear of the user, the method comprising:
obtaining modulations of the first input signal and the second input signal, wherein the act of obtaining the modulations of the first input signal and the second input signal is performed with at least the first microphone system being in the first microphone mode;
evaluating the modulations of the first input signal and the second input signal to determine a first evaluation index of speech intelligibility for the first input signal, and a second evaluation index of speech intelligibility for the second input signal; and
setting one or both of the first microphone system and the second microphone system based on a result from the act of evaluating;
wherein the act of setting comprises setting one of the first microphone system and the second microphone system to the second microphone mode, and setting the other one of the first microphone system and the second microphone system to the first microphone mode, based on the result from the act of evaluating the modulations of the first and second input signals, the second microphone mode being different from the first microphone mode.
2. The method of claim 1 , wherein the modulations comprise spectral modulations.
3. The method of claim 2 , wherein the modulations also comprise temporal modulations.
4. The method of claim 1 , wherein the modulations comprise temporal modulations.
5. The method of claim 1 , wherein the first microphone mode comprises a directional microphone mode.
6. The method of claim 1 , wherein the first microphone mode comprises an omni directional microphone mode.
7. The method of claim 1 , further comprising processing the first evaluation index and the second evaluation index.
8. The method of claim 7 , wherein the act of setting comprises setting one or both of the first microphone system and the second microphone system to the first microphone mode when a result of processing the first evaluation index and the second evaluation index indicates low speech intelligibility.
9. The method of claim 1 , wherein the act of setting comprises:
setting one of the first microphone system and the second microphone system with a corresponding one of the first evaluation index and the second evaluation index indicating highest speech intelligibility to an omnidirectional microphone mode, and
setting the other one of the first microphone system and the second microphone system with a corresponding one of the first evaluation index and the second evaluation index indicating lowest speech intelligibility to a directional microphone mode.
10. The method of claim 1 , wherein the first evaluation index of speech intelligibility is selected from the group consisting of: a speech transmission index (STI), a modified speech transmission index (mSTI), a spectral temporal modulation index (STMI), a modified temporal modulation index (mSTMI), an articulation index (AI), and a modified articulation index (mAI).
11. The method of claim 1 , wherein the act of setting comprises setting the first microphone system to a directional microphone mode.
12. The method of claim 1 , wherein the act of setting comprises setting the first microphone system to an omni directional microphone mode.
13. The method of claim 1 , wherein the act of setting comprises setting one or both of the first microphone system and the second microphone system to a directional microphone mode when a result from the act of evaluating indicates low speech intelligibility.
14. The method of claim 1 , wherein the act of obtaining the modulations of the first input signal and the second input signal is performed with the second microphone system being in an omni directional microphone mode.
15. A binaural hearing aid comprising:
at least one signal processor;
a first microphone system for provision of a first input signal;
a second microphone system for provision of a second input signal, where the first microphone system is adapted to be placed in or at a first ear of a user, and the second microphone system is adapted to be placed in or at a second ear of the user;
wherein the at least one signal processor is configured for:
obtaining modulations of the first input signal and the second input signal with at least the first microphone system being in a first microphone mode;
evaluating the modulations of the first input signal and the second input signal to determine a first evaluation index of speech intelligibility for the first input signal, and a second evaluation index of speech intelligibility for the second input signal; and
setting one or both of the first microphone system and the second microphone system based on a result from the act of evaluating;
wherein the at least one signal processor is configured for setting one of the first microphone system and the second microphone system to a second microphone mode, and setting the other one of the first microphone system and the second microphone system to the first microphone mode, based on the result from the act of evaluating the modulations of the first and second input signals, the second microphone mode being different from the first microphone mode.
16. The binaural hearing aid of claim 15 , wherein the modulations comprise spectral modulations.
17. The binaural hearing aid of claim 16 , wherein the modulations also comprise temporal modulations.
18. The binaural hearing aid of claim 15 , wherein the modulations comprise temporal modulations.
19. The binaural hearing aid of claim 15 , wherein the first microphone mode comprises a directional microphone mode.
20. The binaural hearing aid of claim 15 , wherein the first microphone mode comprises an omni directional microphone mode.
21. The binaural hearing aid of claim 15 , wherein the at least one signal processor is also configured to process the first evaluation index and the second evaluation index.
22. The binaural hearing aid of claim 21 , wherein the at least one signal processor is configured for setting one or both of the first microphone system and the second microphone system to the first microphone mode when a result of processing the first evaluation index and the second evaluation index indicates low speech intelligibility.
23. The binaural hearing aid of claim 15 , wherein the at least one signal processor is configured for:
setting one of the first microphone system and the second microphone system with a corresponding one of the first evaluation index and the second evaluation index indicating highest speech intelligibility to an omnidirectional microphone mode, and
setting the other one of the first microphone system and the second microphone system with a corresponding one of the first evaluation index and the second evaluation index indicating lowest speech intelligibility to a directional microphone mode.
24. The binaural hearing aid of claim 15 , wherein the first evaluation index of speech intelligibility is selected from the group consisting of: a speech transmission index (STI), a modified speech transmission index (mSTI), a spectral temporal modulation index (STMI), a modified temporal modulation index (mSTMI), an articulation index (AI), and a modified articulation index (mAI).
25. The binaural hearing aid of claim 15 , wherein the at least one signal processor is configured for setting the first microphone system to a directional microphone mode.
26. The binaural hearing aid of claim 15 , wherein the at least one signal processor is configured for setting the first microphone system to an omni directional microphone mode.
27. The binaural hearing aid of claim 15 , wherein the at least one signal processor is configured for setting one or both of the first microphone system and the second microphone system to a directional microphone mode when a result from the act of evaluating indicates low speech intelligibility.
28. The binaural hearing aid of claim 15 , wherein the at least one signal processor is configured for obtaining the modulations of the first input signal and the second input signal with the second microphone system being in an omni directional microphone mode.