Method for directional signal processing for a hearing aid and hearing system
A method performs directional signal processing for a hearing aid. First and second input transducers of the hearing aid generate first and second input signals, respectively, from a sound signal. A first calibration directional signal which has a relative attenuation in the direction of a first useful signal source is generated from the first and second input signals, and a second calibration directional signal which has a relative attenuation in the direction of a second useful signal source is generated from the first and second input signals. A relative gain parameter is determined from the first and second calibration directional signals. First and second processing directional signals are generated from both the first and second input signals. A source-sensitive directional signal is generated from the first and second processing directional signals and the relative gain parameter. An output signal of the hearing aid is generated from the source-sensitive directional signal.
1. A method for directional signal processing for a hearing aid, which comprises the steps of:
generating, via a first input transducer of the hearing aid, a first input signal from a sound signal in an environment;
generating, via a second input transducer of the hearing aid, a second input signal from the sound signal in the environment;
generating a first calibration directional signal having a relative attenuation in a direction of a first useful signal source in the environment on a basis of the first input signal and on a basis of the second input signal;
generating a second calibration directional signal having a relative attenuation in a direction of a second useful signal source in the environment on a basis of the first input signal and on a basis of the second input signal;
determining a relative gain parameter on a basis of the first calibration directional signal and the second calibration directional signal;
generating a first processing directional signal and a second processing directional signal on a basis of both the first input signal and the second input signal;
generating a source-sensitive directional signal on a basis of the first processing directional signal, the second processing directional signal and the relative gain parameter; and
generating an output signal of the hearing aid on a basis of the source-sensitive directional signal.
2. The method according to claim 1 , which further comprises:
determining a first instantaneous gain parameter on a basis of the first calibration directional signal;
determining a second instantaneous gain parameter on a basis of the second calibration directional signal; and
determining the relative gain parameter on a basis of the first instantaneous gain parameter and the second instantaneous gain parameter.
3. The method according to claim 2 , which further comprises:
determining a reference signal strength in the direction of the second useful signal source;
determining a derived signal strength in the direction of the first useful signal source on a basis of the relative gain parameter and on a basis of the reference signal strength; and
determining a complex superposition parameter for a superposition of the first processing directional signal with the second processing directional signal on a basis of the derived signal strength, and the source-sensitive directional signal is generated on a basis of an associated superposition.
4. The method according to claim 1 , which further comprises generating a first intermediate signal and a second intermediate signal on a basis of both the first input signal and the second input signal.
5. The method according to claim 4 , which further comprises:
generating the first intermediate signal on a basis of a time-delayed superposition of the first input signal with the second input signal, which is implemented by means of a first delay parameter; and/or
generating the second intermediate signal on a basis of a time-delayed superposition of the second input signal with the first input signal, which is implemented by means of a second delay parameter.
6. The method according to claim 5 , which further comprises:
generating the first intermediate signal as a front-facing cardioid directional signal; and/or
generating the second intermediate signal as a rear-facing cardioid directional signal.
7. The method according to claim 4 , which further comprises generating both the first calibration directional signal and the second calibration directional signal on a basis of both the first intermediate signal and the second intermediate signal.
8. The method according to claim 4 , which further comprises:
generating the first processing directional signal from the first intermediate signal; and/or
generating the second processing directional signal from the second intermediate signal.
9. The method according to claim 4 , which further comprises:
forming the first processing directional signal as a first asymmetrical superposition signal on a basis of a time-delayed superposition of the first input signal with the second input signal, which is implemented by means of asymmetrical first weighting factors; and/or
forming the second processing directional signal as a second asymmetrical superposition signal on a basis of a time-delayed superposition of the second input signal with the first input signal, which is implemented by means of asymmetrical second weighting factors.
10. The method according to claim 9 , which further comprises:
determining a reference signal strength in the direction of the second useful signal source;
determining a derived signal strength in the direction of the first useful signal source on a basis of the relative gain parameter and on a basis of the reference signal strength;
determining the asymmetrical first weighting factors and/or the asymmetrical second weighting factors for the first asymmetrical superposition signal and/or the second asymmetrical superposition signal on a basis of the derived signal strength; and
generating the source-sensitive directional signal as the first processing directional signal and/or the second processing directional signal on a basis of the first asymmetrical superposition signal and/or the second asymmetrical superposition signal.
11. The method according to claim 1 , wherein:
the first calibration directional signal has a maximum attenuation in the direction of the first useful signal source; and/or
the second calibration directional signal has a maximum attenuation in the direction of the second useful signal source.
12. The method according to claim 1 , which further comprises:
generating the first calibration directional signal by means of adaptive directional microphony; and/or
generating the second calibration directional signal by means of the adaptive directional microphony.
13. A hearing system, comprising:
a hearing aid having a first input transducer for generating a first input signal from a sound signal in an environment and a second input transducer for generating a second input signal from the sound signal in the environment; and
a controller configured to carry out a method for directional signal processing for said hearing aid, said controller configured to:
generate a first calibration directional signal having a relative attenuation in a direction of a first useful signal source in the environment on a basis of the first input signal and on a basis of the second input signal;
generate a second calibration directional signal having a relative attenuation in a direction of a second useful signal source in the environment on a basis of the first input signal and on a basis of the second input signal;
determine a relative gain parameter on a basis of the first calibration directional signal and the second calibration directional signal;
generate a first processing directional signal and a second processing directional signal on a basis of both the first input signal and the second input signal;
generate a source-sensitive directional signal on a basis of the first processing directional signal, the second processing directional signal and the relative gain parameter; and
generate an output signal of the hearing aid on a basis of the source-sensitive directional signal.