In-vehicle audio processing apparatus
First Claim
1. An in-vehicle audio processing apparatus mounted in a vehicle, the apparatus comprising:
- an audio output device;
a speaker for outputting an output audio signal as an output sound that is output from the audio output device;
a microphone for outputting an input audio signal, the input audio signal based on sound that is picked up at the microphone;
an adaptive filter operative to perform an adaptation operation to cause a first transfer function to approximate a second transfer function of a system whose input is the output audio signal that is output from the audio output device and whose output is the input audio signal from the microphone, to apply the first transfer function to the output audio signal, and to output a simulation audio signal which simulates a component corresponding to the output sound contained in the input audio signal;
a vehicle-status collecting unit for collecting a vehicle status regarding surroundings of the in-vehicle audio processing apparatus; and
an adaptive characteristic controller for controlling a control parameter of the adaptation operation of the adaptive filter based on the vehicle status collected by the vehicle-status collecting unit.
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Abstract
On the basis of status information on a vehicle collected by a status information input interface from a navigation device, an ECU, and sensors, an S/N ratio estimating unit estimates, as an S/N ratio, the level of the ratio between the power of a component corresponding to audio-device output sound y(j) and that corresponding to noise sound n(j) contained in a microphone output signal. A transfer-function variation estimating unit estimates the level of a variation in a transfer function of an audio-device output audio signal transfer system. An adaptive characteristics controller controls a characteristic of a coefficient updating operation of a tap coefficient of an FIR filter performed by a coefficient updating unit of an adaptive filter, i.e., an adaptation (learning) characteristic of the adaptive filter, in response to the S/N ratio level and the level of the variation in the transfer function.
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Citations
20 Claims
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1. An in-vehicle audio processing apparatus mounted in a vehicle, the apparatus comprising:
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an audio output device;
a speaker for outputting an output audio signal as an output sound that is output from the audio output device;
a microphone for outputting an input audio signal, the input audio signal based on sound that is picked up at the microphone;
an adaptive filter operative to perform an adaptation operation to cause a first transfer function to approximate a second transfer function of a system whose input is the output audio signal that is output from the audio output device and whose output is the input audio signal from the microphone, to apply the first transfer function to the output audio signal, and to output a simulation audio signal which simulates a component corresponding to the output sound contained in the input audio signal;
a vehicle-status collecting unit for collecting a vehicle status regarding surroundings of the in-vehicle audio processing apparatus; and
an adaptive characteristic controller for controlling a control parameter of the adaptation operation of the adaptive filter based on the vehicle status collected by the vehicle-status collecting unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for controlling an adaptation operation of an adaptive filter in an in-vehicle audio processing apparatus mounted in a vehicle, the in-vehicle audio processing apparatus including an audio output device, a speaker for outputting an output audio signal output from the audio output device as an output sound, a microphone for outputting a picked up sound as an input audio signal, and an adaptive filter for performing an adaptation operation of causing a first transfer function of the adaptive filter to approximate a second transfer function of a system whose input is the output audio signal and whose output is the input audio signal and for applying the first transfer function of the adaptive filter to the output audio signal and outputting a simulation audio signal which simulates a component corresponding to the output sound contained in the input audio signal, the method comprising:
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a first step of collecting a vehicle status regarding surroundings of the in-vehicle audio processing apparatus; and
a second step of controlling a control parameter of the adaptation operation of the adaptive filter in response to the collected vehicle status. - View Dependent Claims (19, 20)
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Specification