A method, a system and a program product for evaluating an intestinal function using bowel sounds are disclosed. The method comprises the following steps: A. continuously monitoring an abdominal cavity of an examinee within a specific time by using an audio collection apparatus, collecting a bowel sound signal of an intestinal tract inside the abdominal cavity, and converting the bowel sound signal into a digital signal; B. using higher-order statistics (HOS), by a processing unit, to remove noise from the digital signal; C. using a fractal dimension algorithm, by the processing unit, to capture a high-complexity feature from the digital signal, and defining the high-complexity feature as an intestinal motility signal, and D. evaluating the intestinal function of the examinee, by the processing unit, according to the intestinal motility signal.

For example, a controller of an Active Acoustic Control (AAC) system may be configured to process input information, the input information including AAC configuration information corresponding to a configuration of AAC in a sound control zone; a plurality of noise inputs representing acoustic noise at a plurality of noise sensing locations; and a plurality of residual-noise inputs representing acoustic residual-noise at a plurality of residual-noise sensing locations within the sound control zone. For example, the controller may determine a sound control pattern to control sound within the sound control zone based on the AAC configuration information, the plurality of noise inputs, and the plurality of residual-noise inputs. For example, the controller may output the sound control pattern to a plurality of acoustic transducers.

An integrated circuit for implementing at least a portion of a personal audio device may include a processing circuit to implement an adaptive filter having a response that generates an anti-noise signal to reduce the presence of the ambient audio sounds at an error microphone, implement a coefficient control block that shapes the response of the adaptive filter in conformity with the error microphone signal by computing coefficients that determine the response of the adaptive filter to minimize the ambient audio sounds at the error microphone, and responsive to detecting a condition that triggers a reset of the adaptive filter, increment the coefficients in a plurality of steps from initial values of the coefficients at a time of triggering the reset to final values of the coefficients at a conclusion of the reset.

A signal processing apparatus is configured to preprocess a sound wave signal and output a processed audio signal through an electromagnetic wave. The signal processing apparatus includes: a receiving unit, configured to receive at least one sound wave signal; a conversion unit, configured to convert the at least one sound wave signal to at least one audio signal; a positioning unit, configured to determine position information related to the at least one sound wave signal; a processing unit, configured to determine a sending time point of at least one audio signal based on the position information and a first time point, where the first time point is a time point at which the receiving unit receives the at least one sound wave signal; and a sending unit, configured to send the at least one audio signal through the electromagnetic wave.

This application discloses a method for reducing an occlusion effect of an earphone, and a related apparatus. The method is applied to an earphone having at least one microphone and a speaker. The method includes: detecting occurrence of at least one of the following events: a user speaks and the user is in a motion state; and triggering at least one of the following operations in response to the at least one event: processing the user's sound signal based on the at least one microphone to suppress an occlusion effect of the earphone, and playing an audio by using the speaker, to mask a sound signal in the user's auditory canal. Embodiments of this application can reduce or even eliminate the earphone occlusion effect, to improve user experience.

Methods and systems are provided for automatic noise control. Automatic noise control includes controlling a shadow noise control transfer function based on a shadow error signal and a filtered or unfiltered reference signal, generating the shadow error signal based on a filtered or unfiltered shadow anti-noise signal and an error signal, and substituting the noise control transfer function by the shadow noise control transfer function if the shadow error signal is smaller than the error signal.

Methods and systems are provided for an automatic noise control system. Automatic noise control includes evaluating an amplitude of an acceleration acting on an acceleration sensor and generating a reference signal representative of the amplitude of the acceleration, the acceleration being representative of unwanted noise sound generated by a noise source, filtering the reference signal with a noise control transfer function to generate an anti-noise signal, and converting with a loudspeaker the anti-noise signal into anti-noise sound.

A sound pick-up device includes an adaptive filter configured to generate, from a reference signal, an estimated noise signal indicating a component of a noise signal contained in an input signal, a noise elimination signal generator configured to generate a noise elimination signal by subtracting the estimated noise signal from the input signal, a filter coefficient update unit configured to update a filter coefficient of the adaptive filter using the noise elimination signal, and a sample position identification unit configured to identify at least one signal sample position among a plurality of signal sample positions from a signal sample position where the noise elimination signal has a maximum absolute value to a signal sample position where the noise elimination signal has an absolute value that is largest at a predetermined order, in which the filter coefficient update unit updates the filter coefficient at the at least one signal sample position.

Embodiments of active noise control (ANC) headphones and operating methods thereof are disclosed herein. In one example, a headphone includes a speaker, an internal microphone, and a processor. The speaker is configured to play an audio of interest based on an audio source signal. The internal microphone is configured to obtain a mixed audio signal including a noise signal and the audio of interest played by the speaker. The processor is configured to determine a first current system parameter of the headphone based on the mixed audio signal at a first time point, and determine if the first current system parameter of the headphone is higher than a predetermined threshold to determine if the headphone is worn by a user.

Various aspects include a wearable audio device having active noise reduction (ANR). In some cases, an ANR system for a wearable audio device includes: a fixed filter that receives a signal from a feedback microphone and outputs a noise reduction signal, where the fixed filter is configured to provide ANR with a nominal loop gain; and a tunable filter that outputs an adjusted noise reduction signal by modulating the nominal loop gain in response to low frequency noise being detected in the noise reduction signal, where modulating the nominal loop gain includes reducing low frequency ANR performance.