33 results about "Double talk detector" patented technology

A method and system for processing subband signals using adaptive filters is provided. The system is implemented on an oversampled WOLA filterbank. Inputs signals are oversampled. The system includes an adaptive filter for each subband, and the functionality of improving the convergence properties of the adaptive filter. For example, the convergence property is improved by whitening the spectra of the oversampled subband signals and / or affine projection algorithm. The system is applicable to echo and / or noise cancellation. Adaptive step size control, adaptation process control using Double-Talk detector may be implemented. The system may further implement a non-adaptive processing for reducing uncorrelated noise and / or cross-talk resistant adaptive noise cancellation.

An echo cancellation invention which does away with the need for an accurate double-talk detector, while maintaining a higher adaptation gain for quicker convergence and also providing increased stability. It does this by operating two filter models of the acoustic path in parallel. One model is adapted continuously to find the most accurate model of the echo path, while the other is not. The echo canceller output is taken from the filter that is not adapted. A comparison of the residual error (echo) is done between the model being adapted and the model being listened to at regular intervals. When the model being adapted has less error (echo) than the model being listened to its filter coefficients are copied to the other model. If the model being adapted has greater error (echo) than the other model (caused by noise diverging the adaptation process) then the adapted model has its coefficients overwritten by the filter that is listened to. This process keeps error from accumulating in the adapted filter by removing divergence at regular intervals (improving overall convergence). Since the output is taken from the filter that is not adapted, higher adaptation gains may be used without fear of the user hearing any effects of adapting with a higher gain in the presence of noise.

A double-talk detector finds an estimated power value of near end background noise based on a residual signal by a noise estimator; the average power of a transmitter input signal by a transmitter average power calculator; the average power of a receiver input signal by a receiver average power calculator; and an estimated echo path attenuation value through a predetermined echo path attenuation value estimating process based on the estimated power value of the near end background noise, the average power of the transmitter input signal and the average power of the receiver input signal by an attenuation value estimator. The double-talk detector detects a double-talk state based on the estimated echo path attenuation value, the average power of the transmitter input signal and the average power of the receiver input signal by a double-talk determiner to control update of the coefficient of an adaptive filter.

An echo canceling circuit comprising a double talk detector, an upper band signal filter configured to pass only near-end upper band signals to the double talk detector and remove lower band signals, an adaptive filter circuit, a control circuit operatively coupled to the double talk detector and to the adaptive filter circuit, and a threshold estimator configured to iteratively calculate an upper adaptive decision threshold value and a lower adaptive decision threshold value. The double talk detector declares near-end speech to be present if an estimated power level of the upper band signals exceeds the upper adaptive decision threshold value, and declares the near-end speech to be absent if the estimated power level of the upper band signals falls below the lower adaptive decision threshold value for a predetermined number of iterative cycles.

An echo canceler is constituted of an adaptive filter for generating an echo replica simulating an echo occurring in an echo path lying between a speaker and a microphone, a subtracter for subtracting the echo replica from the sound received by the microphone, a double-talk detector which extracts a prescribed frequency band, in which the signal level is attenuated due to the echo path, from the output signal of the subtracter and which determines a double-talk event with respect to the extracted frequency band, and a controller for controlling the adaptive filter to update the echo replica in the double-talk event.

The system describes a karaoke system that enhances the experience of singing along with music, but without the need to display the lyrics. The system includes a combination of a vocal track reducer and an echo canceller, decision logic for determining when a person is talking or singing (double-talk detector) and a method for “ducking” (i.e., attenuating) the vocal track when the singing is detected. No special CD or DVD with lyric tracks is required, making the system capable of working with CD, mp3, AM, FM, HD radio, satellite radio signals, or any other suitable content source. The result is that any content source may potentially be used as a karaoke soundtrack without any pre-modification.

An echo canceler includes an adaptive filter that adapts to changes in an echo path, a double-talk detector, and an echo path change detector. The echo path change detector estimates the loss on the echo path, thereby distinguishing true double-talk from apparent double-talk detected by mistake because of a change in the echo path. The adaptive filter continues normal adaptation during the apparent double-talk state when echo path change is also detected. The necessary conditions for detection of echo path change preferably include a small separation between the estimated loss on the echo path and a long-term smoothed value of the estimated loss. The echo path change detector is useful in, for example, the cancellation of line echo in telephone switching systems.

An echo canceller (106) can include a first multi-band filter (152) which receives a first input signal (108) and generates a first plurality of sub-band signals (110, 111, 112), and a second multi-band filter (154) which receives a second input signal (122) and generates a second plurality of sub-band signals (156, 157, 158). The echo canceller also can include a plurality of double talk detectors (168, 169, 170) that each generate a double talk flag (182, 183, 184) based on at least a respective one of the first sub-band signals and a respective one of the second sub-band signals.

An echo canceler includes an recursive least squares lattice to whiten a far-end signal s1(t) and provide whitened time delays. The echo canceler further decorrelates a microphone signal based on the whitened time delays to reduce echoes of the far-end signal s1(t) that are contained in the microphone signal x2(t). The echo canceler does not use a double-talk detector and avoids all problems inherent with their use. Thus, speaker phones, and other communication devices, can continuously operate in full-duplex mode of operation thereby providing natural conversational hands-free communication.

The invention generally relates to measurement of speech intelligibility in a mobile communication network component handling two-way communication between two ends, typically a near-end and a far-end. A basic idea is to simulate (Sl) two-way speech communication based on test signals adapted for speech intelligibility measurements, detect double-talk (S2) during the simulated speech communication by using a double-talk detector, and perform (S3) speech intelligibility measurements only at periods of double-talk. In this way, it is for example possible to take the effects of echo into account in the speech intelligibility measurements, while avoiding undesirable effects from non-linear processing (and possible added comfort noise) in the signal path for which speech intelligibility is measured.; Optionally, the operation of voice enhancement devices can be adjusted (S4) in response to the estimated speech intelligibility.

An apparatus for canceling an echo signal in a mobile terminal of a mobile communication system. A double talk detector (DTD) receives a first signal by canceling an estimated echo signal from a signal received through a microphone, outputs the first signal, and outputs the first and a second signal comprising a background noise signal and a residual echo signal during a non-double talk. An Auto-Regressive (AR) analysis and inverse filtering unit receives the second signal from the DTD, and whitens the second signal. A pitch analysis and inverse filtering unit receives the whitened signal, and cancels a pitch value remaining therein by performing pitch analysis and inverse filtering on the whitened signal. A noise canceller receives the pitch-cancelled whitened signal and the first signal output from the DTD, canceling a residual echo signal and a background noise signal from the first signal using the pitch-cancelled whitened signal.

An apparatus and method for canceling an acoustic echo. In the apparatus, a double-talk detector detects whether a current period is a double-talk period or a single-talk period by determining whether a remote talker's signal and a local talker's signal are received simultaneously or at different times. A noise-robust affine projection (NRAP) adaptive filter estimates an acoustic echo included in the remote talker's signal using an NRAP algorithm if the detected current period is a double-talk period. A normalized least mean square (NLMS) adaptive filter estimates the acoustic echo included in the remote talker's signal using an NLMS algorithm if the detected current period is a single-talk period. The apparatus then generates an echo-canceled local talker's signal.

The invention discloses an improved double-talk detection device and detection method based on double statistics, and belongs to the technical field of audio processing. The detection device comprisesa microphone, a double-talk detection module, an adaptive filtering module, an echo estimation loop module and a signal processing module; a signal input end of the double-talk detection module is respectively connected with a signal output end of the microphone and a remote voice signal output end; a signal output end of the double-talk detection module is respectively connected with a signal input end of the adaptive filtering module and an output end of the signal processing module; the double-talk detection module is connected with the echo estimation loop module; and an input end of theecho estimation loop module is connected with the remote voice signal output end. The detection method provided by the invention can significantly improve the detection sensitivity of a DTD (Double-Talk Detector) algorithm, and has the characteristics of being low in computational complexity and good in system robustness.

An echo canceler includes an adaptive filter that adapts to changes in an echo path, a double-talk detector, and an echo path change detector. The echo path change detector estimates the loss on the echo path, thereby distinguishing true double-talk from apparent double-talk detected by mistake because of a change in the echo path. The adaptive filter continues normal adaptation during the apparent double-talk state when echo path change is also detected. The necessary conditions for detection of echo path change preferably include a small separation between the estimated loss on the echo path and a long-term smoothed value of the estimated loss. The echo path change detector is useful in, for example, the cancellation of line echo in telephone switching systems.

An echo canceler includes an recursive least squares lattice to whiten a far-end signal s1(t) and provide whitened time delays. The echo canceler further decorrelates a microphone signal based on the whitened time delays to reduce echoes of the far-end signal s1(t) that are contained in the microphone signal x2(t). The echo canceler does not use a double-talk detector and avoids all problems inherent with their use. Thus, speaker phones, and other communication devices, can continuously operate in full-duplex mode of operation thereby providing natural conversational hands-free communication.

An electronic device, a method of cancelling an echo signal thereof, and a non-transitory computer readable recording medium are provided. The electronic device includes a speaker configured to output a sound corresponding to a first audio signal, a microphone configured to acquire a surrounding sound of the electronic device to generate a second audio signal; a double-talk detector (DTD) configured to determine whether a double-talk state, in which an echo signal and a noise signal of the first audio signal are included in the second audio signal, occurs; and an acoustic echo canceller (AEC) configured to generate an estimated echo signal corresponding to the echo signal of the first audio signal based on an adaptive filter (AF) in response to the DTD determining that the double-talk state does not occur and cancel the generated estimated echo signal from the second audio signal to detect an error signal.

An apparatus for canceling an echo signal in a mobile terminal of a mobile communication system. A double talk detector (DTD) receives a first signal by canceling an estimated echo signal from a signal received through a microphone, outputs the first signal, and outputs the first and a second signal comprising a background noise signal and a residual echo signal during a non-double talk. An Auto-Regressive (AR) analysis and inverse filtering unit receives the second signal from the DTD, and whitens the second signal. A pitch analysis and inverse filtering unit receives the whitened signal, and cancels a pitch value remaining therein by performing pitch analysis and inverse filtering on the whitened signal. A noise canceller receives the pitch-cancelled whitened signal and the first signal output from the DTD, canceling a residual echo signal and a background noise signal from the first signal using the pitch-cancelled whitened signal.

A method for detecting a double-talk condition and an echo cancellation system using the same are introduced herein. According to an exemplary embodiment, the method may be adapted to an double-talk detector of an echo cancellation system and includes the following steps: obtaining an input signal with a first power; computing a second power, wherein the second power is a power combination of at least one estimated signal; determining whether the double-talk condition occurs according to a relationship between the first power and the second power, when the first power is larger than the second power, the double-talk condition occurs.

The invention generally relates to measurement of speech intelligibility in a mobile communication network component handling two-way communication between two ends, typically a near-end and a far-end. A basic idea is to simulate (Sl) two-way speech communication based on test signals adapted for speech intelligibility measurements, detect double-talk (S2) during the simulated speech communication by using a double-talk detector, and perform (S3) speech intelligibility measurements only at periods of double-talk. In this way, it is for example possible to take the effects of echo into accountin the speech intelligibility measurements, while avoiding undesirable effects from non-linear processing (and possible added comfort noise) in the signal path for which speech intelligibility is measured.; Optionally, the operation of voice enhancement devices can be adjusted (S4) in response to the estimated speech intelligibility.

An echo canceler is constituted of an adaptive filter for generating an echo replica simulating an echo occurring in an echo path lying between a speaker and a microphone, a subtracter for subtracting the echo replica from the sound received by the microphone, a double-talk detector which extracts a prescribed frequency band, in which the signal level is attenuated due to the echo path, from the output signal of the subtracter and which determines a double-talk event with respect to the extracted frequency band, and a controller for controlling the adaptive filter to update the echo replica in the double-talk event.

An echo canceller for executing adaptive processing for canceling an echo component mixed with an audio input signal includes a volume ratio learner configured to compute a volume ratio between an audio output signal externally outputted and the audio input signal mixed with an echo component caused by reflection of the audio output signal to the audio input signal, thereby learning the volume ratio in a regular status in own apparatus, a double-talk detector configured to detect the double-talk status depending on whether a this-time volume ratio computed this time adapts to a double-talk status predicted by the learning of volume ratio and an echo cancel processor configured to control a learning operation of the echo component for the adaptive processing on the basis of a result of the double-talk status detection by the double-talk detector.

A method for detecting a double-talk condition and an echo cancellation system using the same are introduced herein. According to an exemplary embodiment, the method may be adapted to an double-talk detector of an echo cancellation system and includes the following steps: obtaining an input signal with a first power; computing a second power, wherein the second power is a power combination of at least one estimated signal; determining whether the double-talk condition occurs according to a relationship between the first power and the second power, when the first power is larger than the second power, the double-talk condition occurs.

A double talk, detector (14) for controlling the echo path estimation in a telecommunication system by indicating when a received coded speech signal (6) is dominated by a non-echo signal (5), i.e. that so-called double talk exists. This is determined by extracting the LSPs from a coded speech frame of the received coded speech signal when the signal power exceeds a first threshold value, converting each of said extracted LSPs into LSPs (Line Spectral Frequencies), Qi, and calculating the distance between each two adjacent LSFs. For each distance that is smaller than a second threshold, a spectral peak is located between the two LSF, and it is determined whether said spectral peak is an echo or not. When a predetermined number of non-echo spectral peaks are located in the received speech signal (6), double talk will be indicated, and the echo path estimation may be disabled.