Omnivision Technologies, Inc.

Chung-An Wang

Dong Shi

Cheng-Lun Hu

Lu Chang

A surveillance system includes an infrared sensor system coupled to output an infrared signal in response to receiving infrared light, and an audio recording system coupled to output an audio signal in response to recording sound. An image sensor is system coupled to output an image signal in response to receiving image light. A controller is coupled to the infrared sensor system, the audio recording system, and the image sensor system. The controller includes logic that when executed by the controller causes the surveillance system to perform operations including receiving the infrared signal from the infrared sensor system, activating the audio recording system to record the sound, and activating the image sensor system to output the image signal.

Reducing false alarms in surveillance systems

An electronic device to equalize sound includes a microphone coupled to receive the sound and output sound data. The sound has amplitude that changes with respect to time, and the sound includes one or more frequencies. The sound data indexes the amplitude with respect to the time. The electronic device also includes a controller coupled to microphone, and the controller includes logic that when executed by the controller causes the electronic device to perform operations. The operations may include: receiving the sound data from the microphone with the controller; adjusting the amplitude of the sound included in the sound data across the one or more frequencies using a filter disposed in the logic; and outputting filtered sound data.

Low complexity loudness equalization

Apparatuses and Methods of double talk detection for echo suppression in the power domain are disclosed herein. An example method includes comparing a power echo estimate signal to a microphone power signal, determining if the power echo estimate signal is greater than or less than the microphone power signal by a first threshold, based on the power echo estimate signal being greater than or less than the microphone power signal by the first threshold, disabling adaptation of filter coefficients of an adaptive filter of an echo suppressor, and based on the power echo estimate signal not being greater than or less than the microphone power signal by the first threshold, enabling adaptation of filter coefficients of an adaptive filter of an echo suppressor.

Double talk detection for echo suppression in power domain

A speaker system featuring automatic volume adjustment to avoid excess distortion includes a first converter for converting an input signal to an input frequency domain signal; and a second converter for converting a microphone signal to an environmental frequency domain signal. A distortion analyzer receives output of the first and second converter and determines at least one distortion level and provides at least one gain adjustment signal used to control a corrector to adjust gain of a speaker driver. The system performs a method of reducing distortion by automatically adjusting volume in each of a plurality of frequency bands including converting an input signal to a frequency domain input signal; converting a microphone signal to an environmental frequency domain signal; determining a distortion level; generating a gain adjustment signal; and adjusting gain of a signal provided to a speaker driver.

Dynamic output level correction by monitoring speaker distortion to minimize distortion

A noise-level estimator for a noise suppressor includes a power smoother filter providing smoothed power estimates in timeslices, a minimum follower that represents the lowest smoothed input power, and a maximum follower that represents the highest smoothed input power, the followers subject to leakage factors. The estimator has a speech probability detector receiving outputs of the power smoother and minimum follower; a nonstationary noise detector receiving outputs of both followers; and an estimator receiving outputs of the nonstationary noise detector, power smoother, and speech probability detector and providing a noise estimate. The method includes smoothing intensity of the frequency band; tracking minima and maxima of the smoothed intensity; determining speech-absence probability from the minima and the intensity; determining a nonstationary noise measure from the tracked minima and maxima; determining presence of nonstationary noise; and estimating noise from speech-absence probability, the nonstationary noise measure, and the intensity.

Method and audio noise suppressor using MinMax follower to estimate noise

A noise suppressor has a band extractor to separate signal by frequency band; and per-band units for each of band including noise estimator and SNR computation units. The per-band unit has a histogrammer to give histograms of current and past SNRs, and a gain-curve updater computes gain curves from the histogram. Gain curves are used to determine raw gains from current SNRs, raw gain is filtered and controls a variable gain unit to provide band-specific gain-adjusted, signals that are recombined into a noise-reduced frequency-domain output. Raw gain filtering may include finite-impulse-response filtering and weighted averaging of intermediate gains of a current and adjacent-band per-band unit. The method includes separating an input into frequency bands, estimating in-band noise, and deriving a band SNR. Then, histogramming the SNR and updating a gain curve from the histogram, and finding a raw gain using the gain curve and current SNR.

Method and audio noise suppressor using nonlinear gain smoothing for reduced musical artifacts

An echo canceller includes a fast Fourier transform (FFT) unit to provide frequency domain representation (FD) of an input. A multiband adaptive filter receives the FD of the input and provides an FD filter output, the adaptive filter is a finite input response (FIR) digital filter. Another FFT unit provides an FD of a microphone signal, and a summer adds the FD filter output to the FD of the microphone signal to provide echo-canceller FD output. A feedback subsystem uses the echo-canceller FD output to adjust filter coefficients of at least a first, a second, and a third frequency band of the multiband adaptive filter to minimize uncancelled output in the echo-canceller FD output. The feedback subsystem adjusts the filter coefficients of the second frequency band of the adaptive filter according to uncancelled output in the first, second, and third frequency bands of the echo-canceller FD output.

Growing community of inventors

Singapore, Singapore

Chung-An Wang