Patents by Inventor Amit Singh Chhetri
Amit Singh Chhetri has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9820036Abstract: Sound is banked laterally over an array of microphones arranged on a rear surface of a device. Sound enters a duct behind the device from different directions via inlets along the sides of the device. The duct directs the sound waves across the microphone array. An effective direction from which the banked sounds originated is determined, relative to a front of the device. Based on the determined effective direction, the device applies spatial filtering to isolate the received sound waves, selectively increasing a signal-to-noise ratio of sound from the selected source and at least partially occluding sounds from other sources.Type: GrantFiled: December 30, 2015Date of Patent: November 14, 2017Assignee: Amazon Technologies, Inc.Inventors: Charles Tritschler, Amit Singh Chhetri, Philip Ryan Hilmes
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Patent number: 9754605Abstract: A multi-channel acoustic echo cancellation (AEC) system that includes a step-size controller that dynamically determines a step-size value for each channel and each tone index on a frame-by-frame basis. The system determines the step-size value based on a normalized squared cross-correlation (NSCC) between an estimated echo signal and an error signal, allowing the AEC system to converge quickly when an acoustic room response changes while providing stable steady-state error by avoiding misadjustments due to noise sensitivity and/or near-end speech. The step-size value can be determined using fractional weighting that takes into account a signal strength of each channel.Type: GrantFiled: June 9, 2016Date of Patent: September 5, 2017Assignee: AMAZON TECHNOLOGIES, INC.Inventor: Amit Singh Chhetri
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Patent number: 9734845Abstract: In a speech-based system, a wake word or other trigger expression is used to preface user speech that is intended as a command. The system receives multiple directional audio signals, each of which emphasizes sound from a different direction. The signals are monitored and analyzed to detect the directions of interfering audio sources such as televisions or other types of electronic audio players. One of the directional signals having the strongest presence of speech is selected to be monitored for the trigger expression. If the directional signal corresponds to the direction of an interfering audio source, a more strict standard is used to detect the trigger expression. In addition, the directional audio signal having the second strongest presence of speech may also be monitored to detect the trigger expression.Type: GrantFiled: June 26, 2015Date of Patent: August 15, 2017Assignee: Amazon Technologies, Inc.Inventors: Yue Liu, Praveen Jayakumar, Amit Singh Chhetri, Ramya Gopalan
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Patent number: 9704478Abstract: Features are disclosed for filtering portions of an output audio signal in order to improve automatic speech recognition on an input signal which may include a representation of the output signal. A signal that includes audio content can be received, and a frequency or band of frequencies can be selected to be filtered from the signal. The frequency band may correspond to a desired frequency band for speech recognition. An input signal can be obtained comprising audio data corresponding to a user utterance and presentation of the output signal. Automatic speech recognition can be performed on the input signal. In some cases, an acoustic model trained for use with such frequency band filtering may be used to perform speech recognition.Type: GrantFiled: December 2, 2013Date of Patent: July 11, 2017Assignee: Amazon Technologies, Inc.Inventors: Shiv Naga Prasad Vitaladevuni, Amit Singh Chhetri, Phillip Ryan Hilmes, Rohit Prasad
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Patent number: 9689960Abstract: The systems, devices, and processes described herein may identify a beam of a voice-controlled device that is directed toward a reflective surface, such as a wall. The beams may be created by a beamformer. An acoustic echo canceller (AEC) may create filter coefficients for a reference sound. The filter coefficients may be analyzed to identify beams that include multiple peaks. The multiple peaks may indicate presence of one or more reflective surfaces. Using the amplitude and the time delay between the peaks, the device may determine that it is close to a reflective surface in a direction of the beam.Type: GrantFiled: April 4, 2013Date of Patent: June 27, 2017Assignee: Amazon Technologies, Inc.Inventors: William Folwell Barton, Kenneth Edgar Hild, II, Ramya Gopalan, Kavitha Velusamy, Amit Singh Chhetri
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Patent number: 9678559Abstract: A decision engine executing on an electronic device may determine, using sensor data captured by multiple sensors of the device, whether a user is present in an environment that includes the device. If the user is determined to be present in the environment, the device may transition from a first state to a second state. The first state may be a first power state of the device in which the device is powered off or an idle or dormant state in which the device is powered on but a display of the device is powered off. Correspondingly, the second state may be a second power state of the device in which the device and the display are powered on and content is being rendered on the display. If the decision engine cannot make a determination based on the sensor data, a context engine may adjudicate the user presence determination.Type: GrantFiled: September 18, 2015Date of Patent: June 13, 2017Assignee: Amazon Technologies, Inc.Inventors: David William Devries, Stewart Robin Shearer, Amit Singh Chhetri, Serkan Hatipoglu, Omar Sze Leung, Michael Serge Devyver, Leo Benedict Baldwin, Noam Sorek
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Patent number: 9591404Abstract: Embodiments of systems and methods are described for determining weighting coefficients based at least in part on using convex optimization subject to one or more constraints to approximate a three-dimensional beampattern. In some implementations, the approximated three-dimensional beampattern comprises a main lobe that includes a look direction for which waveforms detected by a sensor array are not suppressed and a side lobe that includes other directions for which waveforms detected by the microphone array are suppressed. The one or more constraints can include a constraint that suppression of waveforms received by the sensor array from the side lobe are greater than a threshold. In some implementations, the threshold can be dependent on at least one of an angular direction of the waveform and a frequency of the waveform.Type: GrantFiled: September 27, 2013Date of Patent: March 7, 2017Assignee: Amazon Technologies, Inc.Inventor: Amit Singh Chhetri
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Patent number: 9521249Abstract: An echo path change detector may be used to control the rate of adaptation in an acoustic echo canceller. When echo path change is declared, the rate of adaptation may be increased. However, echo path change should not be declared in the presence of double talk, because rapid adaptation during double talk is undesirable. Accordingly, various features are disclosed for detecting echo path changes while avoiding the declaration of such changes in the presence of double talk.Type: GrantFiled: January 29, 2015Date of Patent: December 13, 2016Assignee: Amazon Technologies, Inc.Inventor: Amit Singh Chhetri
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Patent number: 9473646Abstract: An acoustic echo canceller (AEC) system may be configured to reset the coefficients of a transform equation when an estimated echo diverges from actual acoustic echo. Features are disclosed for determining when to reset the coefficients, and for enabling the reset operation to be performed reliably. Additional features are disclosed for detecting other signal conditions besides AEC divergence, for adjusting the rate at which the coefficients are adapted in response to such conditions, and for prioritizing between potentially incompatible adjustments.Type: GrantFiled: September 16, 2013Date of Patent: October 18, 2016Assignee: Amazon Technologies, Inc.Inventor: Amit Singh Chhetri
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Patent number: 9456276Abstract: An audio beamformer receives signals from microphones of an array and processes the signals to produce a directional audio signal that emphasizes sound from a selected direction. The beamformer is implemented using weights or other parameters that are calculated to account for effects upon the received audio signals by the surfaces upon which the microphones are positioned.Type: GrantFiled: September 30, 2014Date of Patent: September 27, 2016Assignee: Amazon Technologies, Inc.Inventor: Amit Singh Chhetri
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Patent number: 9432768Abstract: A wearable computer is configured to use beamforming techniques to isolate a user's speech from extraneous audio signals occurring within a physical environment. A microphone array of the wearable computer may generate audio signal data from an utterance from a user's mouth. A motion sensor(s) of the wearable computer may generate motion data from movement of the wearable computer. This motion data may be used to determine a direction vector pointing from the wearable computer to the user's mouth, and a beampattern may be defined that has a beampattern direction in substantial alignment with the determined direction vector to focus the microphone array on the user's mouth for speech isolation.Type: GrantFiled: March 28, 2014Date of Patent: August 30, 2016Assignee: Amazon Technologies, Inc.Inventors: Jeffrey Cornelius O'Neill, Amit Singh Chhetri, Philip Ryan Hilmes, Ramya Gopalan
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Patent number: 9432769Abstract: Embodiments of systems and methods are described for determining which of a plurality of beamformed audio signals to select for signal processing. In some embodiments, a plurality of audio input signals are received from a microphone array comprising a plurality of microphones. A plurality of beamformed audio signals are determined based on the plurality of input audio signals, the beamformed audio signals comprising a direction. A plurality of signal features may be determined for each beamformed audio signal. Smoothed features may be determined for each beamformed audio signal based on at least a portion of the plurality of signal features. The beamformed audio signal corresponding to the maximum smoothed feature may be selected for further processing.Type: GrantFiled: July 30, 2014Date of Patent: August 30, 2016Assignee: Amazon Technologies, Inc.Inventors: Shiva Sundaram, Amit Singh Chhetri, Ramya Gopalan, Philip Ryan Hilmes
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Patent number: 9390723Abstract: Features are disclosed for performing efficient dereverberation of speech signals captured with single- and multi-channel sensors in networked audio systems. Such features could be used in applications requiring automatic recognition of speech captured with sensors. Dereverberation is performed in the sub-band domain, and hence provides improved dereverberation performance in terms of signal quality, algorithmic delay, computational efficiency, and speed of convergence.Type: GrantFiled: December 11, 2014Date of Patent: July 12, 2016Inventors: John Walter McDonough, Jr., Wai Chung Chu, Amit Singh Chhetri, Robert Ayrapetian
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Patent number: 8983057Abstract: A step size controller may be used to control the rate of adaptation in an acoustic echo canceller. Step size control based on the values of adaptive coefficients (rather than, e.g., a fixed initial adaptation period) provides improved reliability and resistance to disruption. Accordingly, features are disclosed for controlling step size based on the values of adaptive coefficients.Type: GrantFiled: September 20, 2013Date of Patent: March 17, 2015Assignee: Amazon Technologies, Inc.Inventors: Hongyang Deng, Amit Singh Chhetri
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Patent number: 8953777Abstract: An echo path change detector may be used to control the rate of adaptation in an acoustic echo canceller. When echo path change is declared, the rate of adaptation may be increased. However, echo path change should not be declared in the presence of double talk, because rapid adaptation during double talk is undesirable. Accordingly, various features are disclosed for detecting echo path changes while avoiding the declaration of such changes in the presence of double talk.Type: GrantFiled: May 30, 2013Date of Patent: February 10, 2015Assignee: Amazon Technologies, Inc.Inventor: Amit Singh Chhetri
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Publication number: 20070280472Abstract: An acoustic echo cancellation technique. The present adaptive acoustic echo cancellation technique employs a plurality of acoustic echo cancellation filters which use different adaptation techniques which may employ different parameters such as step size, to improve both the adaptation algorithm convergence time and misadjustment over previously known acoustic echo cancellation techniques.Type: ApplicationFiled: May 30, 2006Publication date: December 6, 2007Applicant: Microsoft CorporationInventors: Jack W. Stokes III, Dinei A. Florencio, Amit Singh Chhetri