Patents by Inventor Ravi Narasimhan

Ravi Narasimhan 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).

  • Patent number: 10874307
    Abstract: An example of a digital artery blood pressure monitor may include a tactile sensor array disposed on an inner surface of a cuff, the tactile sensor array including a plurality of capacitive sensors to detect pressure changes within a digital artery of a finger due to blood flow, where the pressure changes cause changes to capacitance values of one or more capacitive sensors of the tactile sensor array, and control circuitry coupled to the tactile sensor array to receive the capacitance values from the tactile sensor array, and determine a blood pressure based on the capacitance values.
    Type: Grant
    Filed: January 24, 2017
    Date of Patent: December 29, 2020
    Assignee: Verily Life Sciences LLC
    Inventors: Ravi Narasimhan, Tushar Parlikar, Todd Whitehurst
  • Publication number: 20200337571
    Abstract: An example of a digital artery blood pressure monitor may include a tactile sensor array disposed on an inner surface of a cuff, the tactile sensor array including a plurality of capacitive sensors to detect pressure changes within a digital artery of a finger due to blood flow, where the pressure changes cause changes to capacitance values of one or more capacitive sensors of the tactile sensor array, and control circuitry coupled to the tactile sensor array to receive the capacitance values from the tactile sensor array, and determine a blood pressure based on the capacitance values.
    Type: Application
    Filed: July 8, 2020
    Publication date: October 29, 2020
    Inventors: Ravi Narasimhan, Tushar Parlikar, Todd Whitehurst
  • Patent number: 10779738
    Abstract: Wrist-worn devices and related methods measure a pulse transit time non-invasively and calculate a blood pressure value using the pulse transit time. A wrist-worn device include a wrist-worn elongate band, at least four EKG or ICG electrodes coupled to the wrist-worn device for detecting a ventricular ejection of a heart, a photo-plethysmogram (PPG) sensor coupled to the wrist-worn device for detecting arrival of a blood pressure pulse at the user's wrist, and a controller configured to calculate a pulse transit time (PTT) for the blood pressure pulse. The controller calculates one or more blood pressure values for the user based on the PTT.
    Type: Grant
    Filed: August 18, 2017
    Date of Patent: September 22, 2020
    Inventors: Thomas J. Sullivan, Wren Nancy Dougherty, Richard C. Kimoto, Erno Klaassen, Ravi Narasimhan, Stephen J. Waydo, Todd K. Whitehurst, Derek Park-Shing Young, Santiago Quijano, Zijing Zeng
  • Patent number: 10772512
    Abstract: The present invention provides non-invasive devices, methods, and systems for determining a pressure of blood within a cardiovascular system of a user, the cardiovascular system including a heart and the user having a wrist covered by skin. More particularly, the present invention discloses a variety of wrist-worn devices having a variety of sensors configured to non-invasively engage the skin on the wrist of the user for sensing a variety of user signals from the cardiovascular system of the user. Generally, approaches disclosed herein may passively track blood pressure values without any interaction required on the part of the user or may allow for on demand or point measurements of blood pressure values by having a user actively interact with the sensors of the wrist-worn device.
    Type: Grant
    Filed: August 18, 2017
    Date of Patent: September 15, 2020
    Inventors: Erno H. Klaassen, Wren Nancy Dougherty, Richard C. Kimoto, Ravi Narasimhan, Thomas J. Sullivan, Stephen J. Waydo, Todd K. Whitehurst, Santiago Quijano, Derek Park-Shing Young, Zijing Zeng
  • Patent number: 10719574
    Abstract: A method and system for calibrating a wireless sensor device are disclosed. In a first aspect, the method comprises determining a vertical calibration vector and determining a rotation matrix using the vertical calibration vector to line up native axes of the wireless sensor device with body axes. In a second aspect, a wireless sensor device comprises a processor and a memory device coupled to the processor, wherein the memory device includes an application that, when executed by the processor, causes the processor to determine a vertical calibration vector and to determine a rotation matrix using the vertical calibration vector to line up native axes of the wireless sensor device with body axes.
    Type: Grant
    Filed: January 8, 2018
    Date of Patent: July 21, 2020
    Assignee: Vital Connect, Inc.
    Inventors: Alexander Chan, Nima Ferdosi, Ravi Narasimhan
  • Patent number: 10702171
    Abstract: The present invention generally relates to blood pressure monitoring. In some embodiments, methods and devices of measuring a mean arterial pressure are provided and/or monitoring blood pressure changes. A wrist-worn device may include a plurality of sensors backed by a plurality of actuators. Subsets of the plurality of sensors may be selectively actuateable against a wrist of a user using one or more of the plurality of actuators. A preferred sensor and location may be identified based on pressure signals received from each of the sensors. In some embodiments, devices may use a fluid bladder coupled with piezoelectric film sensors. A fluid bladder pressure sensor may be used to calibrate the piezoelectric film signal to provide a static and dynamic pressure reading. In yet another embodiment, a mean arterial pressure may be calculated by processing a swept pressure signal obtained as a sensor is swept through different heights.
    Type: Grant
    Filed: September 8, 2015
    Date of Patent: July 7, 2020
    Inventors: Ravi Narasimhan, Zijing Zeng, Richard C. Kimoto, Erno Klaassen, Thomas J. Sullivan, Derek Park-Shing Young, Todd K. Whitehurst
  • Patent number: 10687757
    Abstract: A method and system for determining psychological acute stress are disclosed. In a first aspect, the method comprises detecting a physiological signal using a wireless sensor device, determining a stress feature using a normalized heart rate and a plurality of heart rate variability (HRV) features, wherein the normalized heart rate and the plurality of heart rate variability features are calculated using the detected physiological signal, and determining a stress level using the stress feature to determine the psychological acute stress. In a second aspect, the system comprises a wireless sensor device that includes a processor and a memory device coupled to the processor, wherein the memory device stores an application which, when executed by the processor, causes the wireless sensor device to carry out the steps of the method.
    Type: Grant
    Filed: May 22, 2018
    Date of Patent: June 23, 2020
    Assignee: Vital Connect, Inc.
    Inventors: Alexander Chan, Ravi Narasimhan, Nandakumar Selvaraj, Toai Doan
  • Patent number: 10667713
    Abstract: A method and system for R-R interval measurement of a user are disclosed. In a first aspect, the method comprises detecting an electrocardiogram (ECG) signal of the user. The method includes performing QRS peak detection on the ECG signal to obtain a low resolution peak and searching near the low resolution peak for a high resolution peak. The method includes calculating the R-R interval measurement based upon the high resolution peak. In a second aspect, a wireless sensor device comprises a processor and a memory device coupled to the processor, wherein the memory device includes an application that, when executed by the processor, causes the processor to carry out the steps of the method.
    Type: Grant
    Filed: November 8, 2017
    Date of Patent: June 2, 2020
    Assignee: Vital Connect, Inc.
    Inventors: Yun Yang, Ravi Narasimhan, Nima Ferdosi
  • Patent number: 10617325
    Abstract: A method and system for measuring respiratory rate are disclosed. In a first aspect, the method comprises measuring at least one respiration signal and filtering the respiration signal using a lowpass filter. The method includes peak-picking the respiration signal to determine the respiratory rate and determining a quality metric of the respiratory rate. In a second aspect, the system comprises a wireless sensor device coupled to a user via at least one electrode, wherein the wireless sensor device includes a processor and a memory device coupled to the processor, wherein the memory device stores an application which, when executed by the processor, causes the processor to carry out the steps of the method.
    Type: Grant
    Filed: November 30, 2017
    Date of Patent: April 14, 2020
    Assignee: Vital Connect, Inc.
    Inventors: Alexander Chan, Ravi Narasimhan
  • Publication number: 20200046231
    Abstract: A method and system for contextual heart rate monitoring are disclosed. In a first aspect, the method comprises calculating a heart rate using a detected ECG signal and detecting an activity level. In a second aspect, the system comprises a wireless sensor device coupled to a user via at least one electrode, wherein the wireless sensor device includes a processor and a memory device coupled to the processor, wherein the memory device stores an application which, when executed by the processor, causes the processor to calculate a heart rate using a detected ECG signal and to detect an activity level.
    Type: Application
    Filed: October 18, 2019
    Publication date: February 13, 2020
    Inventors: Nima FERDOSI, Ravi NARASIMHAN, ALEXANDER CHAN
  • Patent number: 10517489
    Abstract: Wrist-worn devices and related methods measure a pulse transit time non-invasively and calculate a blood pressure value using the pulse transit time. A wrist-worn device includes an accelerometer, a photo-lethysmogram (PPG) or a pulse pressure sensor, and a controller. The PPG or the pulse pressure sensor coupled to the wrist-worn device for detecting an arrival of a blood pressure pulse at the user's wrist. The controller is configured to process output signals from the accelerometer to detect when the blood pressure pulse is propagated from the left ventricle of the user's heart, process a signal from the PPG or the pulse pressure sensor to detect when the blood pressure pulse arrives at the wrist, calculate a pulse transit time (PTT) for propagation of the blood pressure pulse from the left ventricle to the wrist, and generate one or more blood pressure values for the user based on the PTT.
    Type: Grant
    Filed: September 8, 2015
    Date of Patent: December 31, 2019
    Inventors: Ravi Narasimhan, Richard C. Kimoto, Thomas J. Sullivan, Todd K. Whitehurst, Derek Park-shing Young, Zijing Zeng, Erno Klaassen
  • Publication number: 20190336010
    Abstract: A method and system for determining a respiratory rate of a user using an electrocardiogram (ECG) segment of the user are disclosed. The method comprises decomposing the ECG segment into a plurality of functions and evaluating the plurality of functions to choose one of the plurality of functions based on a respiratory band power. The method includes determining the respiratory rate using the one of the plurality of functions and a domain detection.
    Type: Application
    Filed: July 19, 2019
    Publication date: November 7, 2019
    Inventors: Nandakumar Selvaraj, Ravi Narasimhan
  • Patent number: 10448849
    Abstract: A method and system for contextual heart rate monitoring are disclosed. In a first aspect, the method comprises calculating a heart rate using a detected ECG signal and detecting an activity level. In a second aspect, the system comprises a wireless sensor device coupled to a user via at least one electrode, wherein the wireless sensor device includes a processor and a memory device coupled to the processor, wherein the memory device stores an application which, when executed by the processor, causes the processor to calculate a heart rate using a detected ECG signal and to detect an activity level.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: October 22, 2019
    Assignee: Vital Connect, Inc.
    Inventors: Nima Ferdosi, Ravi Narasimhan, Alexander Chan
  • Patent number: 10433781
    Abstract: A method and system for measuring psychological stress disclosed. In a first aspect, the method comprises determining R-R intervals from an electrocardiogram (ECG) to calculate a standard deviation of the R-R intervals (SDNN) and determining a stress feature (SF) using the SDNN. In response to reaching a threshold, the method includes performing adaptation to update a probability mass function (PMF). The method includes determining a stress level (SL) using the SF and the updated PMF to continuously measure the psychological stress. In a second aspect, the system comprises a wireless sensor device coupled to a user via at least one electrode, wherein the wireless sensor device includes a processor and a memory device coupled to the processor, wherein the memory device stores an application which, when executed by the processor, causes the processor to carry out the steps of the method.
    Type: Grant
    Filed: November 30, 2017
    Date of Patent: October 8, 2019
    Assignee: VITAL CONNECT, INC.
    Inventors: Alexander Chan, Ravi Narasimhan
  • Patent number: 10422814
    Abstract: A method and system for fall detection using machine learning are disclosed. The method comprises detecting at least one signal by a wireless sensor device and calculating a plurality of features from the at least one detected signal. The method includes training a machine learning unit of the wireless sensor device using the features to create a fall classification and a non-fall classification for the fall detection. The system includes a sensor to detect at least one signal, a processor coupled to the sensor, and a memory device coupled to the processor, wherein the memory device includes an application that, when executed by the processor, causes the processor to calculate a plurality of features from the at least one detected signal and to train a machine learning unit of the wireless sensor device using the features to create a fall classification and a non-fall classification for the fall detection.
    Type: Grant
    Filed: July 18, 2013
    Date of Patent: September 24, 2019
    Assignee: Vital Connect, Inc.
    Inventors: Alexander Chan, Nima Ferdosi, Ravi Narasimhan
  • Patent number: 10383562
    Abstract: A method and system for measuring psychological stress disclosed. In a first aspect, the method comprises determining R-R intervals from an electrocardiogram (ECG) to calculate a standard deviation of the R-R intervals (SDNN) and determining a stress feature (SF) using the SDNN. In response to reaching a threshold, the method includes performing adaptation to update a probability mass function (PMF). The method includes determining a stress level (SL) using the SF and the updated PMF to continuously measure the psychological stress. In a second aspect, the system comprises a wireless sensor device coupled to a user via at least one electrode, wherein the wireless sensor device includes a processor and a memory device coupled to the processor, wherein the memory device stores an application which, when executed by the processor, causes the processor to carry out the steps of the method.
    Type: Grant
    Filed: November 30, 2017
    Date of Patent: August 20, 2019
    Assignee: Vital Connect, Inc.
    Inventors: Alexander Chan, Ravi Narasimhan
  • Patent number: 10357163
    Abstract: A method and system for determining a respiratory rate of a user using an electrocardiogram (ECG) segment of the user are disclosed. The method comprises decomposing the ECG segment into a plurality of functions and evaluating the plurality of functions to choose one of the plurality of functions based on a respiratory band power. The method includes determining the respiratory rate using the one of the plurality of functions and a domain detection.
    Type: Grant
    Filed: June 1, 2012
    Date of Patent: July 23, 2019
    Assignee: VITAL CONNECT, INC.
    Inventors: Nandakumar Selvaraj, Ravi Narasimhan
  • Publication number: 20190183425
    Abstract: A method and system for low-distortion denoising of an ECG signal are disclosed. The method comprises determining at least one beat of the ECG signal for denoising using a beat selection logic and denoising the at least one beat using at least one ensemble averaging filter. The system includes a sensor to detect the ECG signal, a processor coupled to the sensor, wherein the processor includes a beat selection logic unit, and a memory device coupled to the processor, wherein the memory device includes an application that, when executed by the processor, causes the processor to determine at least one beat of the ECG signal for denoising using a beat selection logic and to denoise the at least one beat using at least one ensemble averaging filter.
    Type: Application
    Filed: February 26, 2019
    Publication date: June 20, 2019
    Inventors: Nima FERDOSI, Ravi NARASIMHAN
  • Patent number: 10324109
    Abstract: A method and wireless sensor device for determining a time period a person is in bed. In one aspect, a method includes utilizing a wireless sensor device to obtain a plurality of acceleration samples in relation to at least one axis associated with a person's body over a predetermined time window. The method also includes calculating a polar angle for each acceleration sample within the predetermined time window. The method also includes calculating a fraction of an amount of time within the predetermined time window that the polar angle is greater than an angle threshold that indicates that the person is lying down, where if the fraction is greater than a predetermined threshold, the predetermined time window is marked as a period the person is lying down.
    Type: Grant
    Filed: September 15, 2016
    Date of Patent: June 18, 2019
    Assignee: VITAL CONNECT, INC.
    Inventors: Alexander Chan, Ravi Narasimhan
  • Patent number: 10317427
    Abstract: A method and system for calibrating a wireless sensor device are disclosed. In a first aspect, the method comprises determining a vertical calibration vector and determining a rotation matrix using the vertical calibration vector to line up native axes of the wireless sensor device with body axes. In a second aspect, a wireless sensor device comprises a processor and a memory device coupled to the processor, wherein the memory device includes an application that, when executed by the processor, causes the processor to determine a vertical calibration vector and to determine a rotation matrix using the vertical calibration vector to line up native axes of the wireless sensor device with body axes.
    Type: Grant
    Filed: March 15, 2017
    Date of Patent: June 11, 2019
    Assignee: VITAL CONNECT, INC.
    Inventors: Alexander Chan, Nima Ferdosi, Ravi Narasimhan