Abstract: A method and a system for determining an in vivo transit distance and a corresponding transit time for an arterial pulse. An example system comprises a radar receiver connected to a processor to perform time-resolved measurements of reflections of wave pulses and to spectrally filter the reflections to select spectral components associated with the arterial pulse. The resulting signal samples are then organized into groups corresponding to different wave pulses, and the groups are processed to identify samples corresponding to a first arterial pulse point and a second arterial pulse point on the body of a subject, and the identified samples are further processed to determine the in vivo transit distance and the corresponding transit time for the arterial pulse. In some embodiments, a collection of arterial pulse points detected by the measurements may be mapped onto a reference constellation for a more-accurate determination of the in vivo transit distance.

Abstract: Various sensing systems may benefit from appropriate handling of signal to noise ratios. For example, detecting and measuring physiological signals may benefit from a phasor approach to signal to noise ratio measurement evaluation. A method can include obtaining a plurality of observations of a target volume. The method can also include determining a weight for each observation of the plurality of observations of the volume. The weight can be based on a change in phasor characteristics of the observation. The method can further include combining the plurality of observations based on the weight. The method can additionally include identifying a physiological signal based on the combined observations.

Abstract: A method, apparatus and computer program product are provided in order to generate a visual indication to a user of a point of interest outside of the user's view. In the context of a method, identifying a point of interest outside of a user's view is identified during display of an image in a first orientation. The method also includes causing at least a portion of the image to be repositioned, such as by being tilted, to provide a visual indication to the user of a point of interest outside of the user's view. After repositioning at least the portion of the image, the method further includes causing at least the portion of the image to return to the first orientation.

Abstract: Methods, systems, and computer-readable media for synchronizing physiological signals collected from two or more physiological sensors are provided. Examples of physiological signals may include respiration, heartbeat, electroencephalogram, and gastrointestinal signals.

Abstract: A method, apparatus and computer program product are provided for determining an intimate activity has occurred based on data collected with a radar detection device. Data relating to sleep patterns, such as of a sleep study participant, may be collected with a radar detection device in close proximity to a bed or other reference point. The data may be processed to determine occurrence of intimate activities, based on detected movements and/or positions of body profiles relative to each other and/or to a common reference point. The data corresponding to intimate activities may therefore be appropriately processed, such as by being excluded from the sleep record data to provide privacy to a user.

Abstract: A method, apparatus and computer program product are provided for determining stress recovery based on chest and abdominal breathing information from a detection device such as a radar detection device. Stress recovery may be determined by monitoring a phase difference between chest and abdominal breathing relative to a stress indicator, such as heart rate variability. Target respiration information may be determined and/or calibrated for the particular user based on the stress indicator. Breathing exercises may be provided to the user to assist in steadying their breathing and recovering from stress. Based on the monitoring of the chest and abdominal breathing information, efficacy of the breathing exercise may then be determined based on whether the user is recovering from stress, and further feedback may be provided to the user.

Abstract: A method comprising: at a processor, determining an in vivo transit distance for an arterial pulse between a first arterial pulse point and a second arterial pulse point using a first distance measured to the first arterial pulse point and a second distance measured to a second arterial pulse point; and at the processor, determining a transit time for an arterial pulse between the first arterial pulse point and the second arterial pulse point, based on one or more transmitted detecting and ranging wave pulses reflected from the first arterial pulse point and from one or more transmitted detecting and ranging wave pulses reflected from the second arterial pulse point.

Abstract: Various sensing systems may benefit from appropriate handling of signal to noise ratios. For example, detecting and measuring physiological signals may benefit from a phasor approach to signal to noise ratio measurement evaluation. A method can include obtaining a plurality of observations of a target volume. The method can also include determining a weight for each observation of the plurality of observations of the volume. The weight can be based on a change in phasor characteristics of the observation. The method can further include combining the plurality of observations based on the weight. The method can additionally include identifying a physiological signal based on the combined observations.

Abstract: A method of determining a user location comprises: calculating a horizontal velocity and direction of horizontal movement of a mobile device in communication with at least one wireless access point, calculating an observed Doppler shift in a signal transmitted between the mobile device and the at least one wireless access point, calculating an expected Doppler shift in the transmitted signal based on a carrier frequency, the horizontal velocity and direction of horizontal movement, and determining a vertical position of the mobile device based on the expected Doppler shift and the observed Doppler shift. A mobile device, apparatus and positioning system for performing the method are also provided.

Abstract: A method, apparatus and computer program product are provided in order to generate a visual indication to a user of a point of interest outside of the user's view. In the context of a method, identifying a point of interest outside of a user's view is identified during display of an image in a first orientation. The method also includes causing at least a portion of the image to be repositioned, such as by being tilted, to provide a visual indication to the user of a point of interest outside of the user's view. After repositioning at least the portion of the image, the method further includes causing at least the portion of the image to return to the first orientation.

Abstract: Systems and techniques for in-phase/quadrature estimation are described. As data frames are received at a wireless networking direct-conversion receiver, preambles of the data frames are examined to identify frequency-independent subcarriers. Preamble-based estimation is used to estimate in-phase/quadrature imbalance for frequency-independent subcarriers and blind estimation is used to estimate in-phase/quadrature imbalance for frequency-dependent subcarriers. The estimation may be performed continuously and refined as new frames are received. At appropriate intervals, compensation is performed using current imbalance estimates.

Abstract: Systems and techniques for in-phase/quadrature estimation are described. Reference signals are configured and used to perform in-phase and quadrature estimation of a transmitter of a transceiver. Compensation is then performed on the transmitter and the fully-compensated transmitter is used to provide reference signals for in-phase and quadrature estimation of the receiver, and receiver compensation is performed.

Abstract: Systems and techniques for in-phase/quadrature estimation are described. As data frames are received at a wireless networking direct-conversion receiver, preambles of the data frames are examined to identify frequency-independent subcarriers. Preamble-based estimation is used to estimate in-phase/quadrature imbalance for frequency-independent subcarriers and blind estimation is used to estimate in-phase/quadrature imbalance for frequency-dependent subcarriers. The estimation may be performed continuously and refined as new frames are received. At appropriate intervals, compensation is performed using current imbalance estimates.

Abstract: A known sequence of symbols is located within a transmitted sequence of symbols by estimating the phase differences between offset symbols within a portion or more of the transmitted sequence, estimating the phase differences between offset symbols in the known sequence, and determining that the symbols within the portion or more of the transmitted sequence are the known sequence if the phase difference estimates determined from the symbols within the portion or more of the transmitted sequence are substantially equal to the phase difference estimates determined from the known sequence.