Analog Devices,inc.

Analog Devices Global Unlimited Company

Sefa Demirtas

Nicolas Le Dortz

Charles Mathy

Robert W Adams

Jeffrey G Bernstein

Tao Yu

Atulya Yellepeddi

Brian C Donnelly

Jonathan Ephraim David Hurwitz

Jochen Schmitt

Arthur Joseph Kalb

Boris Lerner

Harvey Weinberg

Yogesh Jayaraman Sharma

Erik D Barnes

Tony Joseph Akl

Bin Huo

Jonathan Ari Goldberg

Paul R Blanchard

Jason D King

Dhruvesh Gajaria

James Noraky

An image processing system having on-the-fly calibration uses the placement of the imaging sensor and the light source for calibration. The placement of the imaging sensor and light source with respect to each other affect the amount of signal received by a pixel as a function of distance to a selected object. For example, an obstruction can block the light emitter, and as the obstruction is positioned an increasing distance away from the light emitter, the signal level increases as light rays leave the light emitters, bounce off the obstruction and are received by the imaging sensor. The system includes a light source configured to emit light, and an image sensor to collect incoming signals including reflected light, and a processor to determine a distance measurement at each of the pixels and calibrate the system.

Built-in calibration of time-of-flight depth imaging systems

Depth imagers can implement time-of-flight operations to measure depth or distance of objects. A depth imager can emit light onto a scene and sense light reflected back from the objects in the scene using an array of sensors. Timing of the reflected light hitting the array of sensors gives information about the depth or distance of objects in the scene. In some cases, corrupting light that is outside of a field of view of a pixel in the array of sensors can hit the pixel due to internal scattering or internal reflections occurring in the depth imager. The corrupting light can corrupt the depth or distance measurement. To address this problem, an improved depth imager can isolate and measure the corrupting light due to internal scattering or internal reflections occurring in the depth imager, and systematically remove the measured corrupting light from the depth or distance measurement.

Measuring and removing the corruption of time-of-flight depth images due to internal scattering

Aspects of the embodiments are directed to passive depth determination. Initially, a high power depth map of a scene can be created. An object in the scene can be identified, such as a rigid body or other object or portion of an object. A series of lower power or RGB images can be captured. The object can be located in one or more of the lower power or RGB images. A change in the position of an object, represented by a set of pixels, can be determined. From the change in position of the object, a new depth of the object can be extrapolated. The extrapolated depth of the object can be used to update the high power depth map.

Reducing power consumption for time-of-flight depth imaging

Embodiments of the present disclosure provide mechanisms for measuring currents flowing in one or more conductor wires. The mechanisms are based on using magnetic sensor pairs arranged within a housing with an opening for the wires, where each magnetic sensor pair can generate a pair of signals indicative of magnetic fields in two different directions. The outputs of the sensor pairs can be used to derive a measure of current(s) flowing through the one or more wires. The use of magnetic sensor pairs that can measure magnetic field in two different directions may enable simultaneous current measurement in multiple wires placed within the opening, improve accuracy of current measurements while relaxing requirements for precise control of the placement of the wire(s), reduce the impact of stray magnetic interference, and enable both AC and DC measurements.

Current measurement using magnetic sensors and contour intervals

Aspects of the embodiments are directed to methods and imaging systems. The imaging systems can be configured to sense, by an light sensor of the imaging system, light received during a time period, process the light received by the light sensor, identify an available measurement period for the imaging system within the time period based on the processed light, and transmit and receive light during a corresponding measurement period in one or more subsequent time periods.

Interference handling in time-of-flight depth sensing

Activity monitors and smart watches utilizing optical measurements are becoming widely popular, and users expect to get an increasingly accurate estimate of their heart rate (HR) from these devices. These devices are equipped with a light source and an optical sensor which enable estimation of HR using a technique called photoplethysmography (PPG). One of the main challenges of HR estimation using PPG is the coupling of motion into the optical PPG signal when the user is moving randomly or exercising. The present disclosure describes a computationally feasible and fast HR estimation algorithm to be executed at instances of little or no motion. Resulting HR readings may be useful on their own, or be provided to systems that monitor HR continuously to prevent the problem of such systems being locked on an incorrect HR for long periods of time. Implementing techniques described herein leads to more accurate HR measurements.

On-demand heart rate estimation based on optical measurements

Embodiments of the present disclosure provide mechanisms that enable designing an FIR filter that would have a guaranteed globally optimal magnitude response in terms of the minimax optimality criterion given a desired weight on the error in the stopband versus the passband. Design of such a filter is based on a theorem ('characterization theorem') that provides an approach for characterizing the global minimax optimality of a given FIR filter h[n], n=0, 1, . . . , N, where optimality is evaluated with respect to a magnitude response of this filter, |H(e)|, as compared to the desired filter response, D(&#x3c9;), which is unity in the passband and zero in the stopband. The characterization theorem enables characterizing optimality for both real-valued and complex-valued filter coefficients, and does not require any symmetry in the coefficients, thus being applicable to all non-linear phase FIR filters.

Designing FIR filters with globally minimax-optimal magnitude response

Heart rate monitors are plagued by noisy photoplethysmography (PPG) data, which makes it difficult for the monitors to output a consistently accurate heart rate reading. Noise is often caused by motion. Using known methods for processing accelerometer readings that measure movement to filter out some of this noise may help, but not always. The present disclosure describes an improved front-end technique (time-domain interference removal) based on using adaptive linear prediction on accelerometer data to generate filters for filtering the PPG signal prior to tracking the frequency of the heartbeat (heart rate). The present disclosure also describes an improved back-end technique based on steering the frequency of a resonant filter in order to track the heartbeat. Implementing one or both of these techniques leads to more accurate heart rate measurements.

Time-domain interference removal for heart rate measurements

Tracking mechanism for heart rate measurements

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Malden, MA, United States of America

Sefa Demirtas