Spatiotemporal-based detection and correction of motion artifact for measurement of arterial pressure waveform
Inventors
Thanikachalam, Mohan • Upton, Emily • Aleiferis, Stamatios • Rajamanickam, Gokul Prasath
Assignees
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Publication Number
US-12599340-B2
Publication Date
2026-04-14
Expiration Date
Abstract
A method and system for spatiotemporal management of motion artifacts/blood pressure drifts in an arterial pressure waveform. The system includes an elastomeric sensor array in touch with a surface patch of skin over a superficial artery of a subject, an actuator mounted over the elastomeric sensor array, and a camera mounted on the actuator to capture image data that a controller processes. The controller measures the arterial pressure waveform having motion artifacts caused by elastomeric sensor array deformation on the skin over the artery in the pulsatile area and over the skin adjacent to the artery in the non-pulsatile area. Further, the controller determines spatiotemporal information of the motion artifact in the pulsatile and non-pulsatile areas, correcting the arterial pressure waveform by removing the motion artifact based on the spatiotemporal information to determine the physiological parameters.
Core Innovation
The invention relates to correction of motion artifacts affecting a physiological waveform, including an arterial pressure waveform, measured using a sensor array in contact with skin of a subject. The motion artifact is caused by movement of a body part of the subject or an external movement imparted to the subject, and affects deformation or movement of the sensor array over an artery in a pulsatile area and over skin adjacent to the artery in a non-pulsatile area in response to an external positive pressure being applied.
Motion-artifact information is determined separately for the pulsatile area and the non-pulsatile area, and the physiological waveform is corrected by removing or suppressing the motion artifact based on at least the motion-artifact information in the non-pulsatile area to produce a corrected physiological waveform. Physiological parameters of the subject are determined based on the corrected physiological waveform in which the motion artifact is suppressed based on at least the motion-artifact information in the non-pulsatile area.
The invention includes detecting a type of motion artifact present in the pulsatile area and the non-pulsatile area. The invention digitally separates the pulsatile area and the non-pulsatile area in the image data by estimating a displacement of the image data at each time point, determining a variance of a signal over time based on the displacement, and performing a temporal Fourier transform of the displacement of the image data at all locations based on the variance over time.
Areas with the transformed displacement that meet a predefined threshold are segmented into the pulsatile area, while areas that do not meet the predefined threshold are segmented into the non-pulsatile area. The invention further detects motion-artifact characteristics and can use artifact-flag logic to determine whether an artifact flag is raised and apply a correction technique based on the raised artifact flag and the detected type of motion artifact.
Claims Coverage
Independent claims are directed to correction of motion artifacts in a physiological waveform using image data and non-pulsatile-area-based suppression, and to digital separation of pulsatile and non-pulsatile regions by spatiotemporal processing. The inventive features include determining motion-artifact information in both pulsatile and non-pulsatile areas, suppressing artifacts in the physiological waveform using non-pulsatile-area information, and deriving physiological parameters from the corrected waveform; additional inventive features include detecting a type of motion artifact with artifact-flag logic and digitally separating pulsatile versus non-pulsatile areas using displacement, variance, and temporal Fourier thresholding.
Correcting a physiological waveform using non-pulsatile-area motion-artifact information
Receiving image data from a sensor array configured to be in contact with a skin of a subject; analyzing the image data to characterize a physiological waveform that includes motion artifact caused by movement of a body part of the subject or an external movement imparted to the subject; determining information relating to the motion artifact affecting the pulsatile area and the non-pulsatile area; correcting the physiological waveform by removing or suppressing the motion artifact based on at least the information relating to the motion artifact in the non-pulsatile area to produce a corrected physiological waveform; and determining physiological parameters of the subject based on the corrected physiological waveform.
Detecting a motion-artifact type and applying artifact-flag logic
Correcting the physiological waveform by detecting a type of motion artifact present in the pulsatile area and in the non-pulsatile area; detecting whether an artifact flag is raised responsive to detecting the type of motion; and applying a correction technique to remove the motion artifact from the physiological waveform based on at least the information, the raised artifact flag, and the type of the motion artifact present in the pulsatile area and in the non-pulsatile area.
System using a camera-captured sensor-array image to correct an arterial pressure waveform
A sensor array configured to be in contact with a surface patch of a skin of a subject, the system having a camera that captures image data of the sensor array; and a controller configured to measure an arterial pressure waveform based on the image data and determine information relating to the motion artifact affecting the pulsatile area and the non-pulsatile area; correct the arterial pressure waveform by removing the motion artifact based on the determined information; and determine physiological parameters based on the corrected arterial pressure waveform in which the motion artifact is suppressed based on at least the information relating to the motion artifact in the non-pulsatile area.
Digitally separating pulsatile and non-pulsatile areas using displacement variance and temporal Fourier thresholding
The controller is further configured to digitally separate the pulsatile area and the non-pulsatile area in the image data by estimating a displacement of the image data at each time point; determining a variance of a signal over time based on the displacement; performing a temporal Fourier transform of the displacement of the image data at all locations based on the variance of the signal over time; determining areas with the transformed displacement that meet a predefined threshold; and segmenting the determined areas with the transformed displacement that meet the predefined threshold into the pulsatile area and the areas with the transformed displacement that do not meet the predefined threshold into the non-pulsatile area.
Detecting motion-artifact characteristics in a non-pulsatile area using a pulse-free reference signal
The detecting of the characteristic of the motion artifact in the non-pulsatile area comprises determining a plurality of parameters associated with the non-pulsatile area; determining at least one reference region in the image data based on the plurality of parameters associated with the non-pulsatile area; filtering out a residual pulsatile signal from at least one reference region to produce a pulse-free reference signal; and detecting the characteristic of the motion artifact in the non-pulsatile area based on the pulse-free reference signal from at least one reference region.
Template-based pulsatile-area artifact flagging based on morphology changes
Detecting a motion artifact characteristic in the pulsatile area by matching a beat template to changes in the morphology of an arterial pressure waveform that trigger a high-frequency artifact flag.
Detecting type-of-motion artifacts and applying a correction technique based on artifact flag and type
Correcting the arterial pressure waveform comprises detecting a type of motion artifact present in the pulsatile area and the non-pulsatile area; detecting whether an artifact flag is raised; and applying a correction technique to remove the motion artifact from the arterial pressure waveform based on at least the information, the raised artifact flag, and the type of motion artifact in the pulsatile area and the non-pulsatile area.
Across the independent claim set, the core claim coverage centers on suppressing motion artifacts in a physiological waveform by determining motion-artifact information in both pulsatile and non-pulsatile areas and applying correction based on at least the non-pulsatile-area information. Additional independent-claim coverage includes digitally separating pulsatile versus non-pulsatile regions using estimated displacement, variance over time, and a temporal Fourier transform with predefined thresholding, and implementing correction logic based on detected motion-artifact type and whether an artifact flag is raised.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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