Method and system for evaluating the quality of a physiological signal
Inventors
PRIEM, Gurvan • BODINIER, Quentin
Assignees
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Publication Number
US-12343175-B2
Publication Date
2025-07-01
Expiration Date
Abstract
A method, intended for the evaluation of the quality of at least one periodic or quasi-periodic physiological signal, which includes the steps of: segmenting the physiological signal temporally into a plurality of signal segments; for each given signal segment, determining a distance representative of a shape difference between the given signal segment and at least one signal segment temporally offset relative to the given signal segment; and determining a quality index of the given signal segment according to the distance determined for the given signal segment.
Core Innovation
The invention evaluates the quality of a periodic or quasi-periodic physiological signal by temporally segmenting the physiological signal into a plurality of signal segments. Each signal segment has an identical temporal length that is higher than or equal to a predefined longest period of the physiological signal, and for each signal segment a distance representative of a shape difference is continuously determined between the signal segment and at least one signal segment temporally offset relative to the signal segment.
A quality index of each signal segment is determined according to the distance determined for each signal segment. The quality index of each signal segment is compared to a threshold based upon quality criteria, and each signal segment having a quality index less than the threshold is excluded. In described embodiments, the distance can be computed using a transformation function so that the distance representative of the shape difference is an Euclidean distance between transformed representations of the segments.
The disclosed approach further includes mapping the distance to a quality index, including a stated distance-to-quality mapping of q = 1/(1+d). In additional described embodiments, the method evaluates quality using simultaneously recorded sensor data to address motion artifacts, including motion-artifact handling by modifying a combined sliding distance matrix using a gyroscope sensor power.
Claims Coverage
The partial content provides two independent claims: one for a method and one for a system. Across these independent claims, the inventive content centers on fixed-length temporal segmentation, continuous shape-difference distance determination against temporally offset segments, converting distance to a per-segment quality index, comparing to a threshold, and excluding segments below the threshold.
Fixed-length temporal segmentation based on longest period
Segmenting a physiological signal temporally into a plurality of signal segments, each signal segment having an identical temporal length selected to be higher than or equal to a predefined longest period of the physiological signal.
Continuous shape-difference distance to temporally offset segments
For each signal segment, continuously determining a distance representative of a shape difference between each signal segment and at least one signal segment temporally offset relative to each signal segment.
Per-segment quality index from distance
Determining a quality index of each signal segment according to the distance determined for each signal segment.
Quality-threshold comparison and exclusion of low-quality segments
Comparing the quality index of each signal segment to a threshold based upon quality criteria; and excluding each signal segment having a quality index less than the threshold.
Acquisition and processing modules implementing segment-quality exclusion
Providing an acquisition module configured to acquire a physiological signal, and a processing module configured to segment the physiological signal, continuously determine a distance representative of a shape difference for each segment versus temporally offset segments, determine a quality index according to the distance, compare the quality index to a threshold based upon quality criteria, and exclude each segment having a quality index less than the threshold.
Device-level PPG multi-wavelength acquisition
Using at least two light sources emitting at two distinct wavelengths to acquire photoplethysmographic (PPG) signals from illuminated tissue, while segmenting each PPG signal temporally and determining a quality index for each segment based on computed shape-difference distance versus at least one temporally offset segment.
Simultaneous gyroscope data for motion-artifact quality evaluation
Including a gyroscope so that simultaneously recorded gyroscope data is used to evaluate the quality of the physiological signal and detect motion artifacts.
The independent claims cover, at the method and system levels, a pipeline that segments a physiological signal into fixed-length segments based on a longest period, computes a continuously updated shape-difference distance between each segment and temporally offset segments, derives a quality index from that distance, compares the quality index to a threshold, and excludes segments below the threshold. The partial content further indicates dependent claim refinements for PPG acquisition with distinct wavelengths and for motion-artifact handling using simultaneously recorded gyroscope data.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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