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Researchers Submit Patent Application, "Physiological Signal Quality Classification for Ambulatory Monitoring", for Approval

February 12, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors Fu, Yongji (Cary, NC); Yang, Te-Chung Isaac (Aliso Viejo, CA), filed on September 20, 2013, was made available online on January 30, 2014.

The patent's assignee is Sharp Laboratories of America, Inc.

News editors obtained the following quote from the background information supplied by the inventors: "The present invention relates to ambulatory monitoring and, more particularly, to physiological signal quality classification methods and systems designed to improve ambulatory monitoring.

"Ambulatory monitoring of the physiological state of people who suffer from chronic diseases is an important aspect of chronic disease management. By way of example, ambulatory monitoring is in widespread use managing chronic diseases such as asthma and in elder care.

"Ambulatory monitoring is often performed using wearable devices that acquire and analyze physiological signals, such as heart and lung sounds, as people go about their daily lives. These signals are not always reliable. For example, a signal may be too noisy when a person speaks, or is in motion, or is in an environment with high background noise. Moreover, a signal may be too weak when a person does not place a sensor of the device at the proper body location or when an air chamber of the sensor is not fully sealed. When a signal is too noisy or too weak, confidence in physiological data extracted from the signal, such as the patient's heart rate, may be very low.

"Physiological data extracted from an unreliable physiological signal can have serious adverse consequences on patient health. For example, such physiological data can lead a patient or his or her clinician to improperly interpret the patient's physiological state and cause the patient to undergo treatment that is not medically indicated or forego treatment that is medically indicated."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "The present invention provides physiological signal quality classification methods and systems designed to improve ambulatory monitoring. The present invention, generally speaking, classifies physiological signals as good, noisy or weak based on signal properties. Once classified, signals are processed differently depending on their classification to avoid extracting unreliable physiological data and to induce action to improve signal quality. For example, where a signal is good, physiological data may be extracted from the signal and displayed to a person being monitored. Where a signal is noisy, a noisy signal notification may be displayed to the person in lieu of extracted physiological data. Where a signal is weak, a weak signal notification may be displayed to the person in lieu of extracted physiological data. Moreover, a noisy or weak signal notification displayed to a person being monitored may be accompanied by a corrective action recommendation, such as 'move to quieter environment' for a noisy signal or 'check body placement of sensor' for a weak signal.

"In one aspect of the invention, a physiological signal processing method for an ambulatory monitoring system comprises the steps of comparing by the system one or more properties of a physiological signal with one or more distinguishing properties of good, noisy and weak signals; classifying by the system the signal as one of good, noisy or weak based on the comparison; and processing by the system the signal in accordance with the classification.

"In some embodiments, the method further comprises the steps of extracting by the system an envelope for the signal; and generating by the system using the envelope an autocorrelation result for the signal, wherein the comparison is between one or more properties of the autocorrelation result and one or more distinguishing properties of good, noisy and weak signals.

"In some embodiments, the distinguishing properties comprise central peak width.

"In some embodiments, the distinguishing properties comprise non-central peak width.

"In some embodiments, the classifying step comprises classifying the signal as good based at least in part on a determination that a central peak of the signal has a width between a low central peak width threshold and a high central peak width threshold and a determination that a non-central peak of the signal has a width above a non-central peak width threshold.

"In some embodiments, the classifying step comprises classifying the signal as noisy based at least in part on a determination that a central peak of the signal has a width above a high central peak width threshold.

"In some embodiments, the classifying step comprises classifying the signal as weak based at least in part on a determination that a central peak of the signal has a width below a low central peak width threshold.

"In some embodiments, the classifying step comprises classifying the signal as weak based at least in part on a determination that no non-central peak of the signal has a width above a non-central peak width threshold.

"In some embodiments, the processing step comprises extracting physiological data from the signal in response to classifying the signal as good, and outputting the physiological data.

"In some embodiments, the processing step comprises generating a noisy signal notification in response to classifying the signal as noisy, and outputting the noisy signal notification.

"In some embodiments, the processing step comprises generating a weak signal notification in response to classifying the signal as weak, and outputting the weak signal notification.

"In another aspect of the invention, an ambulatory monitoring system comprises a transducer; and a signal processor communicatively coupled with the transducer, wherein under control of the signal processor the system compares one or more properties of a physiological signal detected by the transducer with one or more distinguishing properties of good, noisy and weak signals, classifies the signal as one of good, noisy or weak based on the comparison, and processes the signal in accordance with the classification.

"In some embodiments, under control of the signal processor the system extracts an envelope for the signal, and generates using the envelope an autocorrelation result for the signal, wherein the comparison is between one or more properties of the autocorrelation result and one or more distinguishing properties of good, noisy and weak signals.

"In some embodiments, under control of the signal processor the system classifies the signal as good based at least in part on a determination that a central peak of the signal has a width between a low central peak width threshold and a high central peak width threshold and a determination that a non-central peak of the signal has a width above a non-central peak width threshold.

"In some embodiments, under control of the signal processor the system classifies the signal as noisy based at least in part on a determination that a central peak of the signal has a width above a high central peak width threshold.

"In some embodiments, under control of the signal processor the system classifies the signal as weak based at least in part on a determination that a central peak of the signal has a width below a low central peak width threshold.

"In some embodiments, under control of the signal processor the system classifies the signal as weak based at least in part on a determination that no non-central peak of the signal has a width above a non-central peak width threshold.

"In yet another aspect of the invention, an ambulatory monitoring system comprises a transducer; and a signal processor communicatively coupled with the transducer, wherein under control of the signal processor the system compares signal peak widths of an autocorrelation result of a physiological signal generated by the transducer with predetermined signal peak width thresholds distinguishing a plurality of signal types, classifies the signal into one of the signal types based on the comparison, and processes the signal in accordance with the classification.

"In some embodiments, the plurality of signal types comprise at least two of good, noisy and weak.

"In some embodiments, the signal peak widths of the autocorrelation result comprise a central peak width and a non-central peak width.

"In some embodiments, under control of the signal processor the system classifies the signal as good based at least in part on a determination that a central peak width of the signal is between a low central peak width threshold and a high central peak width threshold and a determination that a non-central peak width of the signal is above a non-central peak width threshold.

"In some embodiments, under control of the signal processor the system classifies the signal as noisy based at least in part on a determination that a central peak width of the signal is above a high central peak width threshold.

"In some embodiments, under control of the signal processor the system classifies the signal as weak based at least in part on a determination that no non-central peak width of the signal is above a non-central peak width threshold.

"These and other aspects of the invention will be better understood by reference to the following detailed description taken in conjunction with the drawings that are briefly described below. Of course, the invention is defined by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

"FIG. 1 shows an ambulatory monitoring system in some embodiments of the invention.

"FIG. 2 shows a good acoustic physiological signal received by a signal processor in some embodiments of the invention.

"FIG. 3 shows an envelope of the signal of FIG. 2.

"FIG. 4 shows an autocorrelation curve of the envelope of FIG. 3.

"FIG. 5 shows a noisy acoustic physiological signal received by a signal processor in some embodiments of the invention.

"FIG. 6 shows an envelope of the signal of FIG. 5.

"FIG. 7 shows an autocorrelation curve of the envelope of FIG. 6.

"FIG. 8 shows a weak acoustic physiological signal received by a signal processor in some embodiments of the invention.

"FIG. 9 shows an envelope of the signal of FIG. 8.

"FIG. 10 shows an autocorrelation curve of the envelope of FIG. 9.

"FIG. 11 shows an acoustic physiological signal processing method in some embodiments of the invention.

"FIG. 12 shows a peak having a measured width in some embodiments of the invention.

"FIG. 13 shows signal classification steps of an acoustic physiological signal processing method in some embodiments of the invention."

For additional information on this patent application, see: Fu, Yongji; Yang, Te-Chung Isaac. Physiological Signal Quality Classification for Ambulatory Monitoring. Filed September 20, 2013 and posted January 30, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=968&p=20&f=G&l=50&d=PG01&S1=20140123.PD.&OS=PD/20140123&RS=PD/20140123

Keywords for this news article include: Treatment, Electronics, Chronic Disease, Signal Processing, Sharp Laboratories of America Inc..

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Source: Electronics Newsweekly


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