US-12616404-B1 - Mismatch compensation for biosensor electrodes

Abstract

The disclosed computer-implemented method may include measuring one or more electrical properties from a plurality of electrodes for biosignal measurement, determining, based on the measured one or more electrical properties, an impedance mismatch between at least a first electrode and a second electrode of the plurality of electrodes, and reducing the impedance mismatch by modulating an impedance of the first electrode. Various other methods, systems, and computer-readable media are also disclosed.

Inventors

• Eric VanWyk
• Brendan Patrick FLYNN
• Pinghung WEI
• Filipp DEMENSCHONOK

Assignees

• META PLATFORMS TECHNOLOGIES, LLC

Dates

Publication Date

20260505

Application Date

20221018

Claims (20)

1. 1 . A method comprising: measuring one or more electrical properties from a plurality of electrodes for biosignal measurement; selecting a reference electrode from the plurality of electrodes based on the measured one or more electrical properties, wherein a second electrode corresponds to the reference electrode; determining, based on the measured one or more electrical properties, an impedance mismatch between at least a first electrode and the second electrode of the plurality of electrodes; and reducing the impedance mismatch by modulating an impedance of the first electrode.
2. 2 . The method of claim 1 , wherein: measuring the one or more electrical properties includes measuring a first impedance of the first electrode and a second impedance of the second electrode; determining the impedance mismatch includes comparing the first impedance to the second impedance; and reducing the impedance mismatch includes modulating the impedance of the first electrode based on the comparison.
3. 3 . The method of claim 1 , wherein: measuring the one or more electrical properties includes measuring a signal using the plurality of electrodes; determining the impedance mismatch includes predicting the impedance mismatch using the measured signal; and reducing the impedance mismatch includes modulating the impedance of the first electrode based on the predicted impedance mismatch.
4. 4 . The method of claim 1 , wherein reducing the impedance mismatch further comprises: determining an updated impedance mismatch in response to modulating the impedance of the first electrode; determining whether the updated impedance mismatch satisfies an error margin; and modulating the impedance of the first electrode in response to determining that the updated impedance mismatch does not satisfy the error margin.
5. 5 . The method of claim 1 , further comprising selecting a weak electrode from the plurality of electrodes and disregarding measurements from the weak electrode.
6. 6 . The method of claim 1 , wherein reducing the impedance mismatch further comprises modulating the impedance of the first electrode using an impedance modulating circuit.
7. 7 . The method of claim 6 , wherein the impedance modulating circuit comprises one or more variable impedance blocks.
8. 8 . The method of claim 6 , wherein the impedance modulating circuit comprises one or more switched capacitors.
9. 9 . The method of claim 6 , further comprising: measuring a signal using the plurality of electrodes; and downconverting the measured signal using the impedance modulating circuit.
10. 10 . A biosensing device comprising: a plurality of electrodes for biosignal measurement; an electrical property measurement circuit; an impedance modulating circuit; and at least one physical processor configured to: measure, using the electrical property measurement circuit, one or more electrical properties from the plurality of electrodes; select a reference electrode from the plurality of electrodes based on the measured one or more electrical properties, wherein a second electrode corresponds to the reference electrode; determine, based on the measured one or more electrical properties, an impedance mismatch between at least a first electrode and the second electrode of the plurality of electrodes; and reduce the impedance mismatch by modulating an impedance of the first electrode using the impedance modulating circuit.
11. 11 . The biosensing device of claim 10 , wherein: measuring the one or more electrical properties includes measuring a first impedance of the first electrode and a second impedance of the second electrode; determining the impedance mismatch includes comparing the first impedance to the second impedance; and reducing the impedance mismatch includes modulating the impedance of the first electrode based on the comparison.
12. 12 . The biosensing device of claim 10 , wherein: measuring the one or more electrical properties includes measuring a signal using the plurality of electrodes; determining the impedance mismatch includes predicting the impedance mismatch using the measured signal; and reducing the impedance mismatch includes modulating the impedance of the first electrode based on the predicted impedance mismatch.
13. 13 . The biosensing device of claim 10 , wherein reducing the impedance mismatch further comprises: determining an updated impedance mismatch in response to modulating the impedance of the first electrode; determining whether the updated impedance mismatch satisfies an error margin; and modulating the impedance of the first electrode in response to determining that the updated impedance mismatch does not satisfy the error margin.
14. 14 . The biosensing device of claim 10 , further comprising selecting a weak electrode from the plurality of electrodes and disregarding measurements from the weak electrode.
15. 15 . The biosensing device of claim 10 , wherein the impedance modulating circuit comprises one or more variable impedance blocks.
16. 16 . The biosensing device of claim 10 , wherein the impedance modulating circuit comprises one or more switched capacitors.
17. 17 . The biosensing device of claim 10 , further comprising: measuring a signal using the plurality of electrodes; and downconverting the measured signal using the impedance modulating circuit.
18. 18 . A system comprising: at least one physical processor; physical memory comprising computer-executable instructions; and a biosensing device comprising: a plurality of electrodes for biosignal measurement; an electrical property measurement circuit; and an impedance modulating circuit; wherein the at least one physical processor is configured to: measure, using the electrical property measurement circuit, one or more electrical properties from the plurality of electrodes; select a reference electrode from the plurality of electrodes based on the measured one or more electrical properties, wherein a second electrode corresponds to the reference electrode; determine, based on the measured one or more electrical properties, an impedance mismatch between at least a first electrode and the second electrode of the plurality of electrodes; and reduce the impedance mismatch by modulating an impedance of the first electrode using the impedance modulating circuit.
19. 19 . The system of claim 18 , wherein: measuring the one or more electrical properties includes measuring a first impedance of the first electrode and a second impedance of the second electrode; determining the impedance mismatch includes comparing the first impedance to the second impedance; and reducing the impedance mismatch includes modulating the impedance of the first electrode based on the comparison.
20. 20 . The system of claim 18 , wherein: measuring the one or more electrical properties includes measuring a signal using the plurality of electrodes; determining the impedance mismatch includes predicting the impedance mismatch using the measured signal; and reducing the impedance mismatch includes modulating the impedance of the first electrode based on the predicted impedance mismatch.

Description

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings illustrate a number of exemplary embodiments and are a part of the specification. Together with the following description, these drawings demonstrate and explain various principles of the present disclosure. FIG. 1 is a diagram of an exemplary biosensor electrode environment. FIGS. 2A-C are diagrams of example variable impedance circuits for biosensor devices. FIGS. 3A-C are diagrams of example variable impedance circuits for biosensor devices. FIG. 4 is a flow diagram of an exemplary method for compensating for mismatches in biosensor electrodes. FIG. 5 is a graph of an example noise spectrum. FIG. 6 is an illustration of exemplary augmented-reality glasses that may be used in connection with embodiments of this disclosure. FIG. 7 is an illustration of an exemplary virtual-reality headset that may be used in connection with embodiments of this disclosure. FIGS. 8A and 8B are illustrations of an exemplary human-machine interface configured to be worn around a user's lower arm or wrist. FIGS. 9A and 9B are illustrations of an exemplary schematic diagram with internal components of a wearable system. Throughout the drawings, identical reference characters and descriptions indicate similar, but not necessarily identical, elements. While the exemplary embodiments described herein are susceptible to various modifications and alternative forms, specific embodiments have been shown byway of example in the drawings and will be described in detail herein. However, the exemplary embodiments described herein are not intended to be limited to the particular forms disclosed. Rather, the present disclosure covers all modifications, equivalents, and alternatives falling within the scope of the appended claims. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS Electromyography (EMG) devices and other biosensing or biosignal measurement devices (e.g., electrocardiograms (ECG), electroencephalograms (EEG), etc.) may measure electrical activity of a human body. Biosensing devices may measure EMG and other electrical signals emitted by the human body to measure certain aspects of the body, such as in a medical diagnostic context. These electrical signals may also be used as inputs for input devices of computing devices. These electrical signals are often small, for example in an order of magnitude of micro-volts. Due to the precision necessary for accurate measurements, any noise may greatly influence accuracy. Biosensing measurements may further be influenced by the electrical properties of the biosensing devices themselves. For example, the electrodes of the biosensing devices may exhibit different electrical properties such that the inputs from the electrodes may be unbalanced. The unbalanced inputs may introduce noise. In some cases, the high variability of the skin-electrode interface may cause the unbalance. Thus, electrically balancing the electrodes for biosensing may reduce noise and improve measurement accuracy. The present disclosure is generally directed to mismatch compensation for biosensor electrodes. As will be explained in greater detail below, embodiments of the present disclosure may measure electrical properties from electrodes for biosignal measurement, determine an impedance mismatch between two of the electrodes, and reduce the impedance mismatch by modulating an impedance of at least one of the two electrodes. By modulating the impedances of electrodes, impedance mismatches can be better balanced to reduce noise in biosignal measurement. Features from any of the embodiments described herein may be used in combination with one another in accordance with the general principles described herein. These and other embodiments, features, and advantages will be more fully understood upon reading the following detailed description in conjunction with the accompanying drawings and claims. The following will provide, with reference to FIGS. 1-5, detailed descriptions of systems and methods for compensating for mismatches in electrical properties between biosensor electrodes. Detailed descriptions of an example skin-electrode interface are provided in connection with FIG. 1. Detailed descriptions of example impedance modulating circuits are provided in connection with FIGS. 2A-C and 3A-C. Detailed descriptions of an example method for mismatch compensation for biosensor electrodes are provided in connection with FIG. 4. Detailed descriptions of a noise spectrum are provided in connection with FIG. 5. FIG. 1 illustrates a biosensing device 100 and an example skin-electrode interface with a skin 112 of a user. As illustrated in FIG. 1, biosensing device 100 may include one or more electrodes 110 (e.g., an electrode 110A, an electrode 110B, an electrode 110C, and an electrode 110D), an analog front end 150 which may include an electrical property measurement circuit 140 and an impedance modulating circuit 120, and a processor 130. Electrodes 110A-D may correspond