KR20230127840A - Apparatus and method for measuring biosignals using array-based sensor - Google Patents

Abstract

An apparatus and method for measuring a biosignal using an array-based sensor are disclosed. An apparatus for measuring a biosignal using an array-based sensor according to an embodiment of the present disclosure includes a sensing unit including optical active elements or mechanical passive sensing elements configured in an array form; and a control unit controlling the sensing unit to analyze signals output from each of the optical active elements or the mechanical passive sensing elements to measure a biosignal of the target.

Description

Apparatus and method for measuring bio-signals using an array-based sensor {APPARATUS AND METHOD FOR MEASURING BIOSIGNALS USING ARRAY-BASED SENSOR}

The present disclosure relates to a method and apparatus for measuring a biosignal, and more particularly, to an apparatus and method for measuring a biosignal using an array-based sensor.

A biosignal is a signal that detects a change in a living body, and a method for detecting a change can be largely classified into electrical, optical, and mechanical methods.

An electrical method measures a potential difference generated in a living body and is called an electrophysiological signal, and representatively, electrocardiography and electroencephalography correspond thereto.

Optical methods detect changes in absorbance of blood flow, and include photoplethysmography, pulse oximetry, functional near-infrared spectroscopy, and the like.

The mechanical method measures mechanical movement generated by heartbeat, and includes ballistocardiography, blood pressure, and the like.

An object of the present disclosure is to provide a device and method for measuring a biosignal using an array-based sensor.

The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description below. You will be able to.

According to embodiments of the present disclosure, an apparatus and method for measuring a biosignal using an array-based sensor are disclosed. An apparatus for measuring a biosignal using an array-based sensor according to an embodiment of the present disclosure includes a sensing unit including optical active elements or mechanical passive sensing elements configured in an array form; and a control unit controlling the sensing unit to analyze signals output from each of the optical active elements or the mechanical passive sensing elements to measure a biosignal of the target.

At this time, the sensing unit includes a light source unit including light source elements in an array form and emitting light from each of the light source elements to the target; and a light receiving unit configured to receive light passing through the target from each of the light receiving elements, wherein the control unit analyzes a signal output from each of the light receiving elements and analyzes the biosignal of the target. can measure

At this time, the control unit measures the signal-to-noise ratio of each pixel by analyzing signals output from each of the optical active elements or the mechanical passive sensing elements, assigns a weight to each pixel according to the signal-to-noise ratio, The biological signal of the target may be separated from the noise reference signal using the assigned weight, and the noise of the biosignal may be removed using the noise reference signal.

In this case, the control unit may control a light source pattern emitted from the light source unit based on the signal-to-noise ratio of each pixel.

At this time, the control unit may control a light source pattern emitted from the light source unit.

At this time, the control unit may control the light source pattern by adjusting the on/off of each of the light source elements and the intensity of light.

A biological signal measuring method using an array-based sensor according to another embodiment of the present disclosure includes measuring signals from sensing elements including optical active elements or mechanical passive sensing elements configured in an array form; and extracting a biological signal of a target by analyzing signals measured from each of the optical active elements or the mechanical passive sensing elements.

In this case, the step of extracting the biological signal of the target may include controlling each of the sensing elements based on the measured signal; separating a biosignal of the target from a noise reference signal by combining measured signals of each of the sensing elements; and extracting the noise-removed biosignal of the target by removing noise of the biosignal using the noise reference signal.

The features briefly summarized above with respect to the disclosure are merely exemplary aspects of the detailed description of the disclosure that follows, and do not limit the scope of the disclosure.

According to the present disclosure, an apparatus and method for measuring a biosignal using an array-based sensor may be provided.

Effects obtainable in the present disclosure are not limited to the effects mentioned above, and other effects not mentioned may be clearly understood by those skilled in the art from the description below. will be.

1 is an exemplary view for explaining a method of measuring a photoplethysmogram.
2 illustrates a configuration of a bio-signal measuring device according to an embodiment of the present disclosure.
3 illustrates a configuration of a bio-signal measuring device according to another embodiment of the present disclosure.
4 shows an example of an arrangement structure for a light source unit and a light receiver.
5 is a flowchart illustrating an operation of a bio-signal measurement method according to another embodiment of the present disclosure.
6 is a flowchart illustrating an operation of a biosignal measurement method according to another embodiment of the present disclosure.
7 is a block diagram of a device to which an apparatus for measuring biosignals according to another embodiment of the present disclosure is applied.

Hereinafter, with reference to the accompanying drawings, embodiments of the present disclosure will be described in detail so that those skilled in the art can easily implement the present disclosure. However, this disclosure may be embodied in many different forms and is not limited to the embodiments set forth herein.

In describing the embodiments of the present disclosure, if it is determined that a detailed description of a known configuration or function may obscure the gist of the present disclosure, a detailed description thereof will be omitted. And, in the drawings, parts irrelevant to the description of the present disclosure are omitted, and similar reference numerals are attached to similar parts.

In the present disclosure, when a component is said to be "connected", "coupled" or "connected" to another component, this is not only a direct connection relationship, but also an indirect connection relationship where another component exists in the middle. may also be included. In addition, when a component "includes" or "has" another component, this means that it may further include another component without excluding other components unless otherwise stated. .

In the present disclosure, terms such as first and second are used only for the purpose of distinguishing one element from another, and do not limit the order or importance of elements unless otherwise specified. Accordingly, within the scope of the present disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment. can also be called

In the present disclosure, elements that are distinguished from each other are only for clearly describing each characteristic, and do not necessarily mean that the elements are separated. That is, a plurality of components may be integrated to form a single hardware or software unit, or a single component may be distributed to form a plurality of hardware or software units. Accordingly, even such integrated or distributed embodiments are included in the scope of the present disclosure, even if not mentioned separately.

In the present disclosure, components described in various embodiments do not necessarily mean essential components, and some may be optional components. Accordingly, an embodiment comprising a subset of elements described in one embodiment is also included in the scope of the present disclosure. In addition, embodiments including other components in addition to the components described in various embodiments are also included in the scope of the present disclosure.

In the present disclosure, expressions of positional relationships used in this specification, such as upper, lower, left, right, etc., are described for convenience of description, and when viewing the drawings shown in this specification in reverse, the positions described in the specification Relationships can also be interpreted in reverse.

In the present disclosure, "A or B", "at least one of A and B", "at least one of A or B", "A, B or C", "at least one of A, B and C", and " Each of the phrases such as “at least one of A, B, or C” may include any one of the items listed together in that phrase, or all possible combinations thereof.

A biosignal is a signal that detects a change in a living body, and a method for detecting a change can be largely classified into electrical, optical, and mechanical methods.

The optical and mechanical methods, which can be measured at one point where the sensor is attached, have a simpler sensor configuration than the electrical method, which requires a lot of electrodes.

Blood pressure, which is a mechanical signal, measures the pressure in blood vessels, and ballistics measures changes in vibration of the body according to heartbeat. There are various types of sensors that measure each signal, but the measurement principle consists of measuring the pressure between the body and the sensor. Accordingly, in order to obtain a desired signal, a sensor may be attached to a location where a target body movement occurs, for example, a location where oriental doctors take a pulse and measure the signal. On the other hand, if the desired body movement is not captured at the location where the sensor is attached, there is a problem in that only noise is measured, not a signal. After all, in order to obtain a signal with a high signal-to-noise ratio (SNR), the sensor must be placed in an accurate position. Another issue to consider with the sensor location issue is that the signal is very easily corrupted by motion artifacts caused by body movements. It is noteworthy that the mechanical signal measurement method and the dynamic noise interference method are similar.

Photoplethysmography, pulse oximetry, and functional near-infrared spectroscopy, all of which are optical signals, measure signals that are absorbed by body tissues, such as skin, bones, and blood vessels, and reflected from light emitted from a light source. At this time, through the signal, it is possible to measure the change in blood volume and the level of oxygen saturation. It is noteworthy that the signals to be observed are ultimately determined by the absorbance of blood vessels, that is, the amount of light absorbed. For example, as shown in FIG. 1 for measuring a photoplethysmogram, light passes through a blood vessel and reaches a photo detector (PD) while drawing a banana curve, whereby a signal is detected. At this time, in order to measure the absorbance of the target blood vessel, the location of the light source (LED) and the PD (eg, the location of the blood vessel), the distance between the light source and the PD (eg, the depth from the skin to the blood vessel) ), the intensity of the light source (for example, the width of a banana curve), etc. The signal-to-noise ratio is determined according to the sensor setting, and this is the reason why recently released smart watch heart rate sensors are complicated in arrangement. Along with the sensor positioning issue, the optical signal is also very easily polluted by noise. Optical sensors are very vulnerable to interference from external light as well as motion noise caused by movement. Finally, the optical sensor needs to adjust the intensity of the light source as weakly as possible for photobiological safety. In order to stably measure the signal of the target blood vessel and minimize the intensity of the light source, the location of the light source and the PD must be optimized according to the blood vessel.

Various noise removal techniques have been proposed to solve the noise problem of biosignals. The most representative technology is ANC technology, also called adaptive noise canceling or active noise canceling. One of the hottest markets recently is ANC, which is noise canceling used in the noise canceling earphone market. ANC is a technology that measures a separate noise reference signal and removes actual noise based on the reference signal. ANC performance depends on obtaining a noise reference signal similar to real noise. In order for the noise reference signal to be similar to actual noise, the signal and the noise reference signal need to have the same measurement modality. For example, noise canceling earphones can improve noise canceling performance because both the music signal and the noise reference signal are measured with a microphone. A large reason for the performance limitations of existing ANCs for removing bio-signal noise is that the modalities of the noise reference signals are different.

Recently, in an optical sensor analog front end (AFE) chip for measuring biosignals, a plurality of LED and PD drivers are provided to configure an array type sensor. As a conventional technology of an embodiment, in order to optimize bio-signal measurement, array-type PDs were used and optimal PD pixels were selected and used. However, the technology does not drive LEDs in an array-type, and PDs other than the selected PD pixels do not use them That is, since the technology is limited in finding the optimal sensing position due to the fixed LED position, it may cause problems with a low signal-to-noise ratio and photobiological safety, and by not using a PD other than the selected PD, resources are conserved. wasteful, and does not provide an adequate solution to noise cancellation.

The gist of the embodiments of the present disclosure is to solve the measurement position selection problem and the noise removal problem of the optical or mechanical biosignal sensors based on the sensor structure of the array type.

2 shows the configuration of a bio-signal measuring device according to an embodiment of the present disclosure, and shows the configuration of a mechanical bio-signal measuring device.

Referring to FIG. 2 , a biosignal measuring device 200 according to an embodiment of the present disclosure includes a piezoelectric element unit 210 and a controller 220 .

The piezoelectric element unit 210 includes an array of piezoelectric elements, and each of the piezoelectric cells constituting the piezoelectric element receives pressure from a blood vessel in the body in the target case.

The control unit 220 analyzes signals received from each of the piezoelectric cells in the array type piezoelectric element, measures the signal-to-noise ratio of each pixel, that is, each piezoelectric cell, and assigns a weight to each pixel according to the signal-to-noise ratio. After that, the biological signal and the noise reference signal are separated using the assigned weight, and noise is removed from the biological signal using the noise reference signal, thereby measuring the biological signal from which the noise has been removed.

Here, the controller 220 may measure the signal-to-noise ratio of each piezoelectric cell by utilizing the amplitude of the heartbeat signal.

The controller 220 may assign a weight of 0 to 1 to each pixel according to the signal-to-noise ratio. For example, a weight of 1 is assigned to a signal, a weight of 0 is assigned to noise, and a weight matrix of all pixels. (weight matrix) W can be generated.

In this case, the biosignal d(n) and the noise reference signal x(n) can be expressed by Equation 1 and Equation 2 below.

[Equation 1]

d(n)=∑(S(n)○W)

[Equation 2]

x(n)=∑(S(n)○(1-W))

Here, ○ may mean a Hadamard product.

The biological signal e(n) from which noise is removed through Equation 1 and Equation 2 can be measured by d(n)-f(x(n)). Here, f() may mean a linear or non-linear function.

3 shows the configuration of a biosignal measuring device according to another embodiment of the present disclosure, and shows the configuration of an optical biosignal measuring device.

Referring to FIG. 3 , a biosignal measuring device 300 according to another embodiment of the present disclosure includes a light source unit 310 , a light receiving unit 320 and a control unit 330 .

The light source unit 310 includes an array of light source elements, and emits light from each of the light source elements to a target, in this case, a blood vessel in the body.

The light receiving unit 320 includes array-shaped light-receiving elements, and each of the array-shaped light-receiving elements receives light received through the body.

Depending on the embodiment, the light source unit (or light emitting unit) 310 and the light receiving unit 320 may have an arrangement as shown in FIG. 4 . For example, disposing the first light source element at the center of the circle, disposing a plurality of light receiving elements so as to surround the first light source element, disposing the plurality of light receiving elements again so as to surround the light receiving elements, and placing the light source elements By rearranging a plurality of light-receiving elements so as to surround the light source unit and the light-receiving unit of the form shown in FIG.

The control unit 330 controls the light source pattern for the light source elements of the array form of the light source unit 310, and analyzes the output signal corresponding to the light received by each light receiving element from the array form light receiver 320 to each pixel. After measuring the signal-to-noise ratio of , and assigning a weight to each pixel according to the signal-to-noise ratio, using the assigned weight, separates the biosignal and noise reference signal of the target, and utilizes the noise reference signal By removing the noise of the biosignal, the biosignal from which the noise has been removed is measured.

At this time, the controller 330 can control the pattern of the light source by controlling each light source element, that is, the on/off of each light source element and the intensity of light in detail. .

In this case, the controller 330 may control the light source pattern emitted from the light source unit 310 based on the signal-to-noise ratio of each pixel.

In this case, the controller 330 may measure the signal-to-noise ratio of each pixel by utilizing the amplitude of the heartbeat signal.

The controller 330 may assign a weight of 0 to 1 to each pixel according to the signal-to-noise ratio. For example, a weight of 1 is assigned to a signal, a weight of 0 is assigned to noise, and a weight matrix of all pixels. (weight matrix) W can be generated. In addition, the biosignal and the noise reference signal can be calculated by <Equation 1> and <Equation 2>, and the biosignal from which noise has been removed can be measured using the biosignal and the noise reference signal.

As described above, the biosignal measuring device according to the embodiments of the present disclosure has an array-type sensor structure, and thus can solve the measurement position selection problem and the noise removal problem of optical or mechanical biosignal sensors.

The location and distribution of blood vessels cannot be grasped outside the skin, and the location and distribution of these blood vessels vary depending on the wearing position and individual differences. As described above, for optimal signal measurement, it is advantageous to have a wide control range (position/distance/intensity) between the light source and the light receiver PD, and the control of the light source is easier and less costly than the control of the light receiver, which requires A/D conversion. cheaper For this reason, the 1:N configuration of the light receiver:light source unit is more efficient than the N:1 configuration. The size of the light receiver and the array of light sources can be configured in various ways, and a light source pattern optimized for blood vessel distribution can obtain a high-quality signal with a small amount of light.

In addition, the bio-signal measuring device according to the embodiments of the present disclosure is more efficient than a method of controlling an array-type light receiver by controlling an array-type light source, and a light source pattern optimized for blood vessel distribution produces high quality with a small amount of light. Since signals can be obtained, not only energy efficiency but also photobiological safety can be improved.

FIG. 5 is an operational flow chart of a biosignal measuring method according to another embodiment of the present disclosure, and is an operational flowchart of the mechanical biosignal measuring method of FIG. 2 .

Referring to FIG. 5 , a method for measuring biosignals using a mechanical method according to an embodiment of the present disclosure analyzes a signal received by each of the cells constituting an array type sensor, and measures the signal of each pixel, for example, each piezoelectric cell. The noise ratio is measured, and a weight is assigned to each pixel according to the signal-to-noise ratio (S510 and S520).

Here, in step S510, the signal-to-noise ratio of each pixel may be measured using the amplitude of the signal, and in step S520, weights of 0 to 1 may be assigned to each pixel according to the signal-to-noise ratio.

When a weight is assigned to each pixel in step S520, a bio signal and a noise reference signal are separated using the assigned weight, and noise is removed from the bio signal using the noise reference signal, thereby obtaining a bio signal from which the noise has been removed. Measure (S530, S540).

FIG. 6 is an operation flow chart of a bio-signal measurement method according to another embodiment of the present disclosure, which is an operation flow chart of a bio-signal measurement method using an optical method.

Referring to FIG. 8 , in an optical biosignal measuring method according to an embodiment of the present disclosure, a light source pattern for arrayed light source elements is controlled, and received by each of the arrayed light receiving elements according to the light source pattern. The signal is analyzed to measure the signal-to-noise ratio of each pixel, for example, each receiving element (S610 and S620).

Here, in step S610, each of the light source elements may be turned on/off according to a preset light source pattern, and in step S620, the signal-to-noise ratio of each pixel may be measured using the amplitude of the signal.

Then, the steps S610 and S620 are repeatedly controlled to form the optimal light source pattern, and when the optimal light source pattern is irradiated to the target, a weight is assigned to each pixel according to the signal-to-noise ratio of each pixel with respect to the optimal light source pattern. (S630, S640).

Here, in step S630 , a light source pattern in which the intensity of the light source versus the pulse of the measurement signal, for example, the AC component is maximized, may be determined as the optimal light source pattern.

At this time, in step S630, a weight of 0 to 1 may be assigned to each pixel according to the signal-to-noise ratio.

When a weight is assigned to each pixel in step S640, the bio signal and the noise reference signal are separated using the assigned weight, and noise is removed from the bio signal using the noise reference signal, thereby obtaining the bio signal from which the noise has been removed. Measure (S650, S660).

Even if the description is omitted in the method of FIGS. 5 and 6, the method according to the embodiment of the present disclosure may include all the contents described in the device of FIGS. 2 to 4, which is skilled in the art self-evident for

7 is a block diagram of a device to which an apparatus for measuring biosignals according to another embodiment of the present disclosure is applied.

For example, the device 1600 of FIG. 7 may be the device 1600 of FIG. 3 for measuring a biosignal according to another embodiment of the present disclosure. Referring to FIG. 7 , a device 1600 may include a memory 1602 , a processor 1603 , a transceiver 1604 and a peripheral device 1601 . Also, as an example, the device 1600 may further include other configurations, and is not limited to the above-described embodiment. In this case, the device 1600 may be, for example, a fixed network management device (eg, a server, a PC, etc.).

More specifically, the device 1600 of FIG. 7 may be an exemplary hardware/software architecture such as a non-invasive bio-signal measuring device, a wearable device, a blood pressure measuring device, and the like. At this time, for example, the memory 1602 may be a non-removable memory or a removable memory. Also, as an example, the peripheral device 1601 may include a display, GPS, or other peripheral devices, and is not limited to the above-described embodiment.

Also, as an example, the above-described device 1600 may include a communication circuit like the transceiver 1604, and based on this, communication with an external device may be performed.

Also, as an example, the processor 1603 may include a general purpose processor, a digital signal processor (DSP), a DSP core, a controller, a microcontroller, application specific integrated circuits (ASICs), field programmable gate array (FPGA) circuits, any other It may be at least one or more of a tangible integrated circuit (IC) and one or more microprocessors associated with a state machine. That is, it may be a hardware/software configuration that performs a control role for controlling the device 1600 described above. In addition, the processor 1603 can modularize and perform the functions of the control unit 330 of FIG. 3 described above.

In this case, the processor 1603 may execute computer executable instructions stored in the memory 1602 to perform various essential functions of the bio-signal measuring device. For example, the processor 1603 may control at least one of signal coding, data processing, power control, input/output processing, and communication operations. Also, the processor 1603 may control a physical layer, a MAC layer, and an application layer. Also, as an example, the processor 1603 may perform authentication and security procedures in an access layer and/or an application layer, and is not limited to the above-described embodiment.

For example, the processor 1603 may communicate with other devices through the transceiver 1604 . For example, the processor 1603 may control the biosignal measurement device to communicate with other devices through a network through execution of computer executable instructions. That is, the communication performed in the present disclosure can be controlled. For example, the transceiver 1604 may transmit an RF signal through an antenna and may transmit the signal based on various communication networks.

In addition, as an example, MIMO technology, beamforming, etc. may be applied as an antenna technology, and is not limited to the above-described embodiment. In addition, the signal transmitted and received through the transceiver 1604 may be modulated and demodulated and controlled by the processor 1603, and is not limited to the above-described embodiment.

Exemplary methods of this disclosure are presented as a series of operations for clarity of explanation, but this is not intended to limit the order in which steps are performed, and each step may be performed concurrently or in a different order, if desired. In order to implement the method according to the present disclosure, other steps may be included in addition to the exemplified steps, other steps may be included except for some steps, or additional other steps may be included except for some steps.

Various embodiments of the present disclosure are intended to explain representative aspects of the present disclosure, rather than listing all possible combinations, and matters described in various embodiments may be applied independently or in combination of two or more.

In addition, various embodiments of the present disclosure may be implemented by hardware, firmware, software, or a combination thereof. For hardware implementation, one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), It may be implemented by a processor (general processor), controller, microcontroller, microprocessor, or the like.

The scope of the present disclosure is software or machine-executable instructions (eg, operating systems, applications, firmware, programs, etc.) that cause operations according to methods of various embodiments to be executed on a device or computer, and such software or It includes a non-transitory computer-readable medium in which instructions and the like are stored and executable on a device or computer.

300 vital signal measuring device
310 light source
320 light receiver
330 Control

Claims (1)

a sensing unit including optical active elements or mechanical passive sensing elements configured in an array form; and
A control unit that controls the sensing unit to analyze signals output from each of the optical active elements or the mechanical passive sensing elements to measure the biosignal of the target.
Including, bio-signal measuring device.

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