WO2013084719A1

WO2013084719A1 - Measurement device, measurement method, program and recording medium

Info

Publication number: WO2013084719A1
Application number: PCT/JP2012/080200
Authority: WO
Inventors: 中村　憲一郎; 佐藤　英雄
Original assignee: ソニー株式会社
Priority date: 2011-12-08
Filing date: 2012-11-21
Publication date: 2013-06-13
Also published as: JP2013118978A; JP5948831B2

Abstract

[Problem] To provide a measurement device, measurement method, program and recording medium capable of separating the arterial pulse component without using frequency filters with sharp cutoff characteristics. [Solution] The measurement device of this disclosure is provided with: a measuring unit that irradiates light of a prescribed wavelength on at least a portion of a living body, images said living body with an image sensor, and measures the degree of light absorption by the living body; a vein position-specifying unit that specifies the position of a vein present in the interior of the living body at the measurement site of the living body using the measurement data; a pulse component-separating unit that, on the basis of temporal changes of the measurement data and the position of the vein, separates the component, which is derived from the pulsing of an artery present in the interior of the living body, from among the temporal changes of the measurement data; and an oxygen saturation-calculating unit that calculates the oxygen saturation in the arterial blood using the component derived from the arterial pulse in the separated measurement data.

Description

Measuring device, measuring method, program, and recording medium

The present disclosure relates to a measuring device, a measuring method, a program, and a recording medium.

In the medical field, a technique for measuring a pulse waveform (arterial pulse waveform) is frequently used. The pulse waveform is used for circulatory system examination (for example, arteriosclerosis measurement, stress measurement) by analyzing the waveform shape, and also for pulse oximeter (arterial blood oxygen saturation measuring device) etc. It's being used.

Among them, a technique called optical volume pulse wave method (see, for example, Patent Document 1 below), which is one of techniques for measuring a pulse waveform transcutaneously without blood collection or puncture. ) Is used in a very wide range because it can be easily measured without imposing a burden on the human body.

JP 2003-135434 A

In the measurement of the pulse waveform using the optical volume pulse wave method as described above, the time of light absorption by arterial blood using a frequency filter from a state where light absorption by arterial blood, venous blood, and other body components is mixed. Techniques that isolate only fluctuations play an important role.

By the way, a human pulse is usually about 50 to 150 times per minute, which corresponds to a signal of about 0.8 Hz to 2.5 Hz in the frequency domain. In order to clearly separate such a signal in a relatively low frequency band from the DC component (0 Hz), a frequency filter having a steep cut-off characteristic is used.

In general, filter circuits having steep cut-off characteristics tend to be large in scale, and it has been difficult to ensure sufficient performance with a filter circuit of a practical scale. For this reason, there may occur a case where the pulsation component cannot be sufficiently separated under adverse conditions such as a case where sufficient pulsation cannot be obtained due to low perfusion.

Therefore, in view of the above circumstances, the present disclosure proposes a measuring device, a measuring method, a program, and a recording medium that can separate arterial pulsation components without using a frequency filter having a steep cutoff characteristic. To do.

According to the present disclosure, a measuring unit that irradiates at least a part of a living body with light having a predetermined wavelength, images the living body with an image sensor, and measures the degree of absorption of the light by the living body, and the measuring unit Using the measurement data obtained by the above, the vein position specifying unit for specifying the position corresponding to the vein existing inside the living body at the measurement site of the living body, the time change of the measurement data by the measuring unit, and the vein position specifying A pulsation component separation unit that separates components derived from pulsations of arteries existing in the living body from time changes of the measurement data based on the position of the vein specified by the unit; An oxygen saturation calculation unit that calculates oxygen saturation in arterial blood using a component derived from the pulsation of the artery of the measurement data separated by the dynamic component separation unit is provided. It is.

According to the present disclosure, at least a part of a living body is irradiated with light of a predetermined wavelength, the living body is imaged by an image sensor, and the degree of absorption of the light by the living body is measured. Using the measured data, the position corresponding to the vein existing inside the living body at the measurement site of the living body, the time change of the measurement data, and the position of the specified vein Based on this, the component derived from the pulsation of the artery existing inside the living body among the time changes of the measurement data is separated, and the component derived from the pulsation of the artery of the separated measurement data is used And calculating oxygen saturation in arterial blood.

According to the present disclosure, it is possible to communicate with a measurement unit that irradiates at least a part of a living body with light of a predetermined wavelength, images the living body with an image sensor, and measures the degree of absorption of the light by the living body. And a vein position specifying function for specifying a position corresponding to a vein existing in the living body at a measurement site of the living body using measurement data by the measuring section, and a time of measurement data by the measuring section Based on the change and the position of the vein specified by the vein position specifying function, the pulsation that separates components derived from the pulsation of the artery existing inside the living body from the temporal change of the measurement data Oxygen for calculating oxygen saturation in arterial blood using a component separation function and a component derived from the pulsation of the artery of the measurement data separated by the pulsation component separation function Program for realizing a sum calculation function is provided.

According to the present disclosure, it is possible to communicate with a measurement unit that irradiates at least a part of a living body with light of a predetermined wavelength, images the living body with an image sensor, and measures the degree of absorption of the light by the living body. And a vein position specifying function for specifying a position corresponding to a vein existing in the living body at a measurement site of the living body using measurement data by the measuring section, and a time of measurement data by the measuring section Based on the change and the position of the vein specified by the vein position specifying function, the pulsation that separates components derived from the pulsation of the artery existing inside the living body from the temporal change of the measurement data Oxygen for calculating oxygen saturation in arterial blood using a component separation function and a component derived from the pulsation of the artery of the measurement data separated by the pulsation component separation function Recording medium having a program recorded thereon for realizing a sum calculation function is provided.

According to the present disclosure, the measurement unit that irradiates at least a part of a living body with light having a predetermined wavelength, images the living body with an image sensor, and measures the degree of absorption of the light by the living body; Utilizing measurement data by the measurement unit, a vein position specifying unit that specifies a position corresponding to a vein existing inside the living body at the measurement site of the living body, a time change of the measurement data by the measuring unit, and the vein Based on the position of the vein specified by the position specifying unit, a pulsation component separation unit that separates a component derived from the pulsation of an artery existing inside the living body from the time change of the measurement data, An oxygen saturation calculation unit that calculates oxygen saturation in arterial blood using a component derived from the pulsation of the artery of the measurement data separated by the pulsation component separation unit, and the measurement The light source unit that emits at least two types of measurement light of red light and infrared light having a predetermined wavelength toward the living body, and a plurality of sensors are regularly arranged in a predetermined arrangement, There is provided a measurement device having a detection unit that detects, with the plurality of sensors, measurement light emitted from a light source unit and transmitted through the living body.

According to the present disclosure, at least a part of a living body is irradiated with light of a predetermined wavelength, the living body is imaged by an image sensor, and the degree of absorption of the light by the living body is measured. Using the measured data, the position corresponding to the vein existing inside the living body at the measurement site of the living body, the time change of the measurement data, and the position of the specified vein Based on this, the component derived from the pulsation of the artery existing inside the living body among the time changes of the measurement data is separated, and the component derived from the pulsation of the artery of the separated measurement data is used And calculating oxygen saturation in arterial blood, and when measuring the degree of light absorption, at least two types of measurement light, red light and infrared light having a predetermined wavelength, To living body Selfish injection, multiple sensors by regularly disposed a sensor in a predetermined arrangement, for detecting the measurement light transmitted through the living body, measurement method is provided.

According to the present disclosure, at least a part of a living body is irradiated with light of a predetermined wavelength, and the living body is imaged by an image sensor, whereby the degree of absorption of the light by the living body is measured and measured. Using the data, a position corresponding to a vein existing inside the living body is specified in the measurement site of the living body, and based on the time change of the measurement data and the specified position of the vein, The component derived from the pulsation of the arteries existing inside the living body is separated from the time change of the measurement data, and the component derived from the pulsation of the arteries of the separated measurement data is used to Oxygen saturation is calculated.

As described above, according to the present disclosure, arterial pulsation components can be separated without using a frequency filter having a steep cutoff characteristic.

It is explanatory drawing shown about the structure of the general pulse oximeter. It is explanatory drawing shown about the structure of the general pulse oximeter. It is explanatory drawing which showed the relationship between the skin tissue of a biological body, and a light absorbency. It is a block diagram showing composition of a measuring device concerning a 1st embodiment of this indication. It is explanatory drawing for demonstrating the measurement part which concerns on the same embodiment. It is explanatory drawing for demonstrating the measurement part which concerns on the same embodiment. It is the block diagram shown about the vein position specific | specification part which concerns on the embodiment. It is the block diagram shown about the structure of the pulsation component separation part which concerns on the same embodiment. It is explanatory drawing which showed the relationship between the skin tissue of a biological body and the light absorbency in the measuring apparatus which concerns on the embodiment. It is the flowchart which showed an example of the whole flow of the measuring method concerning the embodiment. It is the flowchart which showed an example of the flow of the production | generation process of the vein mask which concerns on the embodiment. It is the flowchart which showed an example of the flow of the application process of the vein mask which concerns on the embodiment. It is a block diagram showing hardware constitutions of a measuring device concerning an embodiment of this indication.

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

The description will be made in the following order.
(1) Principle of pulse oximeter (2) First embodiment (2-1) Configuration of measurement device (2-2) Flow of measurement method (3) Measurement device according to an embodiment of the present disclosure Hardware configuration (4) Summary

(Pulse oximeter principle)
Prior to describing the measurement apparatus, measurement method, program, and recording medium according to the embodiments of the present disclosure, the principle of a general pulse oximeter using the optical volume pulse wave method will be described with reference to FIGS. However, I will explain briefly. 1 and 2 are explanatory diagrams showing the configuration of a general pulse oximeter. FIG. 3 is an explanatory diagram showing the relationship between the skin tissue of the living body and the absorbance.

A pulse oximeter is a device that measures the oxygen saturation of arterial blood percutaneously (referred to as percutaneous oxygen saturation, SpO2). As shown in FIG. 1, the pulse oximeter 700 includes a general pulse wave measuring device 701 as its component.

The pulse oximeter 700 measures biological information with an absorbance measurement unit 715 to which a measurement probe 703 is connected. As shown in FIG. 1, the measurement probe 703 includes a light emitting unit 711 and a light receiving unit 713, and measures a temporal change in light absorption by the living body, as will be described later. The measurement result relating to the light absorption measured by the measurement probe 703 is output to the frequency filter 717, and the frequency component derived from the pulsation of the artery (hereinafter, also simply referred to as “pulsation component”) in the frequency filter 717. To be separated. The information regarding the separated pulsation component is output to the oxygen saturation calculation unit 719, and the oxygen saturation is calculated based on the amplitude of the pulsation component. The calculated oxygen saturation is output to the oxygen saturation output unit 721, and is output to the user by the oxygen saturation output unit 721.

In pulse oximeters, it is required to use light of a plurality of wavelengths as light (incident light) irradiated toward a living body. Therefore, a plurality of light emitting units 711 are arranged on the measurement probe 703 and are used by switching in a time division manner. In addition, for the reason that the incident light easily reaches the living body, light having a wavelength belonging to the band from red light to near-infrared light is often used.

As shown in FIG. 2, the measurement probe 703 of the pulse oximeter 700 irradiates incident light from the light emitting unit 711 onto the skin surface of the living body and reflects the emitted light that is reflected or diffused in the living body, Light is received by the light receiving unit 713. At this time, the incident light is partially absorbed by arteries, veins and other body tissues existing in the living body and is observed as outgoing light.

Here, if the Lambert-Beer law expressed by the following equation 11 holds, the concentration of the substance can be calculated from the intensity ratio of the incident light and the emitted light.

Here, in Equation 11 above,
I ₀ : incident light intensity I ₁ : outgoing light intensity ε: extinction coefficient C: substance concentration l: optical path length

In particular, the absorbance of hemoglobin (Hb) in blood varies depending on the presence or absence of binding to oxygen, and also varies depending on the wavelength to be observed. Therefore, by measuring the absorbance at a plurality of wavelengths, the ratio of hemoglobin (Hb) not bound to oxygen and hemoglobin bound to oxygen (oxygenated hemoglobin: HbO2) can be obtained.

The percentage of oxygenated hemoglobin in the total hemoglobin contained in blood is called blood oxygen saturation. Particularly useful biometric information is arterial oxygen saturation SaO2 (arterial oxygen saturation), and this oxygen saturation SaO2 can be calculated by the following equation (12).

In the above formula 12,
SaO2: arterial blood oxygen saturation C _HbO2 : oxygenated hemoglobin concentration C _Hb : hemoglobin concentration.

Here, the aforementioned SpO2 is obtained by measuring SaO2 transcutaneously. Since SpO2 can be measured non-invasively, it is used in a very wide range, but the problem is how close to the measurement method that can be obtained with a measurement method that performs direct observation. The international standard for pulse oximeters (ISO 9919 2005) stipulates that the error with SaO2 is within 4% when SpO2 is in the range of 70% to 100%.

As described above, the emitted light observed by the light receiving unit 713 of the measurement probe 703 in the pulse oximeter 700 is obtained by the incident light being absorbed by the body tissue and blood components in the process of reflection / scattering in the body. It is possible to calculate SpO2 by analyzing the emitted light intensity, but since SpO2 is the oxygen saturation level of arterial blood, it is required to exclude the influence of light absorption other than from arterial blood from the emitted light.

The elements that cause light absorption in incident light can be broadly classified into three types: arterial blood, venous blood, and other body tissues. At this time, the emitted light receives light absorption as shown in FIG. Equation 13 below is an extension of the Lambert-Beer law shown in Equation 11 above and is called the extended Lambert-Beer rule.

Here, in the above equation 13,
λ: wavelength ε: extinction coefficient C: concentration d: optical path length

In the above equation 13, the first term on the rightmost side represents light absorption caused by components other than blood, and the second term on the rightmost side represents light absorption caused by venous blood. The third term represents light absorption caused by arterial blood, and the fourth term on the rightmost side represents light absorption caused by diffusion in the living body.

The pulse oximeter uses the fact that only the artery is pulsatile among the above three types of elements, and separates the absorption of arterial blood from other elements. That is, the time differentiation of the above expression 13 eliminates the influence of light absorption by veins and other body tissues that do not have pulsatile properties (in other words, no time change). In the signal processing, this differentiation operation corresponds to the removal of the DC component by the frequency filter, and is nothing but the pulse waveform extraction processing.

In the above equation 12, there are two types of unknowns for calculating SaO2: hemoglobin concentration (C _Hb ) and oxygenated hemoglobin concentration (C _HbO2 ). It is required to be coalesced. Therefore, in the pulse oximeter, measurement is performed using at least two wavelengths.

Consider a case in which ΔOD ^λ1 and ΔOD ^λ2 are obtained by measuring with two types of incident light of wavelengths λ1 and λ2 and time-dependent changes in emitted light intensity. In this case, the temporal change in the emitted light intensity measured using the two wavelengths can be expressed as the following Expression 14 from Expression 13 above. Therefore, the unknown hemoglobin concentration (C _Hb ) and oxygenated hemoglobin concentration (C _HbO2 ) are calculated as shown in the following equation 15 using the extinction coefficients of hemoglobin and oxygenated hemoglobin and the measurement results. It becomes possible to do.

Therefore, substituting equation 15 into equation 12, the following equation 16 can be obtained. Here, in the following equation 16, the parameters α, β, and Φ are as the following equations 17a to 17c.

As can be seen from the rightmost side of Equation 16, the value of SaO2 is given as a function proportional to the parameter Φ. The parameter Φ is the ratio of the amplitude of the pulse waveform measured at the wavelength λ1 and the wavelength λ2 as in the above equation 17c. The parameters α and β can be theoretically calculated from the extinction coefficient of hemoglobin as shown in the equations 17a and 17b. However, in many cases, the conversion tables obtained by experiments in advance are used. It is obtained by performing calibration based on By doing so, it is possible to perform correction including the deviation between the condition in which Lambert-Beer's law is established and the condition in the actual living body.

Such a method is the operation principle of the pulse oximeter, and the pulse oximeter calculates the arterial oxygen saturation SpO2 using the measurement results of two wavelengths.

As described above, in a general pulse oximeter, a frequency filter is used to separate a signal corresponding to a pulsating component of an artery, but a signal corresponding to a pulsating component of an artery is clearly separated. Therefore, it is required to use a frequency filter having a steep cutoff characteristic. However, while frequency filter circuits having steep cut-off characteristics tend to be large in scale, if a realistic frequency filter circuit is used to reduce the scale, sufficient separation of pulsation components can be achieved. There was a trade-off relationship that there was a possibility that it could not be done.

Therefore, as a result of intensive studies on the situation as described above, the present inventors have arrived at a measurement apparatus and a measurement method according to an embodiment of the present disclosure as described below, and have a frequency having a steep cutoff characteristic. The arterial pulsation component can be accurately separated without using a filter.

(First embodiment)
<About the configuration of the measuring device>
Hereinafter, the measurement apparatus and the measurement method according to the first embodiment of the present disclosure will be described in detail with reference to FIGS. 4 to 9. FIG. 4 is a block diagram illustrating the configuration of the measurement apparatus according to the present embodiment, and FIGS. 5 and 6 are explanatory diagrams for describing the measurement unit according to the present embodiment. FIG. 7 is a block diagram illustrating the vein position specifying unit according to the present embodiment, and FIG. 8 is a block diagram illustrating the configuration of the pulsation component separating unit according to the present embodiment. FIG. 9 is an explanatory diagram showing the relationship between the skin tissue of the living body and the absorbance in the measuring apparatus according to the present embodiment.

As shown in FIG. 4, the measurement apparatus 10 according to the present embodiment includes a measurement unit 101, a measurement control unit 103, a measurement data acquisition unit 105, a vein position specifying unit 107, a pulsation component separation unit 109, The oxygen saturation calculation unit 111, the measurement result output unit 113, and the storage unit 115 are mainly provided.

The measurement unit 101 according to the present embodiment functions as a measurement probe that measures at least a part of a living body. The measurement unit 101 according to the present embodiment irradiates at least a part of a living body with light of a predetermined wavelength, images the living body with an image sensor, and measures the degree of light absorption by the living body.

As shown in FIG. 5, for example, the measurement unit 101 transmits at least two types of measurement light, that is, red light having a predetermined wavelength (for example, around 660 nm) and near infrared light (for example, around 940 nm) toward the living body. And a plurality of sensors regularly arranged in a predetermined arrangement, and a detection unit (for example, an image) that detects measurement light emitted from the light source unit and transmitted through the living body. Sensor).

The light source unit of the measurement unit 101 irradiates a part of the living body (measurement site) with each of red light and near infrared light as incident light, and captures a skin image of the measurement site. When incident light is applied to the skin, the incident light is reflected and diffused in the living body, and then is emitted as emitted light from the surface of the living body, and is detected by a detection unit having an image sensor. At this time, since the incident light is partially absorbed by an artery, vein, or other biological tissue, the amount of emitted light is smaller than the amount of incident light. A detection part measures distribution of the light quantity of emitted light, and makes it measurement data regarding a measurement part.

As an optical system for imaging the measurement site, an optical system that can perform imaging while being in close contact with the body surface is desirable in order to avoid the influence of the positional deviation of the image sensor and the change in distance from the living body. An example of such an optical system is a microlens array (MLA) optical system as shown in FIG. When the MLA optical system as shown in FIG. 6 is used in combination with incident light having an appropriate wavelength, in-vivo imaging can be performed with the image sensor in close contact with the body surface.

Hereinafter, the configuration of a microlens array optical system which is an example of the measurement unit 101 according to the present embodiment will be specifically described with reference to FIG.

About light source The light source 121 is used to measure a measurement site of a living body, and emits measurement light belonging to a predetermined wavelength band toward the surface of the living body. The light source 121 is disposed on a predetermined frame F such that the measurement light exit surface faces the living body surface.

As described above, the light source 121 is a red light (for example, red light having a wavelength of 660 nm) used for measuring hemoglobin (reduced hemoglobin) or a near-infrared light (for example, used for measuring oxygenated hemoglobin). For example, near-infrared light having a wavelength of 940 nm is emitted. Such light having a plurality of wavelengths is emitted from the light source 121 in a time division manner, for example.

Note that the wavelengths of the red light and near infrared light described above are merely examples, and the light emitted from the light source 121 of the measurement apparatus 10 according to the present embodiment is not limited to the above example.

As such a light source 121, for example, a light emitting diode (LED), a small laser, or the like can be used, and one or a plurality of such light emitting devices are provided as the light source 121.

In the light source 121, the measurement control unit 103 described later controls the emission timing of the measurement light, the intensity of the measurement light emitted, and the like.

The shape of the frame F in which the light source 121 is disposed is not particularly limited, but by providing a wall as shown in FIG. 6 between the light source 121 and a detection unit described later, Such a wall portion can be used as a light shielding wall for preventing light emitted from the light source 121 from entering the detection portion.

Regarding the detection unit The detection unit included in the measurement apparatus 10 according to the present embodiment includes a plurality of sensors regularly arranged in a predetermined arrangement, and a plurality of measurement lights emitted from the light source 121 and transmitted through the living body. This is detected by the sensor. In other words, the detection unit according to the present embodiment is configured by a so-called multi-tap sensor.

As shown in FIG. 6, the detection unit included in the measurement apparatus 10 according to the present embodiment includes, for example, a transparent substrate 123 that can transmit light in a wavelength band to which measurement light emitted from the light source 121 belongs, and a first light shielding. The body 125, the microlens array 127, the second light shield 131, and the sensor 133 are mainly provided.

The transparent substrate 123 is a part where a part of the living body surface is disposed. The transparent substrate 123 is formed using a substrate that can transmit light having a wavelength used in the measurement process. When the measurement light emitted from the light source 121 and transmitted through the living body passes through the transparent substrate 123, the directivity is controlled by the first light shield 125.

The first light shield 125 functions as a directivity control plate that controls the directivity of the measurement light transmitted through the transparent substrate 123, and is provided at the boundary between adjacent microlenses 129 in the microlens array 127 described later. It has been. By providing such a first light shield 125, the directivity of the measurement light incident on each microlens 129 can be controlled, and more accurate measurement can be performed. The measurement light that has passed through the first light shield 125 is guided to the microlens array 127.

As shown in the upper part of FIG. 6, the microlens array 127 is composed of a plurality of microlenses 129 that are light receiving lenses, and each microlens 129 is a lattice on a predetermined substrate along the x and y directions. Are arranged in a shape. Each microlens 129 guides the measurement light incident on the microlens 129 to a sensor 133 described later. Since the microlens array 127 is a lens array with a small curvature of field and no distortion in the depth direction, good measurement data can be obtained by using such a microlens array 129. Note that the depth of field of each microlens 129 constituting the microlens array 127 includes the skin structure to which attention is paid by the measuring apparatus 10 according to the present embodiment (for example, a depth range of 10 mm from the body surface). Up to focus).

Note that the number of microlenses 129 arranged in the microlens array 127 according to the present embodiment is not limited to the example shown in the upper part of FIG. The number of microlenses 129 arranged in the microlens array 127 according to the present embodiment can be freely set according to the size of a living body to be imaged and the size of the sensor 133.

The measurement light incident on the microlens array 127 is condensed by the microlens 129 and imaged on a sensor 133 described later.

Here, on the surface of the microlens array 127 located on the sensor 133 side, the second light shield 131 is provided at the boundary between the microlenses 129 adjacent to each other. The second light shield 131 can control the directivity of the measurement light transmitted through the microlens array 127 and separates the light incident on each microlens 129 from the light incident on the adjacent microlens 129. be able to. Thereby, in the measuring apparatus 10 according to the present embodiment, it is possible to select measurement light condensed on the sensor 133.

The sensor 133 detects the intensity of the measurement light at each position on the xy plane shown in the upper part of FIG. This sensor 133 converts the intensity of measurement light received by a photo detector (PD) or the like into an electrical signal and outputs it to a measurement data acquisition unit 105 described later. As this sensor 133, a CCD (Charge Coupled Devices) type image sensor, a CMOS (Complementary Metal Oxide Semiconductor) type image sensor, a sensor using an organic EL as a light receiving element, a TFT (Thin Film Transistor) type image sensor, or the like. An area sensor can be used.

The scanning timing of the sensor 133 is controlled by the measurement control unit 103 described later, and for example, the detection intensity at an arbitrary position in the upper part of FIG. 6 can be output to the measurement data acquisition unit 105.

The example of the configuration of the measurement unit 101 according to the present embodiment has been described in detail above with reference to FIG.

In the microlens array optical system as described above, each microlens forms a small image in a small area of the light receiving element array immediately below. Since these images have overlapping portions with surrounding images, one complete image without overlapping can be obtained by reconstructing by removing unnecessary portions. The image processing of the MLA optical system has a feature that, when performing this reconstruction, it is possible to generate images focused on different distances by changing the area extracted from the original image. That is, it is possible to focus on a subcutaneous tissue (for example, venous tissue) existing at a depth of several millimeters from the body surface without moving the mechanical optical system while being in close contact with the body surface. Is good. Since the artery is deep in the body and is strongly influenced by light diffusion, an image is not formed and is observed only as a light absorption change over a wide area due to the pulsation of arterial blood.

By using an image sensor provided with the microlens array optical system as described above as the measurement unit 101, the measurement apparatus 10 can be reduced in size. Further, by using the microlens array optical system, it is possible to image a finer blood vessel (vein), and it is possible to improve processing accuracy in the pulsation component separation unit 109 described later.

The measurement unit 101 according to the present embodiment has been described in detail above with reference to FIGS. 5 and 6.
Hereinafter, returning to FIG. 4 again, the measurement control unit 103 according to the present embodiment will be described.

The measurement control unit 103 is realized by, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a communication device, and the like. The measurement control unit 103 controls the whole living body measurement process in the measurement unit 101 by performing drive control of the light source unit and the detection unit provided in the measurement unit 101. More specifically, the measurement control unit 103 performs sensor drive control such as scanning timing of the image sensor used in the detection unit and selection of pixels of the image sensor for acquiring information based on a predetermined synchronization signal or the like. Do. The measurement control unit 103 also performs drive control on the emission timing and intensity of the measurement light for the light source unit.

When the measurement control unit 103 performs the drive control as described above, the light source unit of the measurement unit 101 can emit measurement light having different wavelengths in a time division manner, and the detection unit of the measurement unit 101 can Measurement data at an arbitrary position on the image sensor can be acquired in a time division manner.

Measurement data measured by the measurement unit 101 whose drive is controlled by the measurement control unit 103 is output to a measurement data acquisition unit 105 described later, and measurement data analysis processing is performed.

Here, when controlling the measurement unit 101, the measurement control unit 103 can refer to various programs, parameters, databases, and the like recorded in the storage unit 115 and the like which will be described later.

The measurement data acquisition unit 105 is realized by, for example, a CPU, a ROM, a RAM, a communication device, and the like. The measurement data acquisition unit 105 acquires measurement data measured by the measurement unit 101 (imaging data of a measurement site imaged using light of a predetermined wavelength) from the measurement unit 101, and a later-described vein position specifying unit 107 and Output to the pulsating component separation unit 109. The measurement data acquisition unit 105 sequentially acquires the measurement data output from the measurement unit 101 at every predetermined timing, so that the pulsation component separation unit 109 and the oxygen saturation calculation unit 111 described later change the measurement data over time. Can be grasped.

Note that the measurement data acquisition unit 105 may store the acquired measurement data in the storage unit 115 described later as history information in association with time information regarding the date and time when the data was acquired.

The vein position specifying unit 107 is realized by, for example, a CPU, a ROM, a RAM, and the like. The vein position specifying unit 107 uses the measurement data measured by the measuring unit 101 to specify the position of the vein existing inside the living body at the measurement site of the living body.

The measurement light emitted from the light source unit provided in the measurement unit 101 and entering the inside of the body is scattered inside the body and reaches the detection unit. However, light absorption by venous blood occurs at a position where a vein in the living body exists. Thus, the intensity of light emitted from the living body is reduced. Therefore, in the imaging data measured by the measurement unit 101, the position corresponding to the vein exists as an area having lower luminance than the surroundings. Hereinafter, an image showing the shape of the vein represented in the imaging data is referred to as a vein pattern.

The vein position specifying unit 107 according to the present embodiment includes, for example, a function for performing preprocessing of vein pattern extraction on the measurement data output from the measurement data acquisition unit 105 (that is, the captured image of the measurement site), and the vein It has a function of performing pattern extraction and a function of performing post-processing of vein pattern extraction.

Here, the pre-processing of the vein pattern extraction described above includes, for example, a process of detecting the contour of a finger from a vein image and identifying where the finger is located in the vein image, and using the detected finger contour. This includes processing for rotating the captured image and correcting the angle of the captured image.

In addition, the above-described vein pattern extraction is performed by applying a differential filter to the captured image for which contour detection and angle correction have been completed. The difference filter is a filter that outputs a large value as an output value at a portion where the difference between the pixel of interest and the surrounding pixels is large between the pixel of interest and the surrounding pixels. In other words, the difference filter is a filter that emphasizes lines and edges in an image by calculation using a difference between a pixel of interest and a gradation value in the vicinity thereof.

In general, when filter processing is performed on image data u (x, y) using a lattice point (x, y) on a two-dimensional plane as a variable using a filter h (x, y), the following equation 101 As shown, image data ν (x, y) is generated. Here, in the following formula 101, “*” represents a convolution (convolution).

In the extraction of the vein pattern according to the present embodiment, a differential filter such as a primary spatial differential filter or a secondary spatial differential filter may be used as the differential filter. The primary spatial differential filter is a filter that calculates a difference between gradation values of adjacent pixels in the horizontal direction and the vertical direction for the pixel of interest, and the secondary spatial differential filter is the pixel of interest. Is a filter that extracts a portion where the amount of change in the difference in gradation value is large.

As the secondary spatial differential filter, for example, the following Log (Laplacian of Gaussian) filter can be used. The Log filter (Formula 103) is represented by the second derivative of a Gaussian filter (Formula 102) which is a smoothing filter using a Gaussian function. Here, in the following formula 102, σ represents a standard deviation of the Gaussian function and is a variable representing the degree of smoothing of the Gaussian filter. Also, σ in the following equation 103 is a parameter representing the standard deviation of the Gaussian function as in the equation 102, and changing the value of σ can change the output value when the log filter processing is performed. it can.

Further, the post-processing of the vein pattern extraction described above includes, for example, threshold processing, binarization processing, thinning processing, and the like performed on the captured image after application of the difference filter. Through such post-processing, it is possible to extract a skeleton of a vein pattern.

When the vein pattern is extracted by the method described above, the vein position specifying unit 107 generates information representing the position of the vein existing inside the living body at the measurement site of the living body based on the extracted vein pattern. In the following, the information indicating the position of the vein is referred to as a vein mask.

Hereinafter, the vein mask generated by the vein position specifying unit 107 will be briefly described with reference to FIG.

FIG. 7A is a captured image captured by the measurement unit 101 according to the present embodiment, and FIG. 7B illustrates a vein pattern extracted from the captured image illustrated in FIG. It is a schematic diagram. Referring to FIG. 7 (a), it can be seen that the shape of the veins appears dark. This is because incident light is absorbed by venous blood. Therefore, for example, in the captured image as shown in FIG. 7A, it can be determined that the region where the brightness value is darker than the surroundings is the position where the vein exists.

When the vein position specifying unit 107 according to the present embodiment extracts the vein pattern as illustrated in FIG. 7B using the captured image as illustrated in FIG. As shown in c), the vein pattern is divided into a plurality of small regions. Here, the number of divisions into small areas is not particularly limited, and may be determined as appropriate according to the number of pixels of the captured image, the required measurement accuracy, and the like.

The vein position specifying unit 107 determines whether the average luminance for each small region shown in FIG. 7C is brighter than a predetermined threshold (whether the average luminance is larger than the predetermined threshold), The vein pattern is binarized. That is, the vein position specifying unit 107 treats the pixel value of the small area having the average luminance equal to or higher than the predetermined threshold as 1, and treats the pixel value of the small area having the average luminance less than the predetermined threshold as 0. As shown in FIG. 7D, a binarized image of a vein pattern can be generated. The vein position specifying unit 107 uses such a binarized image of the vein pattern as a vein mask.

When the vein position specifying unit 107 generates the vein mask in this manner, the vein position specifying unit 107 outputs the generated vein mask to the pulsation component separating unit 109 described later.

Note that it is sufficient to generate one vein mask as described above for the first pulse wave measurement. However, two or more vein masks may be generated. The details of the vein pattern extraction processing performed by the vein position specifying unit 107 are not limited to the above processing method, and any known processing method can be used.

Returning to FIG. 4 again, the pulsation component separation unit 109 according to the present embodiment will be described.
The pulsating component separation unit 109 according to the present embodiment is realized by, for example, a CPU, a ROM, a RAM, and the like. The pulsation component separation unit 109 is present in the living body among the time changes of the measurement data based on the time change of the measurement data by the measurement unit 101 and the position of the vein specified by the vein position specifying unit 107. Isolate components derived from arterial pulsations.

The pulsation component separation unit 109 includes a spatial filter unit 141 and a frequency filter unit 143 as shown in FIG.

The spatial filter unit 141 is realized by, for example, a CPU, a ROM, a RAM, and the like. The spatial filter unit 141 corresponds to the vein position from a plurality of measurement data obtained by continuously imaging the measurement site based on the vein position (ie, vein mask) specified by the vein position specifying unit 107. Exclude data. Thereafter, the spatial filter unit 141 excludes the vein part and calculates the average luminance for each measurement data of the light receiving element at the position where there is no vein. By arranging the average luminance calculated in this manner in time series for each image frame, the spatial filter unit 141 causes body tissues other than venous blood (that is, arterial blood and non-venous blood) for each small region as shown in FIG. Absorbance time change data by other body tissues) can be generated.

As shown in FIG. 9, the light absorption measured at a position without a vein is in a state in which a light absorption component derived from venous blood is excluded from the beginning. Since the light received at the position where the vein does not exist is not absorbed by the venous blood, the ratio of the light absorption component of the arterial blood to be measured is relatively large compared to the light received at the position where the vein exists. Become. Therefore, the signal-to-noise ratio (Signal to Noise Ratio: S / N) can be improved by referring to the vein mask image and using measurement data at a position where no vein exists.

Thus, it can be seen that the process of performing the separation based on the spatial position recognized as the vein from the captured image is a process corresponding to the information separation by the spatial filter.

When the spatial filter unit 141 generates the time change data of the absorbance using the vein mask and the measurement data, the spatial filter unit 141 outputs the generated time change data to the frequency filter unit 143 described later.

The frequency filter unit 143 is realized by, for example, a CPU, a ROM, a RAM, and the like. The frequency filter unit 143 separates a predetermined frequency component from the measurement data output from the spatial filter unit 141 and excluding data corresponding to the vein position. Thereby, the frequency filter unit 143 excludes a DC component (that is, a component derived from other body tissue in FIG. 9) from the time change data output from the spatial filter unit 141. The data generated in this way is pulse waveform data representing the pulsation of the artery.

The frequency filter unit 143 outputs the pulse waveform data representing the pulsation of the artery thus generated to the measurement result output unit 113 described later. In the measurement apparatus 10 according to the present embodiment, when the oxygen saturation SpO2 is calculated, the frequency filter unit 143 outputs the generated pulse waveform data to the oxygen saturation calculation unit 111 described later.

As described above, the pulsation component separation unit 109 according to the present embodiment separates the spatial position recognized as a vein on the captured image, and processes the separated data by the frequency filter. As a result, the cutoff frequency characteristic required for the frequency filter can be relaxed, and the pulsation component of the artery can be accurately separated without using a frequency filter having a steep cutoff characteristic.

The frequency filter unit 143 may store the generated pulse waveform data representing the pulsation of the artery in association with time information related to the time when the data is generated, etc., in the storage unit 115 described later as history information. .

The oxygen saturation calculation unit 111 is realized by, for example, a CPU, a ROM, a RAM, and the like. The oxygen saturation calculation unit 111 calculates the oxygen saturation in the arterial blood using a component derived from the pulsation of the artery separated by the pulsation component separation unit 109 (that is, pulse waveform data). More specifically, the oxygen saturation calculation unit 111 includes pulse waveform data generated from measurement data measured using red light, and pulse waveform data generated from measurement data measured using infrared light. And the hemoglobin concentration and the oxygenated hemoglobin concentration are calculated. In addition, the oxygen saturation calculation unit 111 calculates the oxygen saturation using the calculated hemoglobin concentration and oxygenated hemoglobin concentration.

The method for calculating the oxygen saturation is not particularly limited. For example, the oxygen saturation calculating method based on the equations 16 to 17c described above can be used.

When the oxygen saturation calculation unit 111 calculates the oxygen saturation SpO2 using the hemoglobin concentration and the oxygenated hemoglobin concentration calculated using the pulse waveform data, information on the calculated oxygen saturation SpO2 is obtained as a measurement result described later. Output to the output unit 113. The oxygen saturation calculation unit 111 may store information on the calculated oxygen saturation in association with time information such as the date and time when the information is generated in the storage unit 115 described later as history information.

The measurement result output unit 113 is realized by, for example, a CPU, a ROM, a RAM, an output device, a communication device, and the like. The measurement result output unit 113 is obtained by analyzing the pulsation component of the artery such as the pulse waveform data generated by the pulsation component separation unit 109 and the information regarding the oxygen saturation SpO2 calculated by the oxygen saturation calculation unit 111. Outputs feature data and feature values that can be used. The measurement result output unit 113 may output various types of information derived from the arterial pulsation component to an output device such as a display provided in the measurement device 10, or as a paper medium using a printer or the like. You may output to a user. The measurement result output unit 113 may output various information derived from the obtained arterial pulsation component to a display, various information processing apparatuses, and the like provided outside the measurement apparatus 10.

The measurement result output unit 113 outputs various kinds of information derived from the pulsatile component of the artery, so that the user of the measurement apparatus 10 according to the present embodiment can grasp the measurement result.

The storage unit 115 is realized by a RAM, a storage device, or the like provided in the measurement apparatus 10 according to the present embodiment. The storage unit 115 stores optical absorption spectrum data used in various processes in the measuring apparatus 10, such as conversion tables related to the constants α and β shown in Equation 16 above, various databases, lookup tables, and the like. ing. The storage unit 115 stores measurement data measured by the measurement unit 101 according to the present embodiment, various programs, parameters, data, and the like used for processing performed by the measurement apparatus 10 according to the present embodiment. It may be. In addition to these data, the storage unit 115 can appropriately store various parameters that need to be saved when the measurement apparatus 10 performs some processing, the progress of the processing, and the like. . The storage unit 115 includes each process of the measurement unit 101, the measurement control unit 103, the measurement data acquisition unit 105, the vein position specifying unit 107, the pulsation component separation unit 109, the oxygen saturation calculation unit 111, the measurement result output unit 113, and the like. The section can freely access and write and read data.

The configuration of the measurement apparatus 10 according to the present embodiment has been described in detail above with reference to FIGS. 4 to 9.

The measurement control unit 103, the measurement data acquisition unit 105, the vein position specifying unit 107, the pulsation component separation unit 109, the oxygen saturation calculation unit 111, and the measurement result output unit 113 according to this embodiment are related to this embodiment. It may be realized as a part of the measuring apparatus 10 or may be realized in an external device such as a computer connected to the measuring apparatus 10. In addition, measurement data generated by the measurement unit 101 is stored in a removable storage medium or the like, and this storage medium is removed from the measurement apparatus 10, and the measurement data acquisition unit 105, vein position specifying unit 107, and pulsation component separation unit 109 are removed. The measurement data may be analyzed by being connected to another device having the oxygen saturation calculation unit 111 and the measurement result output unit 113.

Heretofore, an example of the function of the measuring apparatus 10 according to the present embodiment has been shown. Each component described above may be configured using a general-purpose member or circuit, or may be configured by hardware specialized for the function of each component. In addition, the CPU or the like may perform all functions of each component. Therefore, it is possible to appropriately change the configuration to be used according to the technical level at the time of carrying out the present embodiment.

It should be noted that a computer program for realizing each function of the measuring apparatus according to the present embodiment as described above can be produced and mounted on a personal computer or the like. In addition, a computer-readable recording medium storing such a computer program can be provided. The recording medium is, for example, a magnetic disk, an optical disk, a magneto-optical disk, a flash memory, or the like. Further, the above computer program may be distributed via a network, for example, without using a recording medium.

<About measurement method>
Subsequently, the flow of the measurement method performed by the measurement apparatus 10 according to the present embodiment will be described in detail with reference to FIGS. FIG. 10 is a flowchart showing an example of the overall flow of the measurement method according to the present embodiment. FIG. 11 is a flowchart illustrating an example of a flow of vein mask generation processing according to the present embodiment, and FIG. 12 is a flowchart illustrating an example of a flow of vein mask application processing according to the present embodiment.

[Overall flow of measurement method]
First, the overall flow of the measurement method according to the present embodiment will be described with reference to FIG.
First, the measurement unit 101 of the measurement apparatus 10 according to the present embodiment measures a measurement site of a living body placed on the measurement unit 101 under the control of the measurement control unit 103 (step S101), and creates a vein mask. An initial image (vein mask image) is acquired (step S103). The measurement unit 101 outputs the obtained vein mask image to the measurement data acquisition unit 105, and the measurement data acquisition unit 105 outputs the output vein mask image to the vein position specifying unit 107.

The vein position specifying unit 107 generates a vein mask based on the vein mask image output from the measurement data acquisition unit 105 (step S105). After generating the vein mask, the vein position specifying unit 107 outputs the generated vein mask to the pulsation component separating unit 109.

Thereafter, the measurement unit 101 of the measurement apparatus 10 according to the present embodiment acquires initial measurement data (image data) for pulse wave measurement under the control of the measurement control unit 103 (step S107). Thereafter, the measurement unit 101 outputs the obtained image to the measurement data acquisition unit 105, and the measurement data acquisition unit 105 outputs the output measurement data (image data) to the pulsation component separation unit 109.

The spatial filter unit 141 of the pulsation component separation unit 109 applies the vein mask generated by the vein position specifying unit 105 to the image output from the measurement data acquisition unit 107 (step S109), and there is a vein. The measurement data excluding the position to be generated is generated. Thereafter, the spatial filter unit 141 calculates an average luminance value using the obtained data, and outputs the obtained average luminance value data to the frequency filter unit 143.

The frequency filter unit 143 applies a frequency filter to the time series of the average luminance value data output from the spatial filter unit 141 (step S111), removes the DC component, and then obtains the obtained data (ie, Pulse waveform data) is output to the oxygen saturation calculator 111.

Here, the measurement control unit 103 determines whether or not the measurement has been performed for a desired measurement time (step S113), and when the measurement for the desired measurement time has not been completed, the measurement unit 101 receives the next measurement time. An image is acquired (step S115). When the measurement unit 101 acquires the next image, the measurement unit 101 outputs the acquired image to the measurement data acquisition unit 105, and the measurement data acquisition unit 105 outputs the acquired data to the pulsation component separation unit 109. Thereafter, the pulsation component separation unit 109 continues to perform the processing from step S109.

On the other hand, when the measurement for the desired measurement time has been completed, the oxygen saturation calculation unit 111 calculates the oxygen saturation based on the time-series transition of the obtained pulse waveform data (step S117). ). Thereafter, the oxygen saturation calculation unit 111 outputs information on the obtained oxygen saturation to the measurement result output unit 113.

By performing the processing as described above, the measurement apparatus 10 according to the present embodiment can measure the pulse waveform data at the measurement site and calculate the oxygen saturation.

[Venous mask generation processing]
Next, the flow of the vein mask image generation process performed by the vein position specifying unit 107 will be briefly described with reference to FIG.
The vein position specifying unit 107 first divides the vein mask image output from the measurement data acquisition unit 105 into a plurality of small regions (step S121). Thereafter, the vein position specifying unit 107 selects the first small area (step S123), and integrates the luminance value of each pixel in the selected small area.

Next, the vein position specifying unit 107 compares the luminance value obtained by the integration with a predetermined threshold value set in advance (step S125). When the luminance value obtained by the integration is equal to or greater than a predetermined threshold, the vein position specifying unit 107 is an area where the selected small area receives light absorption by the vein (hereinafter also referred to as a vein area). (Step S129). On the other hand, when the luminance value obtained by integration is less than the predetermined threshold, the vein position specifying unit 107 determines that the selected small region is not affected by the vein (hereinafter also referred to as a non-venous region). .)) (Step S131).

Thereafter, the vein position specifying unit 107 determines whether or not processing has been performed on all the small regions (step S133). If the processing has not been performed for all the small regions, the vein position specifying unit 107 selects the next small region (steps S1359 and S125 are performed again. On the other hand, for all the small regions, If the process is executed, it is determined that the vein mask image has been generated, and the process ends.

[Venous mask application processing]
Next, the flow of the vein mask image application processing performed by the spatial filter unit 141 will be briefly described with reference to FIG.
The application process of the vein mask performed by the spatial filter unit 141 is a process of measuring the average luminance for each image using a plurality of measurement data (image data) obtained by continuously photographing the vein mask and the measurement site. is there. Specifically, the spatial filter unit 141 performs the following operation for each image frame obtained by continuous shooting.

First, the spatial filter unit 141 divides the image data output from the measurement data acquisition unit 105 into a plurality of small regions (step S141). Thereafter, the spatial filter unit 141 selects the first small region among the plurality of small regions (step S143).

Subsequently, the spatial filter unit 141 refers to the vein mask output from the vein position specifying unit 107 and determines whether or not the selected small region is marked as a vein region (step S145). If the selected small region is not a vein region, the spatial filter unit 141 integrates the luminance value of each pixel in the selected small region (step S147), and then converts the integrated luminance value to the overall luminance value. Integration is performed (step S149). On the other hand, when the selected small region is a vein region, the spatial filter unit 141 performs step S151 described later without performing steps S147 and S149.

Next, the spatial filter unit 141 determines whether or not processing has been performed on all the small regions (step S151). If the processing has not been performed for all the small regions, the spatial filter unit 141 selects the next small region (step S153) and performs the above step S145 again. On the other hand, when processing is performed on all the small regions, the spatial filter unit 141 divides the overall luminance value by the total number of pixels used for integration. As a result, normalization is performed on the average luminance value per pixel regardless of the number of vein regions in the vein mask (step S155). The spatial filter unit 141 calculates the average luminance value per pixel of each image frame by performing the above processing.

A configuration in which no division for normalization is performed in step S155 is also conceivable. In this case, the outputs of a plurality of light receiving elements are added, and the effect that the light receiving area increases and the sensitivity becomes high can be obtained.

The flow of the measurement method performed by the measurement apparatus 10 according to the present embodiment has been described above with reference to FIGS. 10 to 12.

(About hardware configuration)
Next, the hardware configuration of the measurement apparatus 10 according to the embodiment of the present disclosure will be described in detail with reference to FIG. FIG. 13 is a block diagram for explaining a hardware configuration of the measurement apparatus 10 according to the embodiment of the present disclosure.

The measuring apparatus 10 mainly includes a CPU 901, a ROM 903, and a RAM 905. The measurement apparatus 10 further includes a host bus 907, a bridge 909, an external bus 911, an interface 913, a sensor 914, an input device 915, an output device 917, a storage device 919, a drive 921, a connection port 923, and a communication device 925. .

The CPU 901 functions as an arithmetic processing device and a control device, and controls all or a part of the operation in the measuring device 10 according to various programs recorded in the ROM 903, the RAM 905, the storage device 919, or the removable recording medium 927. The ROM 903 stores programs used by the CPU 901, calculation parameters, and the like. The RAM 905 primarily stores programs used by the CPU 901, parameters that change as appropriate during execution of the programs, and the like. These are connected to each other by a host bus 907 constituted by an internal bus such as a CPU bus.

The host bus 907 is connected to an external bus 911 such as a PCI (Peripheral Component Interconnect / Interface) bus via a bridge 909.

The sensor 914 is, for example, detection means for detecting biological information unique to the user or various information used for acquiring such biological information. Examples of the sensor 914 include various image pickup devices such as a CCD (Charge Coupled Device) and a CMOS (Complementary Metal Oxide Semiconductor). The sensor 914 may further include an optical system such as a lens and a light source used for imaging a living body part. The sensor 914 may be a microphone or the like for acquiring sound or the like. The sensor 914 may include various measuring devices such as a thermometer, an illuminometer, a hygrometer, a speedometer, and an accelerometer in addition to the above-described ones.

The input device 915 is an operation means operated by the user such as a mouse, a keyboard, a touch panel, a button, a switch, and a lever. Further, the input device 915 may be, for example, remote control means (so-called remote control) using infrared rays or other radio waves, or an external connection device 929 such as a mobile phone or a PDA corresponding to the operation of the measuring device 10. It may be. Furthermore, the input device 915 includes an input control circuit that generates an input signal based on information input by a user using the above-described operation means and outputs the input signal to the CPU 901, for example. The user of the measuring device 10 can input various data and instruct processing operations to the measuring device 10 by operating the input device 915.

The output device 917 is a device that can notify the user of the acquired information visually or audibly. Examples of such devices include CRT display devices, liquid crystal display devices, plasma display devices, EL display devices and display devices such as lamps, audio output devices such as speakers and headphones, printer devices, mobile phones, and facsimiles. The output device 917 outputs, for example, results obtained by various processes performed by the measurement device 10. Specifically, the display device displays the results obtained by various processes performed by the measurement device 10 as text or images. On the other hand, the audio output device converts an audio signal composed of reproduced audio data, acoustic data, and the like into an analog signal and outputs the analog signal.

The storage device 919 is a data storage device configured as an example of a storage unit of the measurement device 10. The storage device 919 includes, for example, a magnetic storage device such as an HDD (Hard Disk Drive), a semiconductor storage device, an optical storage device, or a magneto-optical storage device. The storage device 919 stores programs executed by the CPU 901, various data, various data acquired from the outside, and the like.

The drive 921 is a reader / writer for a recording medium, and is built in or externally attached to the measuring apparatus 10. The drive 921 reads information recorded on a removable recording medium 927 such as a mounted magnetic disk, optical disk, magneto-optical disk, or semiconductor memory, and outputs the information to the RAM 905. In addition, the drive 921 can write a record on a removable recording medium 927 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory. The removable recording medium 927 is, for example, a DVD medium, an HD-DVD medium, a Blu-ray medium, or the like. The removable recording medium 927 may be a compact flash (registered trademark) (CompactFlash: CF), a flash memory, or an SD memory card (Secure Digital memory card). Further, the removable recording medium 927 may be, for example, an IC card (Integrated Circuit card) on which a non-contact IC chip is mounted, an electronic device, or the like.

The connection port 923 is a port for directly connecting a device to the measurement apparatus 10. Examples of the connection port 923 include a USB (Universal Serial Bus) port, an IEEE 1394 port, a SCSI (Small Computer System Interface) port, and the like. As another example of the connection port 923, there are an RS-232C port, an optical audio terminal, an HDMI (High-Definition Multimedia Interface) port, and the like. By connecting the external connection device 929 to the connection port 923, the measurement apparatus 10 acquires various data directly from the external connection device 929 or provides various data to the external connection device 929.

The communication device 925 is a communication interface configured with, for example, a communication device for connecting to the communication network 931. The communication device 925 is, for example, a communication card for a wired or wireless LAN (Local Area Network), Bluetooth (registered trademark), or WUSB (Wireless USB). The communication device 925 may be a router for optical communication, a router for ADSL (Asymmetric Digital Subscriber Line), or a modem for various communication. The communication device 925 can transmit and receive signals and the like according to a predetermined protocol such as TCP / IP, for example, with the Internet or other communication devices. The communication network 931 connected to the communication device 925 is configured by a wired or wireless network, and may be, for example, the Internet, a home LAN, infrared communication, radio wave communication, satellite communication, or the like. .

Heretofore, an example of the hardware configuration capable of realizing the function of the measurement apparatus 10 according to the embodiment of the present disclosure has been shown. Each component described above may be configured using a general-purpose member, or may be configured by hardware specialized for the function of each component. Therefore, it is possible to change the hardware configuration to be used as appropriate according to the technical level at the time of carrying out this embodiment.

(Summary)
As described above, in the embodiment of the present disclosure, by using only information acquired by a light receiving element at a position where a vein does not exist based on a vein pattern image, a light absorption component due to venous blood from the beginning is obtained. The excluded data having a higher signal-to-noise ratio can be input to the frequency filter. That is, the cut-off frequency characteristic required for the frequency filter can be relaxed by adopting a method in which data obtained by previously separating information separable by the spatial filter is input to the frequency filter. As a result, even when a frequency filter having a simpler configuration is used, excellent pulsation component separation processing (pulse waveform separation processing) can be realized.

The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, but the technical scope of the present disclosure is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field of the present disclosure can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that it belongs to the technical scope of the present disclosure.

The following configurations also belong to the technical scope of the present disclosure.
(1)
A measurement unit that irradiates at least a part of the living body with light of a predetermined wavelength, images the living body with an image sensor, and measures the degree of absorption of the light by the living body;
Utilizing measurement data by the measurement unit, a vein position specifying unit that specifies a position corresponding to a vein existing inside the living body at the measurement site of the living body;
Based on the time change of the measurement data by the measurement unit and the position of the vein specified by the vein position specifying unit, the pulsation of an artery existing inside the living body among the time change of the measurement data is determined. A pulsating component separation unit that separates components derived from;
Using a component derived from the pulsation of the artery of the measurement data separated by the pulsation component separation unit, an oxygen saturation calculation unit for calculating oxygen saturation in arterial blood;
A measuring device.
(2)
The pulsating component separation unit is
A spatial filter unit for excluding data corresponding to the position of the vein from the measurement data based on the position of the vein specified by the vein position specifying unit;
A frequency filter unit that separates a predetermined frequency component from the measurement data from which data corresponding to the position of the vein is excluded;
The measuring device according to (1).
(3)
The measuring unit is
A light source unit that emits at least two types of measurement light of red light and infrared light having a predetermined wavelength toward the living body;
A plurality of sensors are regularly arranged in a predetermined arrangement, and a detection unit that detects measurement light emitted from the light source unit and transmitted through the living body with the plurality of sensors,
The measuring device according to (1) or (2).
(4)
The measurement device according to (3), wherein the detection unit detects measurement light transmitted through the living body by a sensor using a microlens array in which a plurality of lenses are regularly arranged in a lattice shape.
(5)
The oxygen saturation calculation unit calculates the hemoglobin concentration and the oxygenated hemoglobin concentration using the measurement data measured using the red light and the measurement data measured using the infrared light. The measurement apparatus according to (3) or (4), wherein the oxygen saturation is calculated using the calculated hemoglobin concentration and oxygenated hemoglobin concentration.
(6)
Irradiating at least a part of the living body with light of a predetermined wavelength, imaging the living body with an image sensor, and measuring the degree of absorption of the light by the living body;
Using the measured measurement data, specifying a position corresponding to a vein existing inside the living body at the measurement site of the living body;
Separating a component derived from the pulsation of an artery present inside the living body from the time change of the measurement data based on the time change of the measurement data and the specified position of the vein;
Using a component derived from the arterial pulsation of the separated measurement data to calculate oxygen saturation in arterial blood;
Including a measuring method.
(7)
A computer capable of communicating with a measurement unit that irradiates at least a part of a living body with light of a predetermined wavelength, images the living body with an image sensor, and measures the degree of absorption of the light by the living body.
Utilizing measurement data by the measurement unit, a vein position specifying function for specifying a position corresponding to a vein existing inside the living body at the measurement site of the living body;
Based on the time change of the measurement data by the measurement unit and the position of the vein specified by the vein position specifying function, the pulsation of the artery existing inside the living body among the time change of the measurement data is determined. Pulsation component separation function to separate the derived components,
An oxygen saturation calculation function for calculating oxygen saturation in arterial blood using a component derived from the pulsation of the artery of the measurement data separated by the pulsation component separation function;
A program to realize
(8)
A computer capable of communicating with a measurement unit that irradiates at least a part of a living body with light of a predetermined wavelength, images the living body with an image sensor, and measures the degree of absorption of the light by the living body.
Utilizing measurement data by the measurement unit, a vein position specifying function for specifying a position corresponding to a vein existing inside the living body at the measurement site of the living body;
Based on the time change of the measurement data by the measurement unit and the position of the vein specified by the vein position specifying function, the pulsation of the artery existing inside the living body among the time change of the measurement data is determined. Pulsation component separation function to separate the derived components,
An oxygen saturation calculation function for calculating oxygen saturation in arterial blood using a component derived from the pulsation of the artery of the measurement data separated by the pulsation component separation function;
A recording medium on which a program for realizing the above is recorded.
(9)
A measurement unit that irradiates at least a part of the living body with light of a predetermined wavelength, images the living body with an image sensor, and measures the degree of absorption of the light by the living body;
Utilizing measurement data by the measurement unit, a vein position specifying unit that specifies a position corresponding to a vein existing inside the living body at the measurement site of the living body;
Based on the time change of the measurement data by the measurement unit and the position of the vein specified by the vein position specifying unit, the pulsation of an artery existing inside the living body among the time change of the measurement data is determined. A pulsating component separation unit that separates components derived from;
Using a component derived from the pulsation of the artery of the measurement data separated by the pulsation component separation unit, an oxygen saturation calculation unit for calculating oxygen saturation in arterial blood;
With
The measuring unit is
A light source unit that emits at least two types of measurement light of red light and infrared light having a predetermined wavelength toward the living body;
A plurality of sensors are regularly arranged in a predetermined arrangement, and a detection unit that detects measurement light emitted from the light source unit and transmitted through the living body with the plurality of sensors,
A measuring device.
(10)
Irradiating at least a part of the living body with light of a predetermined wavelength, imaging the living body with an image sensor, and measuring the degree of absorption of the light by the living body;
Using the measured measurement data, specifying a position corresponding to a vein existing inside the living body at the measurement site of the living body;
Separating a component derived from the pulsation of an artery present inside the living body from the time change of the measurement data based on the time change of the measurement data and the specified position of the vein;
Using a component derived from the arterial pulsation of the separated measurement data to calculate oxygen saturation in arterial blood;
Including
When measuring the degree of light absorption,
At least two kinds of measurement light of red light and infrared light having a predetermined wavelength are emitted toward the living body, and the plurality of sensors are transmitted through the living body by sensors regularly arranged in a predetermined arrangement. A measurement method that detects measurement light.

DESCRIPTION OF SYMBOLS 10 Measuring apparatus 101 Measuring part 103 Measurement control part 105 Measurement data acquisition part 107 Vein position specific | specification part 109 Pulsatile component separation part 111 Oxygen saturation calculation part 113 Measurement result output part 115 Storage part

Claims

A measurement unit that irradiates at least a part of the living body with light of a predetermined wavelength, images the living body with an image sensor, and measures the degree of absorption of the light by the living body;
Utilizing measurement data by the measurement unit, a vein position specifying unit that specifies a position corresponding to a vein existing inside the living body at the measurement site of the living body;
Based on the time change of the measurement data by the measurement unit and the position of the vein specified by the vein position specifying unit, the pulsation of an artery existing inside the living body among the time change of the measurement data is determined. A pulsating component separation unit that separates components derived from;
Using a component derived from the pulsation of the artery of the measurement data separated by the pulsation component separation unit, an oxygen saturation calculation unit for calculating oxygen saturation in arterial blood;
A measuring device.
The pulsating component separation unit is
A spatial filter unit for excluding data corresponding to the position of the vein from the measurement data based on the position of the vein specified by the vein position specifying unit;
A frequency filter unit that separates a predetermined frequency component from the measurement data from which data corresponding to the position of the vein is excluded;
The measuring apparatus according to claim 1, comprising:
The measuring unit is
A light source unit that emits at least two types of measurement light of red light and infrared light having a predetermined wavelength toward the living body;
A plurality of sensors are regularly arranged in a predetermined arrangement, and a detection unit that detects measurement light emitted from the light source unit and transmitted through the living body with the plurality of sensors,
The measurement apparatus according to claim 2, comprising:
The measurement device according to claim 3, wherein the detection unit detects measurement light transmitted through the living body by a sensor using a microlens array in which a plurality of lenses are regularly arranged in a lattice shape.
The oxygen saturation calculation unit calculates the hemoglobin concentration and the oxygenated hemoglobin concentration using the measurement data measured using the red light and the measurement data measured using the infrared light. The measurement apparatus according to claim 4, wherein the oxygen saturation is calculated using the calculated hemoglobin concentration and oxygenated hemoglobin concentration.
Irradiating at least a part of the living body with light of a predetermined wavelength, imaging the living body with an image sensor, and measuring the degree of absorption of the light by the living body;
Using the measured measurement data, specifying a position corresponding to a vein existing inside the living body at the measurement site of the living body;
Separating a component derived from the pulsation of an artery present inside the living body from the time change of the measurement data based on the time change of the measurement data and the specified position of the vein;
Using a component derived from the arterial pulsation of the separated measurement data to calculate oxygen saturation in arterial blood;
Including a measuring method.
A computer capable of communicating with a measurement unit that irradiates at least a part of a living body with light of a predetermined wavelength, images the living body with an image sensor, and measures the degree of absorption of the light by the living body.
Utilizing measurement data by the measurement unit, a vein position specifying function for specifying a position corresponding to a vein existing inside the living body at the measurement site of the living body;
Based on the time change of the measurement data by the measurement unit and the position of the vein specified by the vein position specifying function, the pulsation of the artery existing inside the living body among the time change of the measurement data is determined. Pulsation component separation function to separate the derived components,
An oxygen saturation calculation function for calculating oxygen saturation in arterial blood using a component derived from the pulsation of the artery of the measurement data separated by the pulsation component separation function;
A program to realize
A computer capable of communicating with a measurement unit that irradiates at least a part of a living body with light of a predetermined wavelength, images the living body with an image sensor, and measures the degree of absorption of the light by the living body.
Utilizing measurement data by the measurement unit, a vein position specifying function for specifying a position corresponding to a vein existing inside the living body at the measurement site of the living body;
Based on the time change of the measurement data by the measurement unit and the position of the vein specified by the vein position specifying function, the pulsation of the artery existing inside the living body among the time change of the measurement data is determined. Pulsation component separation function to separate the derived components,
An oxygen saturation calculation function for calculating oxygen saturation in arterial blood using a component derived from the pulsation of the artery of the measurement data separated by the pulsation component separation function;
A recording medium on which a program for realizing the above is recorded.
A measurement unit that irradiates at least a part of the living body with light of a predetermined wavelength, images the living body with an image sensor, and measures the degree of absorption of the light by the living body;
Utilizing measurement data by the measurement unit, a vein position specifying unit that specifies a position corresponding to a vein existing inside the living body at the measurement site of the living body;
Based on the time change of the measurement data by the measurement unit and the position of the vein specified by the vein position specifying unit, the pulsation of an artery existing inside the living body among the time change of the measurement data is determined. A pulsating component separation unit that separates components derived from;
Using a component derived from the pulsation of the artery of the measurement data separated by the pulsation component separation unit, an oxygen saturation calculation unit for calculating oxygen saturation in arterial blood;
With
The measuring unit is
A light source unit that emits at least two types of measurement light of red light and infrared light having a predetermined wavelength toward the living body;
A plurality of sensors are regularly arranged in a predetermined arrangement, and a detection unit that detects measurement light emitted from the light source unit and transmitted through the living body with the plurality of sensors,
A measuring device.
Irradiating at least a part of the living body with light of a predetermined wavelength, imaging the living body with an image sensor, and measuring the degree of absorption of the light by the living body;
Using the measured measurement data, specifying a position corresponding to a vein existing inside the living body at the measurement site of the living body;
Separating a component derived from the pulsation of an artery present inside the living body from the time change of the measurement data based on the time change of the measurement data and the specified position of the vein;
Using a component derived from the arterial pulsation of the separated measurement data to calculate oxygen saturation in arterial blood;
Including
When measuring the degree of light absorption,
At least two kinds of measurement light of red light and infrared light having a predetermined wavelength are emitted toward the living body, and the plurality of sensors are transmitted through the living body by sensors regularly arranged in a predetermined arrangement. A measurement method that detects measurement light.