Apparatus and method for measuring biological signal

Provided are apparatuses for and methods of measuring a biological signal. The biological signal measuring apparatus includes reference point sensors configured to detect signals detected from at least two reference marks on a surface of a subject and a biological signal measuring position detector configured to generate information about a biological signal measuring position based on the signals detected from the at least two reference marks. The biological signal measuring apparatus measures the biological signal according to the information about the biological signal measuring position.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Korean Patent Application No. 10-2015-0002025, filed on Jan. 7, 2015 in the Korean Intellectual Property Office, the disclosures of which is incorporated herein in its entirety by reference.

BACKGROUND

Apparatuses and methods consistent with exemplary embodiments relate to measuring a biological signal, whereby a measuring position of a biological signal may be detected.

2. Description of the Related Art

Along with the advances in medical science and the increase of the average life expectancy, the interest in health care and related medical devices has also increased. In addition, the interest in small-and medium-sized medical devices used in public places and small medical devices and health care devices used at home or carried by individuals as well as over various medical devices used in hospitals or health examination centers has increased.

Since biological signals detected from a living organism vary with the respective organs, the biological signals should be continuously measured at a fixed position in order to accurately sense a change of the living organism by measuring the biological signals. However, when a medical device is installed in a wearable apparatus, the biological signal measuring position may change due to a movement of the living organism. As a result, the reliability of measured biological signal data may decrease.

SUMMARY

One or more exemplary embodiments provide apparatuses for and methods of measuring a biological signal capable of improving a reliability of measured biological signal data by uniformly maintaining a measuring position of a biological signal.

According to an aspect of an exemplary embodiment, there is provided a biological signal measuring apparatus includes a plurality of reference point sensors configured to detect signals detected from at least two reference marks on a surface of a subject; a biological signal measuring position detector configured to generate information about a biological signal measuring position based on the signals detected from the at least two reference marks; and a biological signal measuring sensor configured to measure the biological signal according to the information about the biological signal measuring position.

The biological signal measuring position detector may be further configured to store information about reference signals detected from the at least two reference marks.

The biological signal measuring position detector may be further configured to compare the signals detected from the reference marks with the reference signals to generate the information about the biological signal measuring point.

The biological signal measuring position detector may be further configured to determine whether a degree of similarity between the signals detected from the reference marks and the reference signals is within an allowable range.

The biological signal measuring sensor may be further configured to measure the biological signal only when the biological signal measuring position detector determines that the degree of similarity is within the allowable range.

The biological signal measuring sensor may determine and store the measured biological signal as a valid signal only when the biological signal measuring position detector determines that the degree of similarity is within the allowable range.

Each of the plurality of reference point sensors may include a light source to radiate a light onto the surface of the subject on which the reference marks are attached and a spectrum analyzer to analyze a spectrum of the light reflected from the surface of the subject.

Each of the plurality of reference point sensors may include at least two electrodes that are in contact with the surface of the subject on which the reference marks are attached and an impedance measurer to measure an impedance between the at least two electrodes.

The biological signal measuring sensor may include a light source to radiate a light onto the biological signal measuring position and a spectrum analyzer to analyze a spectrum of the light reflected from the biological signal measuring position.

The biological signal measuring sensor may include at least two electrodes placed at the biological signal measuring position and an impedance measurer to measure an impedance between the at least two electrodes.

The reference marks may include at least one of polydimethylsiloxane (PDMS) and epoxy resin.

The biological signal measuring apparatus may include at least one of a tattoo sticker, an adhesive tape, or an E-skin on which the at least two reference marks are attached.

The biological signal measuring apparatus may include an alarm signal generator to generate an alarm signal if the biological signal measuring position detector determines that the degree of similarity is beyond the allowable range.

According to an aspect of another exemplary embodiment, there is provided a biological signal measuring method includes detecting signals generated from at least two reference marks on a surface of a subject; generating information about a biological signal measuring position based on the detected signals; and measuring a biological signal according to the information about the biological signal measuring position.

The generating the information about the biological signal measuring position may include storing information about reference signals corresponding to the at least two reference marks, and determining whether a degree of similarity between the detected signals and the reference signals is within an allowable range.

The measuring the biological signal may measure the biological signal only when the degree of similarity between the detected signals and the reference signals is within the allowable range.

The measuring the biological signal may include determining and storing the measured biological signal as a valid signal only when the degree of similarity between the detected signals and the reference signals is within the allowable range.

The biological signal measuring method may include generating of an alarm signal when the ratio of the signals detected from the reference marks and the reference signals is not within an allowable range.

The biological signal measuring method may further include displaying the at least two reference marks on a surface of the subject by using at least one from among a tattoo sticker, an adhesive tape, or an E-skin on which the at least two reference marks are attached.

According to an aspect of another exemplary embodiment, there is provided a biological signal measuring apparatus includes a storage configured to store a reference blood vessel image photographed at a reference point on a subject; a blood vessel photographing unit to photograph a blood vessel image of the subject; a biological signal measuring position detector to compare the photographed blood vessel image with the reference blood vessel image and generate information about a biological signal measuring position based on a result of the comparison; and a biological signal measuring sensor to measure a biological signal based on the information about the biological signal measuring position.

The blood vessel photographing unit may include a light source to radiate a light onto a surface of the subject, a measurer to measure a light absorption rate with respect to the subject, and an image generator to generate the photographed blood vessel image based on the light absorption rate.

The biological signal measuring position detector may determine whether a similarity of the blood vessel image photographed by the blood vessel photographing unit and the reference blood vessel image is within an allowable range.

The biological signal measuring apparatus may include an alarm signal generator configured to generate an alarm signal if the biological signal measuring position detector determines that the similarity between the photographed blood vessel image photographed and the reference blood vessel image is beyond the allowable range.

According to an aspect of another exemplary embodiment, there is provided a biological signal measuring method may include storing of a reference blood vessel image photographed at a reference point on a subject; photographing of a blood vessel image of the subject; comparing of the blood vessel image photographed by the blood vessel photographing unit with the reference blood vessel image and outputting information about a biological signal measuring position; and measuring of a biological signal based on the information about the biological signal measuring position.

DETAILED DESCRIPTION

In the following description, when a layer, region, or component is referred to as being “above” or “on” another layer, region, or component, it can be directly or indirectly on the other layer, region, or component.

In the following embodiments, terms such as “first”, “second”, and so forth are used only for distinguishing one component from another component, rather than for restrictive meanings.

An expression used in the singular encompasses the expression of the plural, unless it has a clearly different meaning in the context. Also, throughout the specification, when a portion “includes” an element, another element may be further included, rather than excluding the existence of the other element, unless otherwise described.

Additionally, terms used herein, such as “unit” or “module”, mean entities for processing at least one function or operation. These entities may be implemented by hardware, software, or a combination of hardware and software.

FIG. 1is a view illustrating a biological signal measuring apparatus100according to an exemplary embodiment.FIG. 2is a block diagram of the biological signal measuring apparatus according to the exemplary embodiment ofFIG. 1.

The biological signal measuring apparatus100ofFIG. 1may be placed on a surface of a subject10to measure a biological signal from the subject10. The biological signal may be a signal generated from the surface of the subject10and may include a reflected light signal or an electrical signal returning from the subject10after the light signal or the electrical signal is projected or applied onto the surface of the subject10. Furthermore, the biological signal may include impedance information measured between any two points on the surface of the subject10. The presented examples are not limited and the biological signal may be any signal having biological information of the subject10. The biological information is subject-specific information and may be a signal according to a movement of a specific individual (e.g., heart or muscle) of the subject, such as electrocardiogram (ECG), ballistocardiogram (BCG), photoplethysmograph (PPG), electromyogram, and blood pressure, or may be information about material included in the subject, i.e., blood sugar, cholesterol, or the amount of body fat but is not limited thereto. The biological signal measuring apparatus100ofFIG. 1is a bracelet-type, but is not limited thereto. The biological signal measuring apparatus100according to an exemplary embodiment may be of any type that covers or is placed on the subject10. Moreover, the biological signal measuring apparatus100according to another exemplary embodiment may be of a portable type that temporarily measures the biological signal from the surface of the subject10without covering or being placed on the subject10.

Referring toFIGS. 1 and 2, the biological signal measuring apparatus100according to an exemplary embodiment may include reference point sensors110to detect signals detected from at least two reference marks14attached on the surface of the subject10. Furthermore, the biological signal measuring apparatus100according to an exemplary embodiment may include a biological signal measuring position detector120to output information about a biological signal measuring position based on the signals detected from the at least two reference marks14, and a biological signal measuring sensor130to measure the biological signal according to the information about the biological signal measuring position.

The reference marks14may be attached on the surface of the subject10. Positions of the reference marks14on the subject10may be changed according to a target measuring position12where the biological information is measured. For example, positions of the reference marks14may be differently set in consideration of arrangement relationship between the reference point sensors110and130of the biological information measuring apparatus100and the target measuring position12. Thus, the reference marks14may show a reference so as to match the biological signal measuring position with the target measuring position12. The biological signal measuring position is a position at which the biological signal measuring sensor130measures the biological signal measuring position and, for example, may be a position of the subject10opposed to the biological signal measuring sensor130. At least two reference marks14may be formed. When the reference point sensors110are located to correspond to the reference marks14, the biological signal measuring position may be matched with the target measuring position12.

The reference marks14may be attached on the surface of the subject10by using at least one of a tattoo sticker, an adhesive tape, or an E-skin. The tattoo sticker, the adhesive tape and the E-skin may have preliminary reference marks. The preliminary reference marks, as the reference marks14, may be attached on the surface of the subject10when the tattoo sticker, the adhesive tape, or the E-skin is attached to the subject10and then is separated therefrom. The tattoo sticker, the adhesive tape, or the E-skin having the preliminary reference marks may form pairs with the reference point sensors110. Therefore, the position of the preliminary reference marks on the tattoo sticker, the adhesive tape, or the E-skin and those of the reference point sensors110in the biological signal measuring apparatus100may correspond to each other.

The reference marks14may generate signals different from those generated from the surface of the subject10where the reference marks14are not attached. To achieve this, the reference marks14may independently generate the light signal or the electrical signal as described above. As another example, the reference marks14may have constituents different from that of the surface of the subject10. The reference marks14may include at least one of polydimethylsiloxane (PDMS) and epoxy resin but is not limited thereto. By forming the reference marks14as described above, the signals detected from the reference marks14may be differentiated from that from another portion of the subject10on which the reference marks14are not displayed.

The reference point sensors110may include a plurality of sensing elements so as to detect signals detected from each of the at least two reference marks14. Moreover, arrangement positions of the reference point sensors110may correspond to the display position of the at least two reference marks14. The reference point sensors110may detect the signals detected from the at least two reference marks14. Detecting methods of the signals detected from the reference marks14may vary. For example, the reference marks14may independently generate electrical signals or light signals and the reference point sensors110may detect the generated signals. As another example, when the reference marks14have constituents different from that of the surface of the subject10, the reference point sensors110may measure signals that are the light signals or the electrical signals applied to and returned from the surface of the subject10on which the reference marks14are displayed. The reference point sensors110may distinguish the signals detected from the reference marks14from the signals detected from another portion of the reference marks14on which the reference marks14are not displayed.

FIG. 3is a block diagram of an example of sensors ofFIGS. 1 and 2.

Referring toFIG. 3, the reference point sensors110may include a light source112to radiate light onto a surface of the subject10on which the reference marks14are displayed, and a spectrum analyzer114analyzing a spectrum of the light reflected from the reference marks14. As described above, when the reference marks14have constituents different from that of the surface of the subject10, the light reflected from the reference marks14and the light reflected from the another portion of the subject10on which the reference marks14are not displayed may have different spectrums. The spectrum analyzer114may analyze a spectrum of the light reflected from the subject10on which the reference marks14are displayed. The spectrum analyzer114may analyze an intensity distribution of each wavelength of the reflected lights. Furthermore, the spectrum information of the reflected lights may be provided to the biological signal measuring position detector120.

FIG. 4is a view illustrating another example of the sensors ofFIGS. 1 and 2.

Referring toFIG. 4, the reference point sensors110may include at least two electrodes116aand116bto be in contact with a surface of the subject on which the reference marks are attached. The sensors100may also include an impedance measurer118measuring an impedance between the at least two electrodes116aand116b. The at least two electrodes116aand116bmay correspond to the at least two reference marks14. Therefore, an arrangement position of the electrodes116aand116bin the biological signal measuring apparatus100may also correspond to those of the reference marks14in the subject10.FIG. 4illustrates the electrodes116aand116b, and the impedance measurer118measuring the impedance between the two electrodes116aand116bbut the exemplary embodiment is not limited thereto. For example, the reference point sensors110may include at least three electrodes and the impedance measurer118may measure an impedance between any two electrodes from among the electrodes.

As described above, when the constituent of the subject10is different from those of the reference marks14, a constituent of a path I in which current flows between the electrodes116aand116bmay change according to whether or not the electrodes116aand116bare disposed on the reference marks14. In other words, the impedance between the electrodes116aand116bmay change according to whether or not the electrodes116aand116bare disposed on the reference marks14. The impedance measurer118may input a predetermined current through the electrodes116aand116band measure a voltage between the electrodes116aand116b, and thus may measure the impedance between the electrodes116aand116b. As another example, the impedance measurer118may apply a predetermined voltage between the electrodes116aand116band measure a current flowing between the electrodes116aand116b, and thus also may measure the impedance between the electrodes116aand116b. The impedance information measured by the impedance measurer118may be transmitted to the biological signal measuring position detector120that will be described below.

Referring again toFIG. 2, the biological signal measuring position detector120may receive information measured by the reference point sensors110and output the information about a biological signal measuring position. The information about the biological signal measuring position may include information about whether the biological signal measuring position matches the target measuring position12. In addition, the information about the biological signal measuring position, if the biological signal measuring position is different from the target measuring position12, may include information about whether a distance difference between them is within an allowable range. The allowable range may have a value corresponding to a reliability of the measured biological signal. For example, the allowable range may be set relatively large if the change in the reliability of the measured biological signal according to the position of the biological signal measured near the target measuring position12is relatively small. As another example, the allowable range may be set relatively small if the change in the reliability of the measured biological signal according to the position of the biological signal measured near the target measuring position12is relatively large.

In order to output the information about the biological signal measuring position, the biological signal measuring position detector120may store information about reference signals detected from the at least two reference marks14. The reference signals may be signals detected from the reference marks14measured by the reference point sensors110when positions of the reference point sensors110match those of the reference marks14. The information about the reference signals may be stored in advance in the biological signal measuring position detector120in a manufacturing process of the biological signal measuring apparatus100. For example, a manufacturer of the biological signal measuring apparatus100may match positions of the reference point sensors110with those of the reference marks14and store signals detected from the reference marks14measured by the reference point sensors110as reference signals. As another example, a user may directly match positions of the reference point sensors110with those of the reference marks14and thus store and set signals measured by the reference point sensors110as reference signals.

When a difference between the signals detected from the reference marks14measured by the reference point sensors110and the reference signals is smaller than an allowable error, the biological signal measuring position may correspond to the target measuring position12. That the biological signal measuring position corresponds to the target measuring position12may represent that the distance difference between the biological signal measuring position and the target measuring position12is within the allowable range.

The biological signal measuring position detector120may output the information about the biological signal measuring position by comparing the signals detected from the reference marks14with the reference signals. For example, the biological signal measuring position detector120may determine whether a ratio of the signals detected from the reference marks14and the reference signals is within an allowable error range in order to analyze the difference between the signals detected from the reference marks14and the reference signals. The biological signal measuring apparatus100may determine whether the distance difference between the biological signal measuring position and the target measuring position12is within the allowable error range. The analyzing method for comparing the signals detected from the reference marks14with the reference signals is not limited thereto. For example, the biological signal measuring position detector120may calculate the difference between the signals detected from the reference marks14and the reference signals, and may output information about the biological signal measuring position on the basis of the difference.

According to the type of the reference point sensors110, an output method of the information about the biological signal measuring position of the biological signal measuring position detector120may also change. For example, the reference marks14may independently generate light signals or electrical signals. When positions of the reference point sensors110match those of the reference marks14, the biological signal measuring position detector120may store information about the light signals or the electrical signals measured by the reference point sensors110as information about the reference signals. The reference signals may be stored in advance in the manufacturing process of the biological signal measuring apparatus100as described above, or a user may store a value measured at an initial measuring position as the reference signals. The biological signal measuring position detector120may compare the light signals or the electrical signals measured by the reference point sensors110with the reference signals. Furthermore, the biological signal measuring position detector120may determine whether the ratio of the light signals or the electrical signals measured by the reference point sensors110to the reference signals is within the allowable error range.

As another example, the reference marks14may have constituents different from that of the subject10, and the reference point sensors110may include at least two electrodes116aand116band the impedance measurer118as illustrated inFIG. 4. The biological signal measuring position detector120may store an impedance value measured by the impedance measurer118as information about the reference signals when positions of the electrodes116aand116bof the reference point sensors110match those of the reference marks14. The reference signals may be stored in advance in the manufacturing process of the biological signal measuring apparatus100as described above, or a user may store a value measured at an initial measuring position as the reference signals. The biological signal measuring position detector120may compare an impedance value measured by the impedance measurer118with an impedance value with respect to the reference signals. For example, the biological signal measuring position detector120may determine whether the ratio of the impedance value measured by the impedance measurer118to the impedance value with respect to the reference signals is within an allowable range.

As further another example, the reference marks14may have material different from that of the subject10, and the reference point sensors110may include the light source112and the spectrum analyzer114as illustrated inFIG. 3. In this case, the biological signal measuring position detector120may store a spectrum of the light measured by the reference point sensors110as information about the reference signals when positions of the reference point sensors110match those of the reference marks14. The reference signals may be stored in advance in the manufacturing process of the biological signal measuring apparatus100as described above, or a user may store a value measured at an initial measuring position as the reference signals. Since constituents of the reference marks14is different from that of the surface of the subject10, a spectrum curve of the light measured by the reference point sensors110may change according to whether the positions of the reference point sensors110match those of the reference marks14.

FIG. 5is a graph illustrating an example of a result of an absorption spectrum measured from light reflected from the skin of a human body on which light is radiated.

InFIG. 5, a vertical axis represents a light absorption rate and a horizontal axis represents a wave number of the light. As shown inFIG. 5, spectrum peaks are formed near about 3000 cm−1, 1000 cm−1to 1500 cm−1, and 600 cm−1of the wave number. This is because that moisture included in the skin efficiently absorbs light having a wave number of about 3000 cm−1, protein efficiently absorbs light having a wave number of about 1000 cm−1to 1500 cm−1, and amid II efficiently absorbs light having a wave number of about 600 cm−1.

FIG. 6is a graph illustrating an example of a result of an absorption spectrum measured from light reflected from polydimethylsiloxane (PDMS), which is an example of material which may be included in the reference marks14.

InFIG. 6, a vertical axis represents a light absorption rate and a horizontal axis represents a wave number of the light. As shown inFIG. 6, a plurality of spectrum peaks are formed within the range of about 900 cm−1to 1300 cm−1of the wave number. For example, spectrum peaks may be formed near about 903 cm−1, 1064 cm−1, and 1267 cm−1of the wave number. That is, PDMS may have a high light absorption rate in a wave number region different from skin. Therefore, when the subject10is a human body and the reference marks include PDMS material, a spectrum curve obtained from the spectrum analyzer114may more resemble the spectrum curve ofFIG. 6rather than the spectrum curve ofFIG. 5as the position of the reference point sensors110becomes closer to the reference marks14. In other words, the spectrum peaks ofFIG. 6are gradually higher as the position of the reference point sensors110becomes closer to the reference marks14while the spectrum peaks ofFIG. 5are gradually lowered.

The biological signal measuring position detector120may store a spectrum of the light measured by the spectrum analyzer114as information about the reference signals when positions of the reference point sensors110match those of the reference marks14. The reference signals may be stored in advance in the manufacturing process of the biological signal measuring apparatus100as described above, or a user may store a value measured at an initial measuring position as the reference signals. The biological signal measuring position detector120may compare the spectrum of the light measured by the spectrum analyzer114with a spectrum of the light with respect to the reference signals. For example, the biological signal measuring position detector120may determine whether a ratio of a peak value in the range of a predetermined wavelength shown in a spectrum analyzed by the spectrum analyzer114to a peak value in the range of a predetermined wavelength shown in a spectrum with respect to the reference signals is within an allowable error range.

FIG. 7Ais a view illustrating a case where a biological signal measuring position does not coincide with the target measuring position, andFIG. 7Bis a view illustrating a case where a biological signal measuring position coincides with the target measuring position. An operating method of the biological signal measuring sensor130may change inFIGS. 7A and 7B.

FIG. 7Ashows that a position of the biological signal measuring sensor130is deviated from the target measuring position12as a position of the reference point sensors110becomes deviated from the reference marks14. In the case ofFIG. 7A, the biological signal measuring position detector120may determine that a ratio of signals detected from the reference marks to the reference signals is not within an allowable error range. Therefore, the biological signal measuring sensor130may interrupt biological signal measuring on the basis of a determination result of the biological signal measuring position detector120. This is due to reduction in reliability of the measured data. As another example, in the case ofFIG. 7A, the biological signal measuring sensor130may determine that the measured biological signal data is invalid data and thus not store or separately manage the measured biological signal data.

FIG. 7Bshows an adjusted position of the biological signal measuring apparatus100. information about the biological signal measuring position that is outputted from the biological signal measuring position detector120may be changed when the position of the biological signal measuring apparatus100is adjusted as above. In other words, the biological signal measuring position detector120may determine that the biological signal measuring position corresponds to the target measuring position12when the position of the reference point sensors110is adjusted so as to be matched with the reference marks14. Therefore, the biological signal measuring sensor130may continue the biological signal measuring on the basis of determination of the biological signal measuring position detector120as the reliability of the measured data is maintained.

The biological signal measuring sensor130may measure a biological signal of the subject10in various manners.FIG. 8is a block diagram of a biological signal measuring sensor according to an exemplary embodiment.FIG. 9is a view illustrating the biological signal measuring sensor according to another exemplary embodiment.

Referring toFIG. 8, the biological signal measuring sensor130may include a light source132to radiate light to a biological signal measuring position and a spectrum analyzer134analyzing a spectrum of the light reflected from the biological signal measuring position. In this case, the biological signal measuring sensor130may provide information about a constituent distributed in a surface of the subject10from the spectrum of the light obtained from the spectrum analyzer134.

Referring toFIG. 9, the biological signal measuring sensor130may include at least two electrodes136aand136bformed in the biological signal measuring position and an impedance measurer138measuring an impedance between at least two electrodes136aand136b. In this case, the biological signal measuring sensor130may provide information about a constituent forming the subject10or a blood vessel size of the subject10from the impedance information measured by the impedance measurer138.

FIGS. 1 and 2illustrate that the reference point sensors110and the biological signal measuring sensor130are physically separated from each other, but the configuration is not limited thereto. For example, the reference point sensors110and the biological signal measuring sensor130may be supplied with power from an identical power source. The reference point sensors110and the biological signal measuring sensor130may detect light radiated from the identical power source independently from each other and may respectively use the light for signal measuring.

FIG. 10is a block diagram of a modified example of the biological signal measuring apparatus100ofFIG. 1.

Referring toFIG. 10, the biological signal measuring apparatus100may include an alarm signal generator140to generate an alarm signal when the biological signal measuring position detector120determines that a ratio of signals detected from the reference marks14and the reference signals is not within an allowable error range. The alarm signal generator140may be formed in various manners. For example, the alarm signal generator140may include a display or a bulb visually showing the alarm signal. As another example, the alarm signal generator140may include a speaker that generates the alarm signal as an alarm sound to be heard.

The biological signal measuring apparatus100according to an exemplary embodiment is described above by referring toFIGS. 1 to 10. A biological signal measuring method using the biological signal measuring apparatus100according to another exemplary embodiment will be described below. The embodiments of the biological signal measuring apparatus100described above may be applied to the biological signal measuring method described below.

FIG. 11is a flow chart illustrating a biological signal measuring method according to an exemplary embodiment.

Referring toFIG. 11, the biological signal measuring method according to the exemplary embodiment may include detecting signals detected from at least two reference marks14attached on a surface of the subject10(S1120), outputting information about a biological signal measuring position based on the signals detected from the at least two reference marks14(S1130), and measuring the biological signal according to the information about the biological signal measuring position (S1140).

In addition, the biological signal measuring method may include placing the reference marks on the surface of the subject10(S1110) in order to perform the operation (S1120) of detecting signals detected from the at least two reference marks14. The reference marks may be placed or attached by using at least one of a tattoo sticker, an adhesive tape, or an E-skin on which the at least two reference marks are attached, but is not limited thereto.

The operation (S1120) of detecting signals detected from the marks and the step (S1140) of measuring the biological signal may use the method of radiating the light and analyzing the spectrum, and the method of measuring the impedance between the two electrodes, as described above by referring toFIGS. 3 and 4, but are not limited thereto.

FIG. 12is a flow chart illustrating an example of an operating method of the operation (S1130) of outputting information about a biological signal measuring position and the o (S1140) of measuring the biological signal.

Referring toFIG. 12, the operation (S1130) of outputting information about the biological signal measuring position may include storing information about reference signals corresponding to the at least two reference marks14(S1132), comparing the signals detected from the reference marks14with the reference signals (S1134), and determining whether a ratio of the signals detected from the reference marks14to the reference signals is within an allowable range (S1136). Furthermore, the operation (S1140) of measuring the biological signal may include measuring a biological signal when the ratio of the signals detected from the reference marks14to the reference signals is within the allowable range (S1142), and interrupting the biological signal measuring when the ratio of the signals detected from the reference marks14to the reference signals is beyond the allowable range (S1144).

FIG. 13is a flow chart illustrating another example of the operating method of the operation (S1130) of outputting information about a biological signal measuring position and the operation (S1140) of measuring the biological signal.

Referring toFIG. 13, the operation (S1130) of outputting information about the biological signal measuring position may include storing information about reference signals corresponding to the at least two reference marks14(S1132_, comparing the signals detected from the reference marks14with the reference signals (S1134), and determining whether a ratio of the signals detected from the reference marks14to the reference signals is within an allowable range (S1136). Furthermore, the operation (S1140) of measuring the biological signal may include determining the measured biological signal data as valid data and storing it when the ratio of the signals detected from the reference marks14to the reference signals is within the allowable range (S1146), and determining that the measured biological signal data is invalid data and thus not storing or separately managing the measured biological signal data when the ratio of the signals detected from the reference marks14and the reference signals is beyond the allowable range (S1148).

According to the biological signal measuring method of the exemplary embodiment, the alarm signal may be generated when the biological signal measuring position is deviated from the target measuring position12.FIG. 14is a flow chart illustrating a biological signal measuring method including generating of an alarm signal, according to an exemplary embodiment.

Referring toFIG. 14, the biological signal measuring method may include generating the alarm signal (S1150) when it is determined that the ratio of the signals detected from the reference marks14to the reference signals is outside the allowable range in operation S1136operation. The operation (S1150) of generating the alarm signal may generate the alarm signal visually through a display or a bulb, or may generate audibly through a speaker.

The biological signal measuring apparatus100and the method thereof according to the exemplary embodiments has been described above referring toFIGS. 1 to 10. A biological signal measuring apparatus and a method thereof according to another exemplary embodiment will be described below.

FIG. 15is a block diagram illustrating a biological signal measuring apparatus200according to another exemplary embodiment.

Referring toFIG. 15, the biological signal measuring apparatus200according to the exemplary embodiment may include a storage210to store a reference blood vessel image photographed at a reference point on a subject, and a blood vessel photographing unit220to photograph a blood vessel image of the subject. The reference point (also referred to as “reference area”) may be a point or area of the subject at which the biological signal is measured. Furthermore, the biological signal measuring apparatus200may include a biological signal measuring position detector230to output information about a biological signal measuring position by comparing the blood vessel image photographed at the blood vessel photographing unit220and the reference blood vessel image, and a biological signal measuring sensor240to measure the biological signal based on the information about the biological signal measuring position.

FIG. 16is a view illustrating a blood vessel image shown at and near a reference point22set in a subject20.

The subject20is a human body and the reference area22is an arm of the human body inFIG. 16. However, this is only an example, the subject type and the reference area or point may change as needed. Referring toFIG. 16, blood vessels are distributed in the arm and a hand of the subject20. The blood vessel image may change corresponding to the subject20and the position of the subject20. Therefore, it is possible to obtain not only information about the subject20itself but also information about the area at which the blood vessel image is photographed by photographing the blood vessel image.

The blood vessel photographing unit220may photograph the blood vessel image of the subject20in various manners.FIG. 17is a block diagram of an example of the blood vessel photographing unit220.

Referring toFIG. 17, the blood vessel photographing unit220may include a light source222that may radiate light onto a surface of the subject, a measurer224that may measure a light absorption rate with respect to the subject20, and an image generator226that may generate the blood vessel image based on the infrared absorption rate measured by the measurer224. Since blood has an infrared absorption rate different from that of another tissue of the subject20, the blood vessel image may be generated by measuring the infrared absorption rate in the subject20.

The light source222may radiate lights having wavelengths that may be better or not absorbed by blood than other tissues of the subject20. For example, the light source222may radiate light of a wavelength band of about 850 nm to 980 nm, which has a high blood absorption rate with respect to hemoglobin. As another example, the light source222may radiate light of a wavelength band of about 390 nm to 750 nm, which has a low blood absorption rate with respect to hemoglobin.

The measurer224may sense a signal of a reflected light or a transmitted light from the subject20. The image generator226may generate the blood vessel image from measured data of the measurer224. The image generator226may generate blood vessel coordinate data from absorption rate data measured by the measurer224. The blood vessel coordinate data may include information about depth at which blood vessel is located and thickness of the blood vessel in the subject20.

It can be known whether a biological signal measuring position matches with the reference point22by comparing the blood vessel image photographed at the reference point22to measure a biological signal with the blood vessel image photographed at the biological signal measuring position to measure the biological signal in the subject20. Therefore, the biological signal measuring position detector230may compare a blood vessel image photographed by the blood vessel photographing unit220with the reference blood vessel image stored in the storage210. The biological signal measuring position detector230may determine whether a similarity of the blood vessel image photographed by the blood vessel photographing unit220and the reference blood vessel image is within an allowable range. The similarity may be determined by information about whether the blood vessels shown in the two images are overlapped in a predetermined ratio or more and a distance needs to be shifted in order to overlap the two images.

An operating method of the biological signal measuring sensor240may change according to whether information about the biological signal measuring position outputted from the biological signal measuring position detector230matches with the reference point22. For example, the biological signal measuring sensor240may measure the biological signal when the similarity is within an allowable range, and may interrupt the biological signal measuring when the similarity is outside the allowable range. As another example, the biological signal measuring sensor240may store the measured data as valid data when the similarity is within the allowable range, or may determine the measured biological signal data as invalid data and thus not store or separately manage it when the similarity is beyond the allowable range.

The embodiments described referring toFIGS. 8 and 9of may be applied to the biological signal measuring sensor240. Therefore, the biological signal measuring sensor240may include the light source and the spectrum analyzer. Furthermore, the biological signal measuring sensor240may include at least two electrodes and the impedance measurer to measure an impedance between the at least two electrodes.

The biological signal measuring apparatus200may generate an alarm signal when the biological signal measuring position is deviated from the reference point22.FIG. 18is a block diagram of the biological signal measuring apparatus200according to an exemplary embodiment.

Referring toFIG. 18, biological signal measuring apparatus200may include an alarm signal generator250. The alarm signal generator250may generate an alarm signal if the biological signal measuring position detector230determines that a similarity of the blood vessel image photographed by the blood vessel photographing unit220and the reference blood vessel image is not within an allowable range. The alarm signal generator250may include a display or a bulb to visually generate the alarm signal. As another example, the alarm signal generator250may include a speaker to audibly generate the alarm signal.

The biological signal measuring apparatus200according to an exemplary embodiment is described above by referring toFIGS. 15 to 18. A biological signal measuring method using the biological signal measuring apparatus200according to another exemplary embodiment will be described below. The whole embodiments described above by referring toFIGS. 15 to 18may be applied to the biological signal measuring method described below.

FIG. 19is a flow chart illustrating a biological signal measuring method according to another exemplary embodiment.

Referring toFIG. 19, the biological signal measuring method according to the exemplary embodiment may include storing a reference blood vessel image photographed at the reference point22of the subject20(S1910), photographing a blood vessel image of the subject20(S1920), comparing the blood vessel image photographed at the operation S1920with the reference blood vessel image and outputting information about a biological signal measuring position (S1930), and measuring a biological signal based on the information about the biological signal measuring position (S1940).

The operation (S1920) of photographing the blood vessel image may radiate light onto the subject20, measure a light absorption rate and generate the blood vessel image by using the light absorption rate. However, this is only a sample, the biological signal measuring method is not limited thereto. Furthermore, the operation (S1930) of outputting information about the biological signal measuring position may include analyzing whether a similarity of the blood vessel image photographed and the reference blood vessel image is within an allowable range. In addition, operation S1940may include measuring the biological signal only when the similarity is within the allowable range. As another example, operation S1940may include measuring the measured data as valid data when the similarity is within the allowable range, or may determine the measured biological signal data as invalid data and thus not store or separately manage it when the similarity is beyond the allowable range.

FIG. 20is a flow chart illustrating a modified example of the biological signal measuring method ofFIG. 19.

Referring toFIG. 20, the biological signal measuring method according to the exemplary embodiment may include storing a reference blood vessel image photographed at a reference point22of the subject20(S1910), photographing a blood vessel image of the subject20(S1920), comparing the blood vessel image photographed at operation S1920with the reference blood vessel image and outputting information about the biological signal measuring position (S1930), and generating an alarm signal when the biological signal measuring position is deviated from the reference point22(S1950).

The biological signal measuring apparatuses100and200and the method thereof according to the exemplary embodiments are described above by referring toFIGS. 1 to 20. According to the embodiments, a reliability of the measured biological signal data may be improved by uniformly maintain the biological signal measuring position at which the biological signal measuring apparatuses100and200measure the biological signal.

The biological signal measuring apparatuses100and200and the method thereof according to the exemplary embodiments described above may be applied to various devices such as a mobile or a wearable apparatus to provide a health care function.

As described above, according to the one or more of the above exemplary embodiments, reliability of measured biological signal data may be improved by uniformly maintain a biological signal measuring position.