Apparatus and method for obtaining bioinformation

1. An apparatus for obtaining bio-information, comprising:

a pulse wave sensor comprising a light source and a detector, the light source configured to emit multi-wavelength light to an object of a user, the detector configured to detect the multi-wavelength light reflected from the object;

a processor configured to obtain a change in volume of a blood vessel based on a difference between a value, obtained by multiplying a quantity of detected light of a first wavelength of the multi-wavelength light by a ratio of an absorbance coefficient of the first wavelength and an absorbance coefficient of a second wavelength of the multi-wavelength light, and a quantity of detected light of the second wavelength, and obtain the bio-information based on the change in volume of the blood vessel, and

an outputter configured to, under a control of the processor, output the obtained bio-information to the user,

wherein upon receiving a request for measuring the bio-information, the outputter is configured to output a visual indication to the user about a magnitude of a force to be applied to the pulse wave sensor by the object, and indicate to the user a magnitude of the force being applied to the pulse wave sensor by the object while the pulse wave sensor is measuring a pulse wave signal.

2. The apparatus of claim 1 , wherein the processor is further configured to differentiate, with respect to time, the difference between the value, obtained by multiplying the quantity of detected light of the first wavelength by the ratio of the absorbance coefficient of the first wavelength and the absorbance coefficient of the second wavelength, and the quantity of detected light of the second wavelength, and obtain the change in volume of the blood vessel based on a differential value.

3. The apparatus of claim 2 , wherein the processor is further configured to generate a graph of the differential value against time and monitor a time interval during which the volume of the blood vessel is changed according to a change in transmural pressure.

4. The apparatus of claim 2 , wherein the processor is further configured to detect one or more peaks based on the differential value and obtain the bio-information using the detected one or more peaks.

5. The apparatus of claim 4 , wherein the processor is further configured to detect, as a peak, a point at which the differential value is greater than a first threshold and a sharpness is greater than a second threshold.

6. The apparatus of claim 5 , wherein the processor is further configured to determine, as a sharpness at a first point, determine a cosine value of an angle, formed between a second point and a third point, the second point and the third point being on a left and a right of the first point.

7. The apparatus of claim 4 , wherein the processor is further configured to extract one or more features based on the detected one or more peaks and force information about the force being applied to the pulse wave sensor by the object.

8. The apparatus of claim 7 , further comprising a force sensor configured to acquire the force information about the force being applied to the pulse wave sensor by the object.

9. The apparatus of claim 7 , wherein the processor is further configured to, from among the one or more peaks, extract, as a first feature, a force value or the differential value at a point corresponding to a smallest force, extract, as a second feature, a force value or the differential value at a point at which the differential value is largest, and extract, as a third feature, a force value or the differential value at a point corresponding to a greatest force.

10. The apparatus of claim 7 , wherein the processor is further configured to obtain the bio-information based on the extracted one or more features.

11. The apparatus of claim 1 , wherein the bio-information comprises information about one or more of blood pressure, vascular age, a degree of arteriosclerosis, aortic pressure waveform, vascular compliance, stress index, and a degree of fatigue.

12. A method of obtaining bio-information, comprising:

emitting multi-wavelength light to an object of a user;

detecting the multi-wavelength light reflected from the object;

obtaining a change in volume of a blood vessel based on a difference between a value, obtained by multiplying a quantity of detected light of a first wavelength of the multi-wavelength light by a ratio of an absorbance coefficient of the first wavelength and an absorbance coefficient of a second wavelength of the multi-wavelength light, and a quantity of detected light of the second wavelength; and

obtaining the bio-information based on the change in volume of the blood vessel and outputting the bio-information to the user,

wherein the method further comprises:

upon receiving a request for measuring the bio-information, outputting a visual indication to the user about a magnitude of a force to be applied to a pulse wave sensor by the object, and indicating to the user a magnitude of the force being applied to the pulse wave sensor by the object while the pulse wave sensor is measuring a pulse wave signal.

13. The method of claim 12 , wherein the obtaining the change in volume of the blood vessel comprises differentiating, with respect to time, the difference between the value obtained by multiplying the quantity of detected light of the first wavelength by the ratio of the absorbance coefficient of the first wavelength and the absorbance coefficient of the second wavelength and obtaining the change in volume of the blood vessel based on a differential value.

14. The method of claim 13 , wherein the obtaining the bio-information comprises detecting one or more peaks based on the differential value.

15. The method of claim 14 , wherein the obtaining the bio-information further comprises extracting one or more features based on the detected one or more peaks and force information about the force being applied to the pulse wave sensor by the object.

16. The method of claim 15 , wherein the obtaining the bio-information comprises obtain the bio-information based on the extracted one or more features.