Bio-information estimating apparatus and bio-information estimating method

1. A bio-information estimating apparatus comprising:

an image sensor configured to capture an image of an object that approaches a sensor part;

a display configured to, based on the captured image of the object, display a relative position of the object with respect to a position of the sensor part;

the sensor part configured to, based on the object contacting the position of the sensor part, measure a pulse wave signal from the object, a contact force that is applied by the object to the sensor part, and a contact area of the object that contacts the sensor part; and

a processor configured to:

obtain at least one first feature value, based on a first change in the contact area with respect to a second change in the contact force during a measurement time period, the measurement time period comprising a plurality of measurement time points for measuring the contact area and the contact force;

obtain at least one second feature value, based on the pulse wave signal; and

estimate bio-information, based on the at least one first feature value and the at least one second feature value; and

an output hardware interface configured to output the estimated bio-information,

wherein the processor is further configured to:

create a contact area change graph representing the first change in the contact area with respect to the second change in the contact force, by plotting the contact area with respect to the contact force at each of the plurality of measurement time points in the measurement time period;

perform fitting on the contact area change graph and perform differentiation on the contact area change graph on which the fitting is performed; and

obtain the at least one first feature value, based on the contact area change graph on which the differentiation is performed.

2. The bio-information estimating apparatus of claim 1 , wherein the sensor part comprises:

a pulse wave sensor comprising a light source configured to emit first light onto the object, and a detector configured to detect second light that is reflected from the object; and

a contact pressure sensor comprising a force sensor configured to measure the contact force, and an area sensor configured to measure the contact area.

3. The bio-information estimating apparatus of claim 1 , wherein the processor is further configured to obtain predetermined unit sections of the contact area change graph by dividing an axis of the contact force in the contact area change graph, on which the differentiation is performed, by a preset interval, and

wherein the at least one first feature value comprises any one or any combination of a maximum slope, a minimum slope, and an average slope of each of the predetermined unit sections of the contact area change graph.

4. The bio-information estimating apparatus of claim 1 , wherein the processor is further configured to obtain a contact pressure between the object and the sensor part, based on the contact force and the contact area, and obtain the at least one second feature value, based on the contact pressure and the pulse wave signal.

5. The bio-information estimating apparatus of claim 4 , wherein the processor is further configured to obtain an oscillometric envelope representing the contact pressure versus the pulse wave signal at each of the plurality of measurement time points, and obtain the at least one second feature value, based on the oscillometric envelope.

6. The bio-information estimating apparatus of claim 5 , wherein the at least one second feature value comprises any one or any combination of a maximum amplitude value of the oscillometric envelope, a first contact pressure value corresponding to the maximum amplitude value, a plurality of contact pressure values that are, in a graphical representation of the oscillometric envelope, located to a left and a right of the first contact pressure value and have a predetermined ratio to the first contact pressure value, and a plurality of amplitude values of the oscillometric envelope that corresponds to the plurality of contact pressure values.

7. The bio-information estimating apparatus of claim 4 , wherein the sensor part is further configured to measure a plurality of pulse wave signals from the object, and

wherein the processor is further configured to:

obtain a plurality of oscillometric envelopes, based on the plurality of pulse wave signals and the contact pressure;

obtain a plurality of feature values, based on the plurality of oscillometric envelopes; and

obtain the at least one second feature value by combining the plurality of feature values.

8. The bio-information estimating apparatus of claim 1 , wherein the output hardware interface is further configured to receive a request for estimating the bio-information, and output guide information of a contact pressure between the object and the sensor part based on the request.

9. The bio-information estimating apparatus of claim 8 , wherein the guide information is for inducing a user to gradually increase the contact pressure that is applied by the object to the sensor part, or to gradually decrease the contact pressure when the user touches the sensor part with a pressure intensity greater than or equal to a predetermined threshold.

10. The bio-information estimating apparatus of claim 1 , wherein the processor is further configured to obtain a contact pressure between the object and the sensor part, based on the contact force and the contact area, and determine a contact state between the object and the sensor part, based on the contact pressure.

11. The bio-information estimating apparatus of claim 10 , wherein the processor is further configured to determine whether the contact state is normal, and

wherein the output hardware interface is further configured to, based on the contact state being determined to be not normal, output guide information for inducing a user to change the contact pressure.

12. The bio-information estimating apparatus of claim 1 , wherein the bio-information comprises any one or any combination of a blood pressure, a vascular age, an arterial stiffness, an aortic pressure waveform, a vascular compliance, a stress index, and a degree of fatigue.

13. A bio-information estimating method being performed by a bio-information estimating apparatus, the method comprising:

capturing, by using an image sensor, an image of an object that approaches a sensor part;

based on the captured image of the object, displaying, on a display of the bio-information estimating apparatus, a relative position of the object with respect to a position of the sensor part;

based on the object contacting the position of the sensor part, measuring a pulse wave signal from the object, a contact force that is applied by the object to the sensor part of the bio-information estimating apparatus, and a contact area of the object that contacts the sensor part;

obtaining a at least one first feature value, based on a first change in the contact area with respect to a second change in the contact force during a measurement time period, the measurement time period comprising a plurality of measurement time points for measuring the contact area and the contact force;

obtaining at least one second feature value, based on the pulse wave signal;

estimating bio-information, based on the at least one first feature value and the at least one second feature value; and

outputting, via an output hardware interface, the estimated bio-information,

wherein the obtaining of the at least one first feature value comprises:

creating a contact area change graph representing the first change in the contact area with respect to the second change in the contact force, by plotting the contact area with respect to the contact force at each of the plurality of measurement time points in the measurement time period;

performing fitting on the contact area change graph, and performing differentiation on the contact area change graph on which the fitting is performed; and

obtaining the at least one first feature value, based on the contact area change graph on which the differentiation is performed.

14. The bio-information estimating method of claim 13 , further comprising obtaining predetermined unit sections of the contact area change graph by dividing an axis of the contact force in the contact area change graph, on which the differentiation is performed, by a preset interval,

wherein the at least one first feature value comprises any one or any combination of a maximum slope, a minimum slope, and an average slope of each of the predetermined unit sections of the contact area change graph.

15. The bio-information estimating method of claim 13 , wherein the obtaining of the at least one second feature value comprises:

obtaining a contact pressure between the object and the sensor part, based on the contact force and the contact area; and

obtaining the at least one second feature value, based on the contact pressure and the pulse wave signal.

16. The bio-information estimating method of claim 15 , further comprising obtaining an oscillometric envelope representing the contact pressure versus the pulse wave signal at each of the plurality of measurement time points,

wherein the obtaining of the at least one second feature value further comprises obtaining the at least one second feature value, based on the oscillometric envelope.

17. The bio-information estimating method of claim 16 , wherein the at least one second feature value comprises any one or any combination of a maximum amplitude value of the oscillometric envelope, a first contact pressure value corresponding to the maximum amplitude value, a plurality of contact pressure values that are, in a graphical representation of the oscillometric envelope, located to a left and a right of the first contact pressure value and have a predetermined ratio to the first contact pressure value, and a plurality of amplitude values of the oscillometric envelope that corresponds to the plurality of contact pressure values.