Apparatus and method for estimating bio-information

1. An apparatus for estimating bio-information, the apparatus comprising:

a sensor part comprising a contact pressure sensor array configured to obtain a contact pressure distribution of a contact pressure on a contact surface contacted by an object during a measurement period, and an image sensor configured to obtain a contact image of the object that contacts the contact surface at each measurement time in the measurement period; and

a processor configured to:

obtain a pulse wave signal of a region of interest based on the contact image, wherein amplitudes of the pulse wave signal of the region of interest at each measurement time are determined by using pixel values of the region of interest corresponding to each measurement time;

obtain a contact pressure of the region of interest based on the contact pressure distribution;

extract a peak-to-peak amplitude of each measurement time, by subtracting an amplitude value of a negative (−) point from an amplitude value of a positive (+) point of a waveform envelope of the pulse wave signal corresponding to each measurement time;

obtain an oscillometric envelope by plotting the extracted peak-to-peak amplitude of the pulse wave signal of the region of interest based on a contact pressure at a same measurement time of the peak-to-peak amplitude;

obtain at least one feature value based on the oscillometric envelope; and

estimate the bio-information by using the at least one feature value.

2. The apparatus of claim 1 , wherein the sensor part further comprises a display panel provided between the contact pressure sensor array and the image sensor.

3. The apparatus of claim 2 , wherein the image sensor is further configured to detect light which is emitted from the display panel and is reflected or scattered from the object.

4. The apparatus of claim 1 , wherein the contact pressure sensor array comprises a light-transmitting material.

5. The apparatus of claim 1 , wherein the processor is further configured to divide the contact image into one or more regions, and select the region of interest based on at least one of a region, of the one or more regions, including a characteristic point in the contact image, and a quality of a pulse wave signal of each of the one or more regions.

6. The apparatus of claim 5 , wherein the characteristic point comprises a fingerprint center point of a finger.

7. The apparatus of claim 5 , wherein the processor is further configured to evaluate the quality of the pulse wave signal of each of the one or more regions based on at least one of a maximum amplitude value of the pulse wave signal of each of the one or more regions, a difference between the maximum amplitude value and a minimum amplitude value of the pulse wave signal of each of the one or more regions, and an average amplitude value of the pulse wave signal of each of the one or more regions.

8. The apparatus of claim 5 , wherein the processor is further configured to obtain at least one of a total sum, a mean value, a median value, a maximum value, and a minimum value of image data measured at each measurement time in each of the one or more regions, and a value calculated by applying a pre-defined function to the image data measured at each measurement time in each of the one or more regions, as an amplitude component of the pulse wave signal of each of the one or more regions.

9. The apparatus of claim 1 , wherein the processor is further configured to divide the contact image into one or more regions, and select the region of interest based on a contact pressure at a position corresponding to each of the one or more regions in the contact pressure distribution.

10. The apparatus of claim 1 , wherein the at least one feature value comprises one or more of a first contact pressure value of a maximum amplitude point, a second contact pressure value located to a left of the first contact pressure value, and a third contact pressure value located to a right of the first contact pressure value, the second contact pressure value and the third contact pressure value having a predetermined ratio to the first contact pressure value of the maximum amplitude point, in the oscillometric envelope.

11. The apparatus of claim 1 , wherein the processor is further configured to determine a contact state between the object and the sensor part based on at least one of the contact pressure distribution, the contact image, and the pulse wave signal of the region of interest.

12. The apparatus of claim 11 , further comprising an output circuitry configured to output information on the contact state.

13. The apparatus of claim 1 , wherein the bio-information comprises one or more of blood pressure, vascular age, arterial stiffness, aortic pressure waveform, vascular compliance, stress index, degree of fatigue, skin elasticity, and skin age.

14. A method of estimating bio-information, the method comprising:

obtaining, by using a contact pressure sensor array, a contact pressure distribution of a contact pressure on a contact surface contacted by an object during a measurement period;

obtaining, by using an image sensor, a contact image of the object that contacts the contact surface at each measurement time in the measurement period;

obtaining a pulse wave signal of a region of interest based on the contact image, wherein amplitudes of the pulse wave signal of the region of interest at each measurement time are determined by using pixel values of the region of interest corresponding to each measurement time;

obtaining a contact pressure of the region of interest based on the contact pressure distribution;

extracting a peak-to-peak amplitude of each measurement time, by subtracting an amplitude value of a negative (−) point from an amplitude value of a positive (+) point of a waveform envelope of the pulse wave signal corresponding to each measurement time;

obtaining an oscillometric envelope by plotting the extracted peak-to-peak amplitude of the pulse wave signal of the region of interest based on a contact pressure at a same measurement time of the peak-to-peak amplitude;

obtaining at least one feature value based on the oscillometric envelope; and

estimating the bio-information by using the at least one feature value.

15. The method of claim 14 , wherein the obtaining the pulse wave signal of the region of interest comprises:

dividing the contact image into one or more regions; and

selecting the region of interest based on at least one of a region, of the one or more regions, including a characteristic point in the contact image, and quality of a pulse wave signal of each of the one or more regions.

16. The method of claim 15 , wherein the selecting comprises evaluating the quality of the pulse wave signal of each of the one or more regions based on at least one of a maximum amplitude value of the pulse wave signal of each of the one or more regions, a difference between the maximum amplitude value and a minimum amplitude value of the pulse wave signal of each of the one or more regions, and an average amplitude value of the pulse wave signal of each of the one or more regions.

17. The method of claim 14 , wherein the obtaining the pulse wave signal of the region of interest comprises:

dividing the contact image into one or more regions; and

selecting the region of interest based on a contact pressure at a position corresponding to each of the one or more regions in the contact pressure distribution.