Apparatus and method for estimating bio-information
An apparatus for estimating bio-information includes: a sensor part configured to obtain contact pressure of a contact surface contacted by an object, and configured to obtain a contact image of the object that contacts the contact surface; and a processor configured to obtain a pulse wave signal of a region of interest based on the contact image, and configured to estimate bio-information based on the obtained pulse wave signal and the contact pressure.
1. An apparatus for estimating bio-information, the apparatus comprising:
a sensor part comprising an image sensor configured to obtain a contact image of an object that contacts a contact surface at each measurement time in a measurement period, and a force sensor configured to detect a contact force applied by the object that contacts the contact surface during the measurement period; and
a processor configured to:
obtain a pulse wave signal of a region of interest based on the contact image, wherein an amplitude component of the pulse wave signal of the region of interest at a given measurement time is determined by using pixel values of the region of interest corresponding to the given measurement time;
obtain a contact area of the object based on pixel values of at least a portion of region in the contact image;
obtain a contact pressure based on the contact force and the contact area;
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; and
obtain at least one feature value based on the oscillometric envelope, and estimate the bio-information based on the at least one feature value.
2. The apparatus of claim 1 , wherein the sensor part further comprises a display panel which is disposed on the image sensor and is contacted by the object.
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 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.
5. A method of estimating bio-information, the method comprising:
detecting a contact force applied by an object that contacts a contact surface during a measurement period;
obtaining 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 an amplitude component of the pulse wave signal of the region of interest at a given measurement time is determined by using pixel values of the region of interest corresponding to the given measurement time;
obtaining a contact area of the object based on pixel values of at least a portion of region in the contact image;
obtaining a contact pressure based on the contact force and the contact area;
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; and
obtaining at least one feature value based on the oscillometric envelope, and estimating the bio-information based on the at least one feature value.
6. The method of claim 5 , 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 a quality of a pulse wave signal of each of the one or more regions.