Method of calibrating optical sensor, optical sensor, and apparatus for estimating bio-information
A method of calibrating an optical sensor may include acquiring a first characteristic for an external light source through a detector of an optical sensor while an internal light source of the optical sensor is turned off; driving the internal light source; acquiring a second characteristic for the internal light source and the external light source through the detector, based on driving the internal light source; and acquiring a reference characteristic of the internal light source, for calculation of an absorbance of an object, based on the first characteristic and the second characteristic.
1. A method of calibrating an optical sensor, the method comprising:
acquiring a first characteristic for an external light source through a detector of the optical sensor while an internal light source of the optical sensor is turned off;
driving the internal light source;
acquiring a second characteristic for the internal light source and the external light source through the detector, based on driving the internal light source;
acquiring a reference characteristic of the internal light source, for calculation of an absorbance of an object, based on the first characteristic and the second characteristic;
comparing the reference characteristic and an initial characteristic; and
determining whether to perform re-measurement, based on comparing the reference characteristic and the initial characteristic,
wherein the acquiring the reference characteristic comprises acquiring the reference characteristic by subtracting the first characteristic from the second characteristic.
2. The method of claim 1 , wherein the reference characteristic includes at least one of an intensity and a spectral characteristic of light that is emitted from the internal light source and is reflected on an inner reflective surface of the optical sensor.
3. The method of claim 1 , wherein the driving the internal light source comprises modulating at least one of an amplitude and a phase of the internal light source, and
wherein the acquiring the reference characteristic comprises acquiring the reference characteristic using a lock-in detection technique.
4. The method of claim 1 , further comprising:
providing guidance to perform the re-measurement, based on determining that the re-measurement is to be performed.
5. The method of claim 1 , further comprising:
performing an initial calibration; and
acquiring the initial characteristic, based on performing the initial calibration.
6. The method of claim 5 , wherein the performing the initial calibration comprises driving the internal light source in a shielded environment, and
wherein the acquiring the initial characteristic comprises acquiring the initial characteristic by detecting light, reflected by an inner reflective surface of the optical sensor, through the detector.
7. The method of claim 6 , wherein the performing the initial calibration comprises acquiring a third characteristic by detecting light, reflected by an outer reflective surface, through the detector in the shielded environment, and acquiring a spectral transmission constant for calculation of the absorbance of the object based on the initial characteristic and the third characteristic.
8. The method of claim 7 , wherein the acquiring the spectral transmission constant comprises normalizing the third characteristic and the initial characteristic, and acquiring a ratio of normalized values as the spectral transmission constant.