Patent ID: 8781547

Claim:
A method for using a medical device comprising an optical sensor to measure calibrated oxygen saturation in a body tissue, the method comprising: establishing a standard spectral response of blood for a plurality of oxygen saturations by a control processor coupled with the optical sensor; establishing a standard spectral response of a reference material by a spectrometer; determining a spectral power output of each wavelength emitted by the optical sensor by the spectrometer; obtaining an optical sensor output signal response of each wavelength to the reference material by a detector of the optical sensor; determining a calibration curve for the optical sensor using the measured spectral power output and the standard spectral response of blood by the control processor; determining an optical gain for each wavelength for converting a voltage signal generated by the optical sensor to a remittance measurement by the control processor, the optical gain being determined by: using the standard spectral response of the reference material and the measured spectral power output of the optical sensor to generate a remittance measurement value for the reference material that is expected to be measured by the optical sensor, wherein generating the remittance measurement value for the reference material comprises computing a dot product of the standard spectral response of the reference material and the spectral power output of each wavelength emitted by the optical sensor, and dividing the expected remittance measurement value by an actual voltage signal produced by the optical sensor responsive to the optical sensor detecting remitted light at a corresponding wavelength from the reference material; and storing the calibration curve and the optical gain.