Signal processing apparatus
View Patent ↗The present invention involves method and apparatus for analyzing measured signals that are modeled as containing primary and secondary portions. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, the present invention involves utilizing a transformation which evaluates a plurality of possible signal coefficients in order to find appropriate coefficients. Alternatively, the present invention involves using statistical functions or Fourier transform and windowing techniques to determine the coefficients relating to two measured signals. Use of this invention is described in particular detail with respect to blood oximetry measurements.
1. A method of determining pulse rate comprising:
receiving first and second intensity signals from a light-sensitive detector which detects light of at least first and second wavelengths attenuated by body tissue carrying pulsing blood;
electronically determining using one or more signal processing devices of a patient monitor, at least two values corresponding to pulse rate based upon at least two different methods of processing the physiological signals; and
electronically determining using one or more signal processing devices of a patient monitor, a resulting value for pulse rate from the at least two values corresponding to pulse rate, wherein one of the different methods of processing comprises a self optimizing algorithm.
2. The method of claim 1 , wherein the self optimizing algorithm comprises a least squares algorithm.
3. The method of claim 1 , comprising outputting a measurement of pulse rate indicative of said resulting value of said pulse rate.
4. The method of claim 3 , wherein said outputting comprises outputting to a display device said measurement of said pulse rate.
5. A method of determining pulse rate comprising:
sensing physiological signals resulting from the attenuation of light of at least first and second wavelengths by body tissue carrying pulsing blood;
electronically determining using one or more signal processing devices of a patient monitor, at least two values corresponding to pulse rate based upon at least two alternative methods of processing the sensed physiological signals from at least one of the first and second wavelengths; and
electronically determining using one or more signal processing devices of a patient monitor, a resulting value for pulse rate from the at least two values corresponding to pulse rate, wherein the step of determining comprises selecting at least one of the at least two values based on a determination of confidence in the accuracy of physiological signals.
6. The method of claim 5 , comprising outputting a measurement of pulse rate indicative of said resulting value of said pulse rate.
7. The method of claim 6 , wherein said outputting comprises outputting to a display device said measurement of said pulse rate.
8. A method of determining pulse rate comprising:
sensing physiological signals resulting from the attenuation of light of at least first and second wavelengths by body tissue carrying pulsing blood;
electronically determining using one or more signal processing devices of a patient monitor, at least two values corresponding to pulse rate based upon at least two alternative methods of processing the sensed physiological signals from at least one of the first and second wavelengths; and
electronically determining using one or more signal processing devices of a patient monitor, a resulting value for pulse rate from the at least two values corresponding to pulse rate, wherein determining a resulting value comprises averaging the at least two values and wherein said step of averaging comprises averaging over a time window, wherein said window is increased for potential of said physiological parameter having a lower confidence of accuracy and decreased for potential values of said physiological parameter having a higher confidence of accuracy.
9. The method of claim 8 , comprising outputting a measurement of pulse rate indicative of said resulting value of said pulse rate.
10. The method of claim 9 , wherein said outputting comprises outputting to a display device said measurement of said pulse rate.