Signal processing apparatus

1. A method for use in a system comprising a sensor for acquiring photo-plethysmographic data of a patient and a signal processing system for removing a plurality of motion artifacts from said photo-plethysmographic data and for obtaining a measure of at least one physiological parameter from said photo-plethysmographic data, the method comprising:

acquiring said photo-plethysmographic data;

transforming said photo-plethysmographic data;

locating candidate spectral peaks based on said transformed photo-plethysmographic data;

reconstructing a clean photo-plethysmographic signal based on said locating; and

determining said measure of said at least one physiological parameter from said clean photo-plethysmographic signal.

2. The method of claim 1 , wherein the clean photo-plethysmographic signal is substantially free of effects of the plurality of motion artifacts.

3. The method of claim 1 , wherein the at least one physiological parameter comprises blood oxygen saturation.

4. The method of claim 1 , wherein the at least one physiological parameter comprises pulse rate.

5. The method of claim 1 , further comprising:

calculating ratios from said transformed photo-plethysmographic data, wherein said candidate spectral peaks comprise peaks of said ratios; and

selecting a candidate spectral peak as said measure of said at least one physiological parameter.

6. The method of claim 5 , further comprising selectively attenuating values of said transformed photo-plethysmographic data based on the degree to which each value of said transformed photo-plethysmographic data corresponds to the selected measure of said at least one physiological parameter.

7. The method of claim 6 , further comprising reconstructing said clean photo-plethysmographic signal based on said selectively attenuated values of said transformed photo-plethysmographic data.

8. The method of claim 5 , wherein said candidate spectral peaks comprise ratios that are above a selected threshold.

9. The method of claim 1 , wherein said determining comprises:

separating said photo-plethysmographic data into a plurality of data bins, each of said plurality of data bins comprising a plurality of samples of said photo-plethysmographic data;

estimating the likelihood that each of said plurality of data bins corresponds to one or more possible values of said at least one physiological parameter;

selecting one of said possible values as said measure of said at least one physiological parameter based on said estimation.

10. The method of claim 1 , further comprising averaging a time series of values selected as said measure of said at least one physiological parameter to a greater extent based on a determination of the presence of an increased amount of motion artifact in said photo-plethysmographic data, and to a lesser extent based on a determination of the presence of a decreased amount of motion artifact in said photo-plethysmographic data.

11. The method of claim 1 , further comprising:

generating properties of an estimated motion artifact noise signal based on said determined measure of said at least one physiological parameter; and

reconstructing said clean photo-plethysmographic signal by removing portions of said photo-plethysmographic data having properties that correspond to said properties of said estimated motion artifact noise signal.

12. A pulse oximetry system for the determination of a physiological parameter capable of removing motion artifacts from physiological signals, the pulse oximetry system comprising a hardware subsystem and a software subsystem,

wherein said hardware subsystem comprises:

an optical sensor unit for providing said pulse oximetry system with a patient's photo-plethysmographic data, wherein said sensor comprises a light emitting diode for emitting light, a photo-detector for detecting said light, wherein said detected light contains information on the photo-plethysmographic data,

a processor for processing the photo-plethysmographic data, and

a memory unit, wherein said memory unit is operably coupled to said processor, and

wherein the software subsystem is configured to perform a method comprising the steps of:

acquiring said photo-plethysmographic data from the sensor;

conditioning said photo-plethysmographic data for signal processing;

transforming the conditioned data into a frequency domain;

locating candidate spectral peaks based on said transformed conditioned data;

reconstructing a clean photo-plethysmographic signal based on said locating; and

determining said physiological parameter from said clean photo-plethysmographic signal.

13. The pulse oximetry system of claim 12 , wherein the clean photo-plethysmographic signal is substantially free of effects of motion artifacts.

14. The pulse oximetry system of claim 12 , wherein the physiological parameter comprises blood oxygen saturation.

15. The pulse oximetry system of claim 12 , wherein the physiological parameter comprises pulse rate.