Systems And Methods For Adaptively Filtering Signals

Abstract

According to embodiments, systems and method are provided for adaptively filtering signals. A combination of filtering techniques is described in which non-wavelet based filtering techniques are used with wavelet-based filtering techniques to filter an input signal. One or more physiological parameters may then be determined from the filtered output signal.

1 . A method for filtering a signal, the method comprising:
 receiving an input signal;   filtering the received input signal using a first adaptive filtering technique to produce a first filtered signal; and   filtering the first filtered signal using a wavelet filtering technique to produce an output filtered signal.   
     
     
         2 . The method of  claim 1 , wherein receiving an input signal comprises receiving at least one photoplethysmograph (PPG) signal. 
     
     
         3 . The method of  claim 1 , wherein filtering the received input signal using a first adaptive filtering technique comprises generating a reference signal from the received input signal. 
     
     
         4 . The method of  claim 3 , wherein filtering the received input signal using a first adaptive filtering technique additionally comprises filtering the received input signal using an adaptive correlation canceller and the generated reference signal. 
     
     
         5 . The method of  claim 1 , wherein filtering the first filtered signal using a wavelet filtering technique comprises transforming the first filtered signal using a continuous wavelet transform. 
     
     
         6 . The method of  claim 5 , wherein filtering the first filtered signal using a wavelet filtering technique comprises generating a scalogram of the continuous wavelet transform of the first filtered signal. 
     
     
         7 . The method of  claim 6  further comprising identifying at least one artifact in the scalogram. 
     
     
         8 . The method of  claim 1 , wherein filtering the first filtered signal using a wavelet filtering technique comprises generating at least two scalograms from the first filtered signal, wherein at least one of the at least two scalograms is a residual scalogram. 
     
     
         9 . The method of  claim 1  further comprising determining at least one physiological parameter from the output filtered signal. 
     
     
         10 . A method for filtering a signal, the method comprising:
 receiving an input signal;   filtering the received input signal using a wavelet filtering technique to produce a first filtered signal; and   filtering the first filtered signal using an adaptive filtering technique to produce an output filtered signal.   
     
     
         11 . A system for filtering a signal, the system comprising:
 a sensor capable of generating an input signal; and   a processor capable of:
 filtering the input signal using a first adaptive filtering technique to produce a first filtered signal; and 
 filtering the first filtered signal using a wavelet filtering technique to produce an output filtered signal. 
   
     
     
         12 . The system of  claim 11 , wherein the sensor is capable of generating at least one photoplethysmograph (PPG) signal. 
     
     
         13 . The system of  claim 11 , wherein the processor is capable of generating a reference signal from the input signal. 
     
     
         14 . The system of  claim 13 , wherein the processor is capable of filtering the input signal using an adaptive correlation canceller and the generated reference signal. 
     
     
         15 . The system of  claim 11 , wherein the processor is capable of transforming the first filtered signal using a continuous wavelet transform. 
     
     
         16 . The system of  claim 15 , wherein the processor is capable of generating a scalogram of the continuous wavelet transform of the first filtered signal. 
     
     
         17 . The system of  claim 16  wherein the processor is capable of identifying at least one artifact in the scalogram. 
     
     
         18 . The system of  claim 11 , wherein the processor is capable of generating at least two scalograms from the first filtered signal, wherein at least one of the at least two scalograms is a residual scalogram. 
     
     
         19 . The system of  claim 11  wherein the processor is capable of determining at least one physiological parameter from the output filtered signal. 
     
     
         20 . A computer-readable medium for use in detecting an artifact in a signal, the computer-readable medium having computer program instructions recorded thereon for:
 receiving an input signal;   filtering the received input signal using a first adaptive filtering technique to produce a first filtered signal; and   filtering the first filtered signal using a wavelet filtering technique to produce an output filtered signal.