Signal Procesing Systems and Methods Using Basis Functions and Wavelet Transforms

Abstract

According to embodiments, systems and methods are provided that use continuous wavelet transforms and basis functions to provide an optimized system for the determination of physiological information. In an embodiment, the basis functions may be used to refine an area of interest in the signal in frequency or in time, and the continuous wavelet transform may be used to identify a maxima ridge in the scalogram at scales with characteristic frequencies proximal to the frequency or frequencies of interest. In another embodiment, a wavelet transform may be used to identify regions of a signal with the morphology of interest while basis functions may be used to focus on these regions to determine or filter information of interest. In yet another embodiment, basis functions and continuous wavelet transforms may be used concurrently and their results combined to form optimized information or a confidence metric for determined physiological information.

1 . A method for determining physiological information comprising:
 receiving, using a processor, a signal;   generating, using the processor, first information about the signal using a wavelet transform of the signal for a plurality of scales;   generating, using the processor, second information about the signal using a plurality of basis functions; and   combining, using the processor, the first information and the second information to determine the physiological information.   
     
     
         2 . The method of  claim 1 , further comprising determining a confidence metric based on the first information and the second information, wherein combining the first information and second information comprises combining the first information and second information based on the confidence metric. 
     
     
         3 . The method of  claim 1 , wherein combining the first information and the second information comprises averaging the first information and the second information. 
     
     
         4 . The method of  claim 3 , wherein averaging the first information and the second information comprising calculating a weighted average of the first information and the second information. 
     
     
         5 . The method of  claim 1 , further comprising determining optimized physiological information. 
     
     
         6 . The method of  claim 1 , wherein generating the second information about the signal using the plurality of basis functions comprises:
 generating, using the processor, a basis function subset based at least in part on an expected range of frequencies of a pulse rate signal; and   generating, using the processor, cancellation components based at least in part on the basis function subset.   
     
     
         7 . The method of  claim 1 , wherein generating the first information about the signal using a wavelet transform of the signal for a plurality of scales comprises:
 generating a scalogram based at least in part on the wavelet transform; and   identifying a maxima ridge in the scalogram.   
     
     
         8 . A system for determining physiological information comprising:
 a processor configured to:
 receive a signal; 
 generate first information about the signal using a wavelet transform of the signal for a plurality of scales; 
 generate second information about the signal using a plurality of basis functions; and 
 combine the first information and the second information to determine the physiological information. 
   
     
     
         9 . The system of  claim 8 , wherein the processor is further configured to determine a confidence metric based on the first information and the second information, wherein the processor is configured to combine the first information and second information based on the confidence metric. 
     
     
         10 . The system of  claim 8 , wherein the processor is configured to combine the first information and the second information by averaging the first information and the second information. 
     
     
         11 . The system of  claim 8 , wherein the processor is configured to combine the first information and the second information by calculating a weighted average of the first information and the second information. 
     
     
         12 . The system of  claim 8 , wherein the processor is further configured to determine optimized physiological information. 
     
     
         13 . The system of  claim 8 , wherein the processor is further configured to:
 generate a basis function subset based at least in part on an expected range of frequencies of a pulse rate signal; and   generate cancellation components based at least in part on the basis function subset.   
     
     
         14 . The method of  claim 8 , wherein the processor is further configured to:
 generate a scalogram based at least in part on the wavelet transform; and   identify a maxima ridge in the scalogram.   
     
     
         15 . A non-transitory computer-readable medium for use in determining physiological information, the computer-readable medium having computer program instructions recorded thereon for:
 receiving a signal;   generating first information about the signal using a wavelet transform of the signal for a plurality of scales;   generating second information about the signal using a plurality of basis functions; and   combining the first information and the second information to determine the physiological information.   
     
     
         16 . The non-transitory computer-readable medium of  claim 15 , having further computer program instructions recorded thereon for determining a confidence metric based on the first information and the second information, wherein combining the first information and second information comprises combining the first information and second information based on the confidence metric. 
     
     
         17 . The non-transitory computer-readable medium of  claim 15 , wherein combining the first information and the second information comprises averaging the first information and the second information. 
     
     
         18 . The non-transitory computer-readable medium of  claim 15 , having further computer program instructions recorded thereon for determining optimized physiological information. 
     
     
         19 . The non-transitory computer-readable medium of  claim 15 , wherein generating the second information about the signal using the plurality of basis functions comprises:
 generating, using the processor, a basis function subset based at least in part on an expected range of frequencies of a pulse rate signal; and   generating, using the processor, cancellation components based at least in part on the basis function subset.   
     
     
         20 . The non-transitory computer-readable medium of  claim 15 , wherein generating the first information about the signal using a wavelet transform of the signal for a plurality of scales comprises:
 generating a scalogram based at least in part on the wavelet transform; and   identifying a maxima ridge in the scalogram.