Patent ID: 7376453
Filing Date: 2008-05-20
Classification: A61B,G06K

Abstract:
1. A system for the enhancement of physiological signals for the measurement of blood oxygen in a subject, the system comprising: first and second light sources to direct light toward the subject, said first and second light sources producing first and second light signals of first and second wavelengths, respectively; a light detector positioned to detect said first and second light signals after interaction with the subject and to generate first and second signals indicative of an intensity of said first and second detected light signals, respectively, said first generated signal having a first portion arising from light transmitted from said first source and a second portion arising from a first interference source; said second generated signal having a first portion arising from light transmitted from said second source and a second portion arising from a second interference source; an adaptive signal processor having a signal input coupled to said light detector to receive said first generated signal, an adaptive filter having an input to receive a reference signal, and an output, and an error output to generate an error signal, wherein said error output is coupled to said adaptive filter to adjust said adaptive filter so that a function of said error signal has a minimum; wherein said first and second portions of said first and second generated signals and a first ratio constant have a defined mathematical relationship; a reference signal generator to generate said reference signal based on a possible value of said first ratio constant; and a peak detector to receive an output signal from said adaptive signal processor and determine a calculated value for said first ratio constant corresponding to a first peak value of said output signal over a predetermined range of possible ratios, said reference signal generator generating said first portion of said first detected signal and said first portion of said second detected signal based on said mathematical relationship and said calculated value of said first ratio constant.