Enhancement of physiological signals using fractal analysis
First Claim
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 light of first and second wavelengths, respectively;
a light detector positioned to detect first and second light signals after interacting with the subject and to generate signals indicative of an intensity of said first and second detected light signals, said first detected 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 detected signal having a first portion arising from light transmitted from said second source and a second portion arising from a second interference source;
a storage location containing a mathematical relationship of said first and second portions of said first and second detected signals and a first ratio of said first portion of said first detected signal to said first portion of said second detected signal;
an analyzer coupled to said storage location to determine a plurality of complexity values for said mathematical relationship over a predetermined range of said first ratio; and
a calculator to determine a selected value for said first ratio based on said complexity values.
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Accused Products
Abstract
A technique for the derivation of a pulse oximetry signal using fractal dimension analysis of detected light signals. First and second light sources transmit light through the patient'"'"'s finger or reflect light off the blood vessels in the patient'"'"'s finger. A light detector detects light from each of the light sources and generates a measured intensity signal. The measured intensity signal includes the true intensity of light transmitted from each of the light sources as well as noise introduced during the measurement process. A data sample from each of the light sources is digitized and a set of equations developed as a function of a ratio value indicative of oxygen saturation in the patient. The fractal dimension is determined for the set of signal functions over the normal physiological range for the ratio value. Maximum and/or minimum fractal dimension values are calculated to determine the desired ratio values which are possible indicatives of the ratio of true physiological signals or noise signals. The ratio values are subsequently processed to determine the oxygen saturation within the patient.
337 Citations
30 Claims
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1. A system for the enhancement of physiological signals for the measurement of blood oxygen in a subject, the system comprising:
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first and second light sources to direct light toward the subject, said first and second light sources producing light of first and second wavelengths, respectively; a light detector positioned to detect first and second light signals after interacting with the subject and to generate signals indicative of an intensity of said first and second detected light signals, said first detected 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 detected signal having a first portion arising from light transmitted from said second source and a second portion arising from a second interference source; a storage location containing a mathematical relationship of said first and second portions of said first and second detected signals and a first ratio of said first portion of said first detected signal to said first portion of said second detected signal; an analyzer coupled to said storage location to determine a plurality of complexity values for said mathematical relationship over a predetermined range of said first ratio; and a calculator to determine a selected value for said first ratio based on said complexity values. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system for the enhancement of physiological signals representative of a physiological phenomenon in a subject, the system comprising:
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a sensor positioned in proximity with the subject to detect physiological signals and to generate signals indicative of said detected physiological signals, said detected signals having a first portion arising from the physiological phenomenon and a second portion arising frown an interference source; an analyzer to analyze and determine a complexity value for said generated signals, said complexity value being indicative of a complexity of said generated signals; and a processor, responsive to said complexity value, to generate a processed signal. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method for the enhancement of physiological signals for the measurement of blood oxygen in a subject, the method comprising the steps of:
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producing light of first and second wavelengths; directing light of said first and second wavelengths toward the subject; detecting first and second light signals after interacting with the subject and generating signals indicative of an intensity of said first and second detected light signals, said first detected signal having a first portion arising from light transmitted with said first wavelength and a second portion arising from a first interference source, said second detected signal having a first portion arising from light transmitted with said second wavelength and a second portion arising from a second interference source; analyzing said first and second detected signals using a mathematical relationship of said first and second portions of said first and second detected signals and a first ratio of said first portion of said first detected signal to said first portion of said second detected signal to determine a plurality of complexity values for said mathematical relationship over a predetermined range of said first ratio; and determining a selected value for said first ratio based on said complexity values. - View Dependent Claims (23, 24, 25)
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26. A method for the enhancement of physiological measurements in a subject, the method comprising the steps of:
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using a plurality of light sources, each producing light of a different predetermined wavelength; directing light of said predetermined wavelengths toward the subject; detecting a plurality of light signals after interacting with the subject and generating signals indicative of an intensity of said plurality of detected light signals, each of said detected signals having a first portion arising from light transmitted with one of said predetermined wavelength and a second portion arising from an interference source; analyzing said plurality of detected signals using a mathematical relationship of said first and second portions of said plurality of detected signals and a first ratio of said first portion of a first of said plurality of detected signals to said first portion of a second of said plurality of detected signals to determine a plurality of complexity values for said mathematical relationship over a predetermined range of said first ratio; and determining a selected value for said first ratio based on said complexity values. - View Dependent Claims (27, 28)
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29. A method for the enhancement of physiological signals representative of a physiological phenomenon in a subject, the method comprising the steps of:
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positioning a sensor in proximity with the subject to detect physiological signals and to generate signals indicative of said detected physiological signals, said detected signals having a first portion arising from the physiological phenomenon and a second portion arising from an interference source; analyzing said generated signals to determine a complexity value for said generated signals, said complexity value being indicative of a complexity of said generated signals; and processing said generated signals using said complexity value to generate processed signals. - View Dependent Claims (30)
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Specification