Adaptive filtering of physiological signals using a modeled synthetic reference signal
First Claim
1. An oximeter for determining an estimate of the blood oxygen saturation level in the body of a patient, by processing red and infrared electrical signals acquired by a sensor arrangement upon application of red and infrared light towards a well perfused portion of the body of the patient, which electrical signals comprises a desired pulsatile component and an undesired noise component, comprising:
- a sensor arrangement for acquiring red and infrared electrical signals;
a signal generator for operating independently of said acquired red and infrared electric signals, for providing a predetermined synthetic reference signal that is expected to exhibit a correlation with the desired pulsatile component of the acquired red and infrared electrical signals;
an adaptive filter arrangement having a first input responsive to said acquired red and infrared electrical signals, and a second input responsive to said synthetic reference signal, said adaptive filter arrangement operating in a feedback manner so as to iteratively adjust the applied synthetic reference signal so as to progressively generate as an output of the filter arrangement more accurate approximations of the desired pulsatile component of the acquired red and infrared electrical signals; and
a saturation estimate processor for processing said more accurate approximations of the desired pulsatile component of the acquired red and infrared electrical signals, to develop a saturation estimate of the blood oxygen saturation level in the body of the patient.
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Accused Products
Abstract
An adaptive filtering method and apparatus for reducing the level of an undesired noise component in an acquired physiological signal having a desired signal component. The acquired physiological signal is applied to one input of the adaptive filter, and a synthetic reference signal that is modeled so as to exhibit a correlation with the desired signal component is applied to another input of the adaptive filter. Thereafter, in a feedback manner, the adaptive filter iteratively adjusts the modeled synthetic reference signal so as to progressively generate a more accurate approximation of the desired signal component in the adaptive filter, which approximation becomes a reconstruction of the acquired physiological signal wherein the level of the undesired noise component is reduced.
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Citations
12 Claims
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1. An oximeter for determining an estimate of the blood oxygen saturation level in the body of a patient, by processing red and infrared electrical signals acquired by a sensor arrangement upon application of red and infrared light towards a well perfused portion of the body of the patient, which electrical signals comprises a desired pulsatile component and an undesired noise component, comprising:
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a sensor arrangement for acquiring red and infrared electrical signals; a signal generator for operating independently of said acquired red and infrared electric signals, for providing a predetermined synthetic reference signal that is expected to exhibit a correlation with the desired pulsatile component of the acquired red and infrared electrical signals; an adaptive filter arrangement having a first input responsive to said acquired red and infrared electrical signals, and a second input responsive to said synthetic reference signal, said adaptive filter arrangement operating in a feedback manner so as to iteratively adjust the applied synthetic reference signal so as to progressively generate as an output of the filter arrangement more accurate approximations of the desired pulsatile component of the acquired red and infrared electrical signals; and a saturation estimate processor for processing said more accurate approximations of the desired pulsatile component of the acquired red and infrared electrical signals, to develop a saturation estimate of the blood oxygen saturation level in the body of the patient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification