Signal processing apparatus and method
DCFirst Claim
1. In a signal processor, a method of determining measurements for one or more blood parameters of pulsing blood, the method comprising:
- receiving a first intensity signal from a light-sensitive detector which detects light of a first wavelength attenuated by body tissue carrying pulsing blood;
receiving a second intensity signal from the light-sensitive detector which detects light of a second wavelength attenuated by body tissue carrying pulsing blood;
electronically transforming the first and second intensity signals into the frequency domain;
electronically determining values of the transformed first and second intensity signals that represent desired physiological data;
electronically combining the transformed first and second intensity signals to form a composite signal comprising physiological information from both the transformed first and second intensity signals; and
electronically analyzing the composite signal using one or more physiologically-based rules; and
electronically determining the measurement of the blood parameter based at least in part on results of the analysis.
3 Assignments
Litigations
0 Petitions
Accused Products
Abstract
A method and an apparatus to analyze two measured signals that are modeled as containing desired and undesired portions such as noise, FM and AM modulation. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, a transformation is used to evaluate a ratio of the two measured signals in order to find appropriate coefficients. The measured signals are then fed into a signal scrubber which uses the coefficients to remove the unwanted portions. The signal scrubbing is performed in either the time domain or in the frequency domain. The method and apparatus are particularly advantageous to blood oximetry and pulserate measurements. In another embodiment, an estimate of the pulserate is obtained by applying a set of rules to a spectral transform of the scrubbed signal. In another embodiment, an estimate of the pulserate is obtained by transforming the scrubbed signal from a first spectral domain into a second spectral domain. The pulserate is found by identifying the largest spectral peak in the second spectral domain.
-
Citations
65 Claims
-
1. In a signal processor, a method of determining measurements for one or more blood parameters of pulsing blood, the method comprising:
-
receiving a first intensity signal from a light-sensitive detector which detects light of a first wavelength attenuated by body tissue carrying pulsing blood; receiving a second intensity signal from the light-sensitive detector which detects light of a second wavelength attenuated by body tissue carrying pulsing blood; electronically transforming the first and second intensity signals into the frequency domain; electronically determining values of the transformed first and second intensity signals that represent desired physiological data; electronically combining the transformed first and second intensity signals to form a composite signal comprising physiological information from both the transformed first and second intensity signals; and electronically analyzing the composite signal using one or more physiologically-based rules; and electronically determining the measurement of the blood parameter based at least in part on results of the analysis. - View Dependent Claims (2, 3, 4)
-
-
5. In a signal processor, a method of performing a measurement of a blood parameter of pulsing blood, the method comprising:
-
receiving first and second intensity signals from a light-sensitive detector which detects light of at least first and second wavelengths attenuated by body tissue carrying pulsing blood, the first and second intensity signals comprising desired physiological signal portions and patient motion-induced noise portions; electronically transforming the first and second intensity signals into the frequency domain; electronically combining the transformed first and second intensity signals to form a composite signal comprising physiological information from both the transformed first and second intensity signals; electronically analyzing the composite signal using one or more physiologically-based rules; and electronically determining the measurement of the blood parameter based at least in part on results of the analysis. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
-
-
33. An apparatus for performing a measurement of a blood parameter of pulsing blood, the apparatus comprising:
-
an input port configured to accept first and second intensity signals from a light-sensitive detector which detects light of at least first and second wavelengths attenuated by body tissue carrying pulsing blood, the first and second intensity signals comprising desired physiological signal portions and patient motion-induced noise portions; a processor configured to perform a method comprising; transforming the first and second intensity signals into the frequency domain; combining the transformed first and second intensity signals to form a composite signal comprising physiological information from both the transformed first and second intensity signals; analyzing the composite signal using one or more physiologically-based rules; and determining the measurement of the blood parameter based at least in part on results of the analysis; and an output port configured to output the measurement of the blood parameter. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55)
-
-
56. A physiological monitor adapted to be attached to a living being, said monitor comprising:
-
a detector responsive to physiological properties relating to a blood parameter of pulsing blood, said detector producing a detector output waveform; a signal processor operatively coupled to said detector, said signal processor receiving said detector output waveform, said signal processor configured to; transform said detector output waveform into a spectral domain waveform; identify a series of spectral peaks, and peak frequencies corresponding to said spectral peaks, in said spectral domain waveform; and apply a plurality of rules to said spectral peaks and said peak frequencies in order to determine an estimate for said blood parameter and to determine a confidence value representative of a degree of confidence in the accuracy of said estimate for said blood parameter; and an output configured to output said estimate for said blood parameter. - View Dependent Claims (57, 58, 59, 60, 61, 62, 63, 64, 65)
-
Specification