Biomedical signal denoising techniques
First Claim
1. An implantable medical device comprising:
- a wavelet transform unit to transform an electrogram into a set of wavelets, the set of wavelets including different subsets of wavelets for different scales; and
a wavelet denoising unit to compare first wavelet coefficients of the wavelets in a first subset to a first threshold, compare second wavelet coefficients of the wavelets in a second subset to a second threshold, the second threshold being different than the first threshold, reduce one or more of the first wavelet coefficients that are less than the first threshold, and reduce one or more of the second wavelet coefficients that are less than the second threshold.
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Accused Products
Abstract
The invention is directed to denoising techniques for electrograms, or other biomedical signals, in which wavelet transformations are used in the denoising process. For example, an electrogram can be represented by a finite set of wavelets which comprise a decomposition of the electrogram in the scale-time domain. In accordance with the invention, an electrogram can be transformed into a set of wavelets, and thresholding can be performed on the wavelets to eliminate noise while preserving the information of the electrogram. Different thresholds can be used for the wavelets in different scales for improved denoising results. If a respective threshold exceeds a wavelet coefficient, the wavelet coefficient is reduced. Following the thresholding process, the wavelets can be converted into a denoised electrogram, which can be analyzed or processed. In this manner, wavelet transformations can be exploited for effective electrogram denoising.
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Citations
33 Claims
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1. An implantable medical device comprising:
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a wavelet transform unit to transform an electrogram into a set of wavelets, the set of wavelets including different subsets of wavelets for different scales; and
a wavelet denoising unit to compare first wavelet coefficients of the wavelets in a first subset to a first threshold, compare second wavelet coefficients of the wavelets in a second subset to a second threshold, the second threshold being different than the first threshold, reduce one or more of the first wavelet coefficients that are less than the first threshold, and reduce one or more of the second wavelet coefficients that are less than the second threshold. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An implantable medical device comprising:
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a wavelet transform unit to transform a biomedical signal into a set of wavelets, the set of wavelets including different subsets of wavelets for different scales;
a wavelet denoising unit to compare first wavelet coefficients of the wavelets in a first subset to a first threshold, compare second wavelet coefficients of the wavelets in a second subset to a second threshold, the second threshold being different then the first threshold, reduce one or more of the first wavelet coefficients that are less than the first threshold, and reduce one or more of the second wavelet coefficients that are less than the second threshold.
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8. A method comprising:
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transforming an electrogram into a set of wavelets, the set of wavelets including different subsets of wavelets for different scales;
comparing first wavelet coefficients of the wavelets in a first subset to a first threshold;
comparing second wavelet coefficients of the wavelets in a second subset to a second threshold, the second threshold being different then the first threshold;
reducing one or more of the first wavelet coefficients that are less than the first threshold; and
reducing one or more of the second wavelet coefficients that are less than the second threshold. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A system comprising:
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a first medical device to record electrograms and perform denoising of the electrograms by transforming an electrogram into a set of wavelets, the set of wavelets including different subsets of wavelets for different scales, comparing first wavelet coefficients of the wavelets in a first subset to a first threshold, comparing second wavelet coefficients of the wavelets in a second subset to a second threshold, the second threshold being different then the first threshold, reducing one or more of the first wavelet coefficients that are less than the first threshold, and reducing one or more of the second wavelet coefficients that are less than the second threshold; and
a second medial device to perform threshold estimation to establish the first and second thresholds and send the first and second thresholds to the first medical device. - View Dependent Claims (16, 17)
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18. A computer readable medium comprising computer readable instructions that when executed:
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transform an electrogram into a set of wavelets, the set of wavelets including different subsets of wavelets for different scales;
compare first wavelet coefficients of the wavelets in a first subset to a first threshold;
compare second wavelet coefficients of the wavelets in a second subset to a second threshold, the second threshold being different then the first threshold;
reduce one or more of the first wavelet coefficients that are less than the first threshold; and
reduce one or more of the second wavelet coefficients that are less than the second threshold. - View Dependent Claims (19, 20, 21)
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22. An apparatus comprising:
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means for transforming an electrogram into a set of wavelets, the set of wavelets including different subsets of wavelets for different scales;
means for comparing first wavelet coefficients of the wavelets in a first subset to a first threshold;
means for comparing second wavelet coefficients of the wavelets in a second subset to a second threshold, the second threshold being different then the first threshold;
means for reducing one or more of the first wavelet coefficients that are less than the first threshold; and
means for reducing one or more of the second wavelet coefficients that are less than the second threshold. - View Dependent Claims (23, 24, 25, 26)
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27. A system comprising:
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means for transforming an electrogram into a set of wavelets, the set of wavelets including different subsets of wavelets for different scales;
means for comparing first wavelet coefficients of the wavelets in a first subset to a first threshold;
means for comparing second wavelet coefficients of the wavelets in a second subset to a second threshold, the second threshold being different then the first threshold;
means for reducing one or more of the first wavelet coefficients that are less than the first threshold; and
means for reducing one or more of the second wavelet coefficients that are less than the second threshold; and
means for selecting the first and second thresholds prior to transforming the electrogram into the set of wavelets. - View Dependent Claims (28)
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29. A method comprising:
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comparing first wavelet coefficients for first-scale wavelets representative of an electrogram to a first threshold;
comparing second wavelet coefficients for second-scale wavelets representative of the electrogram to a second threshold;
reducing the first wavelet coefficients that are less than the first threshold; and
reducing the second wavelet coefficients that are less than the second threshold, the second threshold being different than the first threshold. - View Dependent Claims (30)
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31. A method comprising:
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transforming a biomedical signal into a set of wavelets, the set of wavelets including different subsets of wavelets for different scales;
comparing first wavelet coefficients of the wavelets in a first subset to a first threshold;
comparing second wavelet coefficients of the wavelets in a second subset to a second threshold, the second threshold being different then the first threshold;
reducing one or more of the first wavelet coefficients that are less than the first threshold; and
reducing one or more of the second wavelet coefficients that are less than the second threshold. - View Dependent Claims (32, 33)
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Specification