Patent ID: 7672717

Claim:
A system for removing artifacts from an observed electrogram of a subject in order to produce a denoised electrogram, given a time-frequency transform, and given a database of reference electrograms, each said reference electrogram being free of said artifacts, and each said reference electrogram having been acquired from individuals other than said subject, said system comprising: a. a sensor for acquiring the electrogram of said subject to complement said database of reference electrograms, and for producing said observed electrogram; and b. a digital signal processor for: i. applying said time-frequency transform to said reference electrograms to produce a plurality of reference coefficient sets, each said reference coefficient set corresponding to a respective time-frequency span; ii. calculating a threshold for each said time-frequency span based on a corresponding reference coefficient set; iii. applying said time-frequency transform to said observed electrogram to produce a plurality of observed coefficient sets, each said observed coefficient set corresponding to a respective time-frequency span; iv. comparing each coefficient of each said observed coefficient set with the corresponding threshold for a respective time-frequency span; v. replacing every large coefficient of each said observed coefficient set which is above the respective threshold for the corresponding time-frequency span with a replacement value in order to produce denoised observed coefficient sets; and vi. applying the inverse transform of said time-frequency transform to said denoised observed coefficient sets to reconstruct the denoised electrogram.