Devices and methods for real-time denoising of electrocardiograms

Abstract

Apparatuses and methods (including methods of using such apparatuses) for de-noising electrocardiograms (ECGs) by manually or automatically adjusting the amount of filtering of an ECG signal. For example, real-time ECG signals may be filtered by combining in a weighted fashion an unfiltered portion of an ECG (or a filtered portion of the same ECG) with the same portion of the ECG that has been filtered. The weighting may be adjusted manually and/or automatically. Also described herein are methods for real-time filtering of ECG signals using a combination of filtering techniques including filtering to correct baseline wander, Savitzky-Golay denoising, and threshold smoothing. Multiple filtering techniques may be combined in a weighed manner to provide signal de-noising.

What is claimed is: 
     
         1 . A method of processing an electrocardiogram (ECG) signal of a user to provide improved readability of the ECG signal for a medical professional in diagnosing the ECG signal, the method comprising:
 receiving an ECG signal; and   filtering the ECG signal as the ECG signal is received by applying a first filtering stage, a second filtering stage, and a third filtering stage to the ECG signal, wherein the first, second, and third filtering stages are different from one another.   
     
     
         2 . The method of  claim 1 , further comprising displaying the filtered ECG signal in real-time as the ECG signal is received and filtered, wherein the displayed filtered ECG signal has improved readability such that a medical professional can better diagnose the filtered ECG signal. 
     
     
         3 . The method of  claim 1 , wherein the first, second, and third filtering stages are performed in sequence. 
     
     
         4 . The method of  claim 1 , wherein the first, second, and third filtering stages are performed in parallel. 
     
     
         5 . The method of  claim 1 , wherein applying the first filtering stage comprises removing baseline wander of the ECG signal. 
     
     
         6 . The method of  claim 5 , wherein removing the baseline wander comprises removing a moving average of the ECG signal from a portion of the ECG signal. 
     
     
         7 . The method of  claim 1 , wherein applying the second filtering stage comprises removing high-frequency noise from the ECG signal. 
     
     
         8 . The method of  claim 7 , wherein removing the high-frequency noise comprises applying a Savitzky-Golay de-noising filter to smooth the ECG signal. 
     
     
         9 . The method of  claim 8 , wherein applying the Savitzky-Golay de-noising filter comprises applying a high order Savitzky-Golay filter to a QRS segment of the ECG signal and applying a low order Savitzky-Golay filter to a non-QRS segment of the ECG signal. 
     
     
         10 . The method of  claim 1 , wherein applying the third filtering stage comprises removing low-amplitude, high frequency noise from the ECG signal. 
     
     
         11 . The method of  claim 10 , wherein removing the low-amplitude, high frequency noise from the ECG signal comprises applying threshold fit smoothing to the ECG signal. 
     
     
         12 . The method of  claim 1 , further comprising pre-processing the received ECG signal before filtering the ECG signal. 
     
     
         13 . The method of  claim 12 , wherein pre-processing the received ECG signal comprises applying user-selected mains filter. 
     
     
         14 . The method of  claim 1 , further comprising detecting an amount of noise of the received ECG signal. 
     
     
         15 . The method of  claim 14 , further comprising varying an amount of filtering applied to the received ECG signal in response to the amount of noise detected. 
     
     
         16 . The method of  claim 14 , wherein detecting the amount of noise comprises training a module of a computing device with a noise model. 
     
     
         17 . The method of  claim 1 , further comprising varying an amount of filtering applied to the received ECG signal in response to user input. 
     
     
         18 . A method of processing an electrocardiogram (ECG) signal of a user to provide improved readability of the ECG signal for a medical professional in diagnosing the ECG signal, the method comprising:
 providing an ECG signal to a computing device;   filtering the provided ECG signal;   displaying the filtered ECG signal on a display of the computing device; and   varying an amount of filtering applied to the displayed ECG signal in response to user input, wherein the amount of filtering is varied in real-time as the ECG signal is displayed, and wherein the displayed filtered ECG signal has improved readability such that a medical professional can better diagnose the filtered ECG signals.   
     
     
         19 . The method of  claim 18 , wherein providing the ECG signal comprises receiving, with the computing device, the ECG signal as the ECG signal is measured from an ECG sensor coupled to the computing device. 
     
     
         20 . The method of  claim 18 , wherein providing the ECG signal comprises receiving, with the computing device, the ECG signal as the ECG signal is measured from an onboard sensor of the computing device. 
     
     
         21 . The method of  claim 18 , wherein the ECG signal is displayed in real-time as the ECG signal is provided and filtered. 
     
     
         22 . The method of  claim 18 , wherein filtering the displayed ECG signal comprises applying a first filtering stage, a second filtering stage, and a third filtering stage to the provided ECG signal, wherein the first, second, and third filtering stage are different from one another. 
     
     
         23 . The method of  claim 18 , wherein the computing device comprises one or more of a smartphone, a tablet computer, a laptop computer, a personal computer, a personal digital assistant, or a wearable computer. 
     
     
         24 . A method of processing an electrocardiogram (ECG) signal of a user, the method comprising:
 receiving an ECG signal;   pre-processing the received ECG signal; and   filtering the pre-processed ECG signal by (i) removing baseline wander of the ECG signal, (ii) removing high frequency noise from the ECG signal, and (iii) removing low-amplitude, high frequency noise from the ECG signal, wherein steps (i) to (iii) are performed sequentially.