US 10,891,719 B2  
Systems, methods and programs for denoising signals using wavelets  
Madhur Srivastava, Ithaca, NY (US); Jack H. Freed, Ithaca, NY (US); and C. Lindsay Anderson, Ithaca, NY (US)  
Assigned to CORNELL UNIVERSITY, Ithaca, NY (US)  
Appl. No. 16/301,209 

Filed by CORNELL UNIVERSITY, Ithaca, NY (US)  
PCT Filed May 11, 2017, PCT No. PCT/US2017/032174 § 371(c)(1), (2) Date Nov. 13, 2018, PCT Pub. No. WO2017/197123, PCT Pub. Date Nov. 16, 2017. 

Claims priority of provisional application 62/334,626, filed on May 11, 2016.  
Prior Publication US 2019/0287220 A1, Sep. 19, 2019  
Int. Cl. G06T 5/00 (2006.01); A61B 5/00 (2006.01); G06F 17/14 (2006.01); G06T 5/10 (2006.01) 
CPC G06T 5/002 (2013.01) [A61B 5/7203 (2013.01); A61B 5/726 (2013.01); G06F 17/148 (2013.01); G06T 5/10 (2013.01); G06T 2207/20016 (2013.01); G06T 2207/20064 (2013.01)]  30 Claims 
1. A method of denoising a signal comprising: transforming a signal using a discrete wavelet transformation into a first wavelet component and a second wavelet component for each of a plurality of different resolutions, respectively, using preset wavelets, each of the first wavelet component and the second wavelet component having a plurality of coefficients;
determining a number of different resolutions, where the number is k, of the plurality of different resolutions for use in thresholding by examining at least coefficients for the first wavelet component for at least two of the plurality of different resolutions, respectively;
for each of the determined number of different resolutions for use in thresholding, comparing each coefficient in the first wavelet component with a variable threshold, the variable threshold for each of the determined number of different resolutions being different, and selectively changing a value of the coefficient based on the comparison thereby generating a modified first wavelet component having changed coefficients and unchanged coefficients;
for the kth different resolution, comparing each coefficient in the second wavelet component with a second variable threshold, and selectively changing a value of the coefficient based on the comparison, thereby generating a modified second wavelet component having changed coefficients and unchanged coefficients; and
transforming, using an inverse discrete wavelet transformation, the modified first wavelet component for each of the determined number of resolutions and the modified second wavelet component into a denoised signal.
