Press the "Start" button to see a demonstration of denoising tools in the Wavelet Toolbox. This demo uses Wavelet Toolbox functions. % Set signal to noise ratio and set rand seed. sqrt_snr = 3; init = 2055615866; % Generate original signal and a noisy version adding % a standard Gaussian white noise. [xref,x] = wnoise(3,11,sqrt_snr,init); % Denoise noisy signal using soft heuristic SURE thresholding % and scaled noise option, on detail coefficients obtained % from the decomposition of x, at level 5 by sym8 wavelet. % Generate original signal and a noisy version adding % a standard Gaussian white noise. lev = 5; xd = wden(x,'heursure','s','one',lev,'sym8'); % Denoise noisy signal using soft SURE thresholding. xd = wden(x,'rigrsure','s','one',lev,'sym8'); % Denoise noisy signal using fixed form threshold with % a single level estimation of noise standard deviation. xd = wden(x,'sqtwolog','s','sln',lev,'sym8'); % Denoise noisy signal using fixed minimax threshold with % a multiple level estimation of noise standard deviation. xd = wden(x,'minimaxi','s','sln',lev,'sym8'); % If many trials are necessary, it is better to perform % decomposition one time and threshold it many times : % decomposition. [c,l] = wavedec(x,lev,'sym8'); % threshold the decomposition structure [c,l]. xd = wden(c,l,'minimaxi','s','sln',lev,'sym8'); % Load electrical signal and select a part. load leleccum; indx = 2600:3100; x = leleccum(indx); % Use wdencmp for signal de-noising. % find default values (see ddencmp). [thr,sorh,keepapp] = ddencmp('den','wv',x); % denoise signal using global thresholding option. xd = wdencmp('gbl',x,'db3',2,thr,sorh,keepapp); % Some trial examples without commands counterpart. % Rand initialization: init = 2055615866; % Square root of signal to noise ratio: sqrt_snr = 5; % [xref,x] = wnoise(1,11,sqrt_snr,init); % Some trial examples without commands counterpart (more). % Rand initialization: init = 2055615866; % Square root of signal to noise ratio: sqrt_snr = 4; % [xref,x] = wnoise(2,11,sqrt_snr,init); % Some trial examples without commands counterpart (more). % Rand initialization: init = 2055615866; % Square root of signal to noise ratio: sqrt_snr = 3; % [xref,x] = wnoise(3,11,sqrt_snr,init); % Some trial examples without commands counterpart (more). % Rand initialization: init = 2055615866; % Square root of signal to noise ratio: sqrt_snr = 3; % [xref,x] = wnoise(3,11,sqrt_snr,init); % Some trial examples without commands counterpart (more). % Rand initialization: init = 2055615866; % Square root of signal to noise ratio: sqrt_snr = 3; % [xref,x] = wnoise(3,11,sqrt_snr,init); % Some trial examples without commands counterpart (more). % Rand initialization: init = 2055615866; % Square root of signal to noise ratio: sqrt_snr = 3; % [xref,x] = wnoise(3,11,sqrt_snr,init);