wavelet denoising of signal

for i=1:21;

j=1:21;

C(i) = wdenoise(C,j, ...

Wavelet='sym1', ...

DenoisingMethod='Bayes', ...

ThresholdRule='Hard', ...

NoiseEstimate='LevelIndependent');

I want to denoise my signal but before that I want to check multiple denoising methods for my data. Can you please suggest how can I change value of each wavelet & denoising method, threshold rule etc using loop. So that after each loop it store denoised signal in an array Thanks

end

Answer 1

[Voss]

Wavelet Signal Denoiser.

Alternatively, something like this may be similar to what you had in mind:

C = randn(1,100);

methods = ["Bayes" "BlockJS" "FDR" "Minimax" "SURE" "UniversalThreshold"];
rules = ["James-Stein" "Soft" "Hard" "Median" "Mean"];
levels = 1:floor(log2(numel(C)));

n_methods = numel(methods);
n_rules = numel(rules);
n_levels = numel(levels);

result = cell(n_methods,n_rules,n_levels);

for jj = 1:n_methods
    switch methods(jj)
        case "Bayes"
            valid_rules = ["Median" "Mean" "Soft" "Hard"];
        case "BlockJS"
            valid_rules = "James-Stein";
        case "FDR"
            valid_rules = "Hard";
        otherwise
            valid_rules = ["Soft" "Hard"];
    end
    [~,rules_idx] = ismember(valid_rules,rules);
    for kk = 1:numel(rules_idx)
        for ii = 1:n_levels
            try
                result{jj,rules_idx(kk),ii} = wdenoise(C,levels(ii), ...
                    Wavelet='sym1', ...
                    DenoisingMethod=methods(jj), ...
                    ThresholdRule=rules(rules_idx(kk)), ...
                    NoiseEstimate='LevelIndependent');
            catch e
                msg = sprintf('Unable to wdenoise with method %s, rule %s, level %d:\n%s', ...
                    methods(jj),rules(rules_idx(kk)),levels(ii),e.message);
                disp(msg);
            end
        end
    end
end

Unable to wdenoise with method BlockJS, rule James-Stein, level 6:
For block thresholding, the level of the wavelet transform must be less than or equal to 5.

for jj = 1:n_methods
    figure()
    t = tiledlayout(n_levels,n_rules,'TileSpacing','none');
    t.Title.String = sprintf('Method: %s',methods(jj));
    t.YLabel.String = 'Level:';
    t.Subtitle.String = 'ThresholdRule:';
    for ii = 1:n_levels
        for kk = 1:n_rules
            nexttile();
            box on
            hold on
            if ii == 1
                title(rules(kk));
            end
            if kk == 1
                ylabel(sprintf('%d',levels(ii)));
            end
            if ~isempty(result{jj,kk,ii})
                plot(C)
                plot(result{jj,kk,ii})
            end
            xticklabels([])
            yticklabels([])
        end
    end
end

[MANINDER CHOUDHARY]

Thank you very much. It works (Y)

[Voss]

You're welcome!