How can I draw 117 normal 292 abnormal heart sounds?

Question

Cey 2023-4-2

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1939619-how-can-i-draw-117-normal-292-abnormal-heart-sounds

评论： Star Strider 2023-4-13

I have a total of 409 heart sounds, 117 of which are normal and 292 of which are abnormal. I have prepared separate codes normally and abnormally, how should I go about drawing each sound?

The audio files were not added because they were too large, this is the example for which I found the code: https://www.mathworks.com/matlabcentral/fileexchange/65286-heart-sound-classifier

Database: https://archive.physionet.org/pn3/challenge/2016/

For example;

% fs:2000
[PCG_normal, fs] = audioread('a0011.wav');
p_normal = audioplayer(PCG_normal, fs);
play(p_normal, [1 (get(p_normal, 'SampleRate') * 3)]);
% Plot the sound waveform
plot(PCG_normal(1:fs*3))
[PCG_abnormal, fs] = audioread('a0001.wav');
p_abnormal = audioplayer(PCG_abnormal, fs);
play(p_abnormal, [1 (get(p_abnormal, 'SampleRate') * 3)]);
%        Plot the sound waveform
plot(PCG_abnormal(1:fs*3))

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Star Strider 2023-4-2

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1939619-how-can-i-draw-117-normal-292-abnormal-heart-sounds#answer_1206939

编辑：Star Strider 2023-4-2

在 MATLAB Online 中打开

Drawing them depends on the result you want. Heart sounds are best displayed as time-frequency plots, so I would plot them using the pspectrum function with the 'spectrogram' option. (Ideally, they should be plotted along with the corresponding Lead II EKG trace.)

Plotting 409 of them might be something of a challenge, since tiledlayout and subplot would create axes that are too small to easily visualise.

EDIT — (2 Apr 2023 at 17:32)

This emphasizes the time-frequency characteristics of the phonocardiogram signals —

Uz1 = unzip('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1342909/heart%20sound.zip');

Uz2 = unzip('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1342914/records.zip');

[PCG_normal, fsn] = audioread(Uz1{2});

p_normal = audioplayer(PCG_normal, fsn);

Ln = size(PCG_normal,1);

tn = linspace(0, Ln-1, Ln)/fsn;

play(p_normal, [1 (get(p_normal, 'SampleRate') * 3)]);

% Plot the sound waveform

figure

plot(PCG_normal(1:fsn*3))

[PCG_abnormal, fsa] = audioread(Uz1{1});

p_abnormal = audioplayer(PCG_abnormal, fsa);

La = size(PCG_abnormal,1);

ta = linspace(0, La-1, La)/fsa;

play(p_abnormal, [1 (get(p_abnormal, 'SampleRate') * 3)]);

% Plot the sound waveform

figure

plot(PCG_abnormal(1:fsa*3))

figure

tiledlayout(2,2)

nexttile

pspectrum(PCG_normal, fsn,'spectrogram')

colormap(turbo)

nexttile

pspectrum(PCG_abnormal, fsa,'spectrogram')

colormap(turbo)

nexttile

plot(tn,PCG_normal)

xlabel('t')

ylabel('Amplitude')

title('PCG Normal')

xlim([0 max(tn)])

grid

nexttile

plot(ta,PCG_abnormal)

xlabel('t')

ylabel('Amplitude')

title('PCG Abnormal')

xlim([0 max(ta)])

grid

.

10 个评论
显示 8更早的评论隐藏 8更早的评论

Star Strider 2023-4-3

My pleasure!

There is nothing to be gained by filtering them, especially with those filter passbands (that appear to be normalised, so equate to 20-400 and 20-800 Hz, respectively). As is apparent in the spectrogram plots, there is little appreciable noise, and much of the most relevant information would be filtered out with those filters (for example the high-frequency component at about 850 Hz in the ‘abnormal’ record). I wouild also do spectrogram plots on several of the ’abnormal’ records to be certain that the spectral characteristic are relatively constant. Systolic ejection murumurs have a high-frequency component, however the low-frequency diastolic rumble present in atrial septal defect phonocardiograms, in addition to the widely-split second heart sound, would be worth additional consideration if those records are present in the ‘abnormal’ set.

So for signal processing purposes, I would just leave them as they are.

If you want to classify them or do some other sort of feature segmentation, I would choose two (or more) filters with slightly overlapping passbands, perhaps 20-500 Hz and 500-950 Hz, and then compute the relative power (the sum of the squared amplitudes) in those filter outputs. That should allow you to differentiate normal from abnormal phonocardiogram records (although phonocardiography is largely considered to be obsolete currently, having been replaced by ultrasound, and particularly point-of-care ultrasound, or POCUS).

The most computationally efficient filters are elliptic filters, so I would also replace the Butterworth filters with them. Start with ellipord, then ellip then zp2sos.

.

Star Strider 2023-4-10

在 MATLAB Online 中打开

normal.mat

My pleasure.

Perhaps something like this —

LD = load('normal.mat')

LD = struct with fields:

normal: [10000×1 double]

normal = LD.normal;

Fs = 2E3;

L = numel(normal);

t = linspace(0, L-1, L)/Fs;

figure

tiledlayout(2,1)

nexttile

plot(t,normal)

grid

nexttile

pspectrum(normal, Fs,'spectrogram')

colormap(turbo)

Lf = 7; % Number Of Filters+1

PBv = linspace(0.01, 0.975, Lf); % Passband Vector For 6 Filters

for k = 1:Lf-1

Wp = [PBv(k) PBv(k+1)]; % Passband Frequency (Normalised)

Ws = [0.975 1.025].*Wp; % Stopband Frequency (Normalised)

Rp = 1; % Passband Ripple

Rs = 60; % Passband Ripple (Attenuation)

[n,Wp] = ellipord(Wp,Ws,Rp,Rs); % Elliptic Order Calculation

[z,p,kf] = ellip(n,Rp,Rs,Wp); % Elliptic Filter Design: Zero-Pole-Gain

[sos{k},g(k)] = zp2sos(z,p,kf); % Second-Order Section For Stability

figure

freqz(sos{k}, 2^16, Fs) % Filter Bode Plot

end

figure

tiledlayout(fix((Lf-1)/2),2)

for k = 1:Lf-1

y(:,k) = filtfilt(sos{k},g(k),normal); % Filter Signal

nexttile

plot(t,y(:,k))

grid

xlim([min(t) max(t)])

title(sprintf('%.2f - %.2f Hz',PBv(k),PBv(k+1)))

end

Displaying the freqz results is not absolutely necessary. I did it here to demonstrate the different segmental filters.

(It would be helpful to have the sampling frequency or time vector as one of the variables included in the .mat files. Guessing that it‘ 2k here.)

.

Cey 2023-4-13

thank you very much just as what i wanted

Star Strider 2023-4-13

My pleasure!

If my Answer helped you solve your problem, please Accept it!

.

请先登录，再进行评论。

How can I draw 117 normal 292 abnormal heart sounds?

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

采纳的回答

10 个评论
显示 8更早的评论隐藏 8更早的评论

更多回答（0 个）

另请参阅

类别

标签

Community Treasure Hunt

How can I draw 117 normal 292 abnormal heart sounds?

0 个评论 显示 -2更早的评论隐藏 -2更早的评论

采纳的回答

10 个评论 显示 8更早的评论隐藏 8更早的评论

更多回答（0 个）

另请参阅

类别

标签

Community Treasure Hunt

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

10 个评论
显示 8更早的评论隐藏 8更早的评论