Automatic Computation of Interval-Dependent Thresholds on an imported .wav file.

I have followed the matlab documentation on this and tried to adapt it to my needs but i get these errors that occur within the functions i am using:

Error using cat

Dimensions of arrays being concatenated are not consistent.

Error in wrepcoef (line 37)

varargout{1} = cat(dim,repcoefs{:});

Error in utthrset_cmd (line 24)

details = wrepcoef(coefs,longs);

This is my code:

clc;

[pete1,fs] = audioread("noisypete.wav");

peterch1 = pete1(:,1);

peterch2 = pete1(:,2);

wname = 'sym6';

level = 5;

[coefs,longs] = wavedec(peterch1,level,wname);

siz = size(coefs);

thrParams = utthrset_cmd(coefs,longs);

first = cumsum(longs)+1;

first = first(end-2:-1:1);

tmp = longs(end-1:-1:2);

last = first+tmp-1;

for k = 1:level

thr_par = thrParams{k};

if ~isempty(thr_par)

cfs = coefs(first(k):last(k));

nbCFS = longs(end-k);

NB_int = size(thr_par,1);

x = [thr_par(:,1) ; thr_par(NB_int,2)];

alf = (nbCFS-1)/(x(end)-x(1));

bet = 1 - alf*x(1);

x = round(alf*x+bet);

x(x<1) = 1;

x(x>nbCFS) = nbCFS;

thr = thr_par(:,3);

for j = 1:NB_int

if j==1

d_beg = 0;

else

d_beg = 1;

end

j_beg = x(j)+d_beg;

j_end = x(j+1);

j_ind = (j_beg:j_end);

cfs(j_ind) = wthresh(cfs(j_ind),sorh,thr(j));

end

coefs(first(k):last(k)) = cfs;

end

end

sigden = waverec(coefs,longs,wname);

figure

subplot(2,1,1)

plot(peterch1,'r')

axis tight

hold on

plot(sigden,'k')

title('Original and Denoised Signals')

subplot(2,1,2)

plot(sigden,'k')

axis tight

hold off

title('Denoised Signal')

from inspecting the issue in dimension within the wrepcoef function, it seems that maybe the bookkeeping vector, 'longs' is a double instead of a single as the 'dim' is set to 1 in the wrepcoef function. if so, could you recommend a solution to this? this is for a university project.

thank you

Answer 1

[Sai Pavan]

Hello Zayne,

I understand that you want to resolve the error occuring with the use of 'utthrset_cmd' function.

As the error "Dimensions of arrays being concatenated are not consistent" suggests, the issue here is with the dimensions of the input data sent to the function. The issue is resolved by transposing the "coefs" array and sending it as an input to the 'utthrset_cmd' function along with 'longs' array.

Please refer to the modified code snippet shown below:

thrParams = utthrset_cmd(coefs',longs); % coefs array is transposed

Please refer to the below documentation to learn more about transpose operation: https://www.mathworks.com/help/matlab/ref/transpose.html

Hope it helps!