How to find 5 consecutive values above threshold within a certain window?

I have a vecor A:

A = [6 7 8 8 8 7 6 7 6 2 7 8 9 3 3 4 6 7 8 9]

The threshold is 5. I want to keep all values that are above the threshold. However, if within a window of 5 values, one out of the 5 is below the threshold, that's ok and I want to keep that one too. If in a window 2 or more values are below the threshold, then I do not want those values.

Thus, the new vector B would be:

B = [6 7 8 8 8 7 6 7 6 2 4 6 7 8 9]

NB: the window moves in steps of 5, so it takes 5 elements, analyeses them, then moves to the next 5.

Answer 1

[Mathieu NOE]

hello

here you are my friend :

A = [6 7 8 8 8 7 6 7 6 2 7 8 9 3 3 4 6 7 8 9];
buffer = 5;  % nb of samples in one buffer (buffer size) 
threshold  = 5;

%%%% main loop %%%%
m = length(A);
B = [];

for ci=1:fix((m-buffer)/buffer +1)
    start_index = 1+(ci-1)*buffer;
    stop_index = min(start_index+ buffer-1,m);
    data_buffer = A(start_index:stop_index)  % 
    ind = find(data_buffer<threshold);
    if numel(ind)<2
        B = [B  data_buffer];
    end
end
B

[Mathieu NOE]

hello

problem solved ?

Answer 2

[Bruno Luong]

A = [6 7 8 8 8 7 6 7 6 2 7 8 9 3 3 4 6 7 8 9]

A = 1×20

6 7 8 8 8 7 6 7 6 2 7 8 9 3 3 4 6 7 8 9

win = 5;
threshold=5;
maxreject=3;
% Pad NaNs so that the length is multiple of win
Ap=A;
Ap(end+1:ceil(end/win)*win)=NaN; 
% Rejection
Ap=reshape(Ap,win,[]);
Ap(:,sum(Ap>threshold,1)<=maxreject)=[];
% Reshape and remove trailing NaNs
Ak=Ap(isfinite(Ap))'

Ak = 1×15

6 7 8 8 8 7 6 7 6 2 4 6 7 8 9