How to mark periods in my matrices?

Hello,

Since I am new in Data Analysis, I need some help marking periods of consecutieve 1's.

for i=1:length(PD) 
for isessions=1:PD(i).TotSessionsVid
[PD(i).FakeMatrix(isessions).Random] = randi([0 1], 10000,4);
for iconfig=1:length(PD(i).FakeMatrix(isessions).Random)
if PD(i).FakeMatrix(isessions).Random(iconfig, :) == [1 1 1 1]
   PD(i).FakeMatrix(isessions).Random2(iconfig, :) = [PD(i).FakeMatrix(isessions).Random(iconfig, :), 1];
elseif PD(i).FakeMatrix(isessions).Random(iconfig, :) == [1 1 1 0]
   PD(i).FakeMatrix(isessions).Random2(iconfig, :) = [PD(i).FakeMatrix(isessions).Random(iconfig, :), 1];
elseif PD(i).FakeMatrix(isessions).Random(iconfig, :) == [1 1 0 0]
   PD(i).FakeMatrix(isessions).Random2(iconfig, :) = [PD(i).FakeMatrix(isessions).Random(iconfig, :), 1];
elseif PD(i).FakeMatrix(isessions).Random(iconfig, :) == [1 0 1 0]
   PD(i).FakeMatrix(isessions).Random2(iconfig, :) = [PD(i).FakeMatrix(isessions).Random(iconfig, :), 1];
else
   PD(i).FakeMatrix(isessions).Random2(iconfig, :) = [PD(i).FakeMatrix(isessions).Random(iconfig, :), 0];
end
end
end
end

This is my code and my goal is to find for example 5 (or as many as I want) consecutieve 1's in the 5th column of the Random2 FakeMatrices. How can I do that? I have tried && statements combined with if statements, but I believe this can be more efficient. Can anyone help me? I want to mark them as 'on'.

[jonas]

Ugh, that code is hard to read. Can you explain the question in more detail? Probably you can solve it without so many loops

[JamJan]

I'm sorry, it is quite a big data set with lots of participants and lots of sessions. :) It is as simple as this: for example I have a matrix:

1  1  1  1  1
1  1  0  0  1
1  0  1  0  1
0  1  1  0  0
0  0  1  0  0
1  0  1  0  1
0  0  1  1  0
1  0  0  0  0
1  1  0  0  1
1  0  1  0  1
1  1  0  0  1
1  1  0  0  1
0  0  0  1  0
0  0  1  0  0
0  0  1  0  0
0  0  1  1  0

And I want to mark the periods with consecutive 1's in column 5 (for example 4 in a row) as 'on' and the rest as 'off' in a new column behind this matrix. Is this more clear? I hope so!

[jonas]

A bit, can you just also specify the exact output you want for col 5?

[JamJan]

for example: This could be the output of the Matrix:

col 1 col2    col3    col4  col5 col6
  1  1  1  1  1 on
  1  1  0  0  1 on
  1  0  1  0  1 on 
  0  1  1  0  0 off
  0  0  1  0  0 off
  1  0  1  0  1 off
  0  0  1  1  0 off
  1  0  0  0  0 off
  1  1  0  0  1 on
  1  0  1  0  1 on
  1  1  0  0  1 on
  1  1  0  0  1 on
  0  0  0  1  0 off
  0  0  1  0  0 off 
  0  0  1  0  0 off
  0  0  1  1  0 off

Answer 1

[jonas]

If you have the image processing toolbox, you can use the function bwconncomp to find connected 1's. Using the example in the comments, this script finds segments where there are 3 or more consecutive 1's, and fills the output vector with 1's (indicating 'on')

CC=bwconncomp(M(:,5),4)
size(CC.PixelIdxList)
for i=1:numel(CC.PixelIdxList)
    if numel(CC.PixelIdxList{i})>=3
        out(CC.PixelIdxList{i})=1
    end
end

If you do not have the image processing toolbox, you can use this solution instead.

%%Find at least 3 consecutive 1's
target=ones(1,3);
pos = strfind(M(:,5)',target);
out=zeros(size(M(:,5)));
for i=1:numel(pos)
    out(pos(i):pos(i)+2)=1;
end

You can change the target to any number of consecutive 1's. You can also find other patterns, such as [1 0 1], but you will have to tweak the for-loop a bit.

[JamJan]

Unfortunately I don't, However this puts me somewhat in the right direction, thank you!

[jonas]

No problem! I've updated the solution

[JamJan]

Thanks!!! However, it seems that it places 4 ones when it sees 4 consecutive ones? I think it then should be like this

%%Find at least 3 consecutive 1's
target=ones(1,3);
pos = strfind(M(:,5)',target);
out=zeros(size(M(:,5)));
for i=1:numel(pos)
    out(pos(i):pos(i)+2)=1;
end

Anyway, thanks this helps a lot!

[jonas]

Ah yes, that's correct. Updated the solution!