Find runs of repeated ones of any length and put into a cell array to compare indices

Hello,

I have two logical arrays, A & B, of size 370x23. They are the ouputs from two different functions performed on the same matrix, C.

A contains long runs of 1s while B contains 1-5 (approx) 1s in a row at a time.

I want to find strings of 1s (or rund of consecutive 1s) of any length in A to check if their indices overlap at all with B. If the strings in A contain B, then I want to keep the entire string of 1s in A. If they don't, then the whole string goes to 0s.

Another way to ask this would be how to group strings of 1s and then use their indices to check overlap with another set of indices.

Thanks youse.

Answer 1

[Sahithi Kanumarlapudi]

Hi,

You could use the 'find' function to find the indices at which the 1's are present and compare those indices.

For more information on how to use find function refer to the following link

https://www.mathworks.com/help/matlab/ref/find.html

[Teddy Fisher]

Hi thanks! How would I compare the indices once I have done that? My problem is how to group together the consecutive indices and check for overlap and then zero out if there is no overlap

[Teddy Fisher]

Hi, I found the answer to my question in another thread and I have come up with code to find the consecutive indices

A= [1 2 3 4 14 15 23 24 25 ]   % your array of values
A(end+1)=2   % adds new endpoint to very end of A so code picks up end of last group of consecutive values
I_1=find(diff(A)~=1);  % finds where sequences of consecutive numbers end
[m,n]=size(I_1);   % finds dimensions of I_1 i.e. how many sequences of consecutive numbers you have
startpoint=1;    % sets start index at the first value in your array
seq=cell(1,n)  % had to preallocate because without, it only saved last iteration of the for loop below
               % used n because this array is a row vector
for i=1:n
    End_Idx=I_1(i);   %set end index
    seq{i}=A(startpoint:End_Idx);  %finds sequences of consecutive numbers and assigns to cell array
    startpoint=End_Idx+1;   %update start index for the next consecutive sequence
end

I will update this once I figure out how to compare A&B

[Image Analyst]

Teddy, this is trivial with regionprops() in the Image Processing Toolbox.

[Teddy Fisher]

I looked up the documentation for regionprops and I don't see how that would be done. Any advice?