Find the columns where a certain number is repeated consecutively

I have a matrix of ones and zeros of an Image (690 x 1100)

I need to find the columns where at least 50 zeros are repeated.

Can someone help me?

[Jan]

Does "50 zeros are repeated" mean a consecutive zeros?

[Yaisel Córdova Chávez]

Yes, 50 consecutive zeros

Answer 1

[Jonas]

quick and dirty small example

a=[ 1 1 1 0 1;...
    0 1 1 0 1;...
    0 0 1 1 1;...
    0 1 1 1 1];
nrOfMinZerosPerCol=2;
colsWithRepetitions=~all(conv2(a,ones(nrOfMinZerosPerCol,1),'valid'),1);

[Yaisel Córdova Chávez]

Thank you very much for your answer Jonas. I had found a way with two for, but this is faster and more efficient.