Length consecutive value 1 within a 2D matrix

Having a 2 dimensional array, e.g.

[ 0, 0, 0,1,1,1,2 ;

0,0,1,1,1,1,2;

0,1,1,1,1,1,0;

0,0,0,1,1,0,0]

I want for each row the length of consecutive 1

In this case R1 = 3, R2= 4, R3=5,R4=2.

[Jan]

Are several runs possible as in [0,1,1,0,1,1]?

Answer 1

[Image Analyst]

Try this: I've made it general and put the results into a cell array in case some row has more than one region of 1's, like it might have 2 or 5 or 20 runs of 1's.

m = [   0, 0, 0,1,1,1,2 ;
    0,0,1,1,1,1,2;
    0,1,1,1,1,1,0;
    0,0,0,1,1,0,0;
    1,1,0,1,1,1,0] % Last row has 2 contiguous regions instead of 1.
mb = m == 1
[rows, columns] = size(mb);
for row = 1 : rows
    % Make measurements of all lines of 1's.
    props = regionprops(mb(row, :), 'Area');
    % Extract all the lengths into a vector and then put into a cell.
    R{row} = [props.Area];
end
R % Shows in command window

R =

1×5 cell array

{[3]} {[4]} {[5]} {[2]} {[2 3]}

If you know in advance that there is just one run of 1's per row then you can use just a regular (non-cell array) vector:

m = [   0, 0, 0,1,1,1,2 ;
    0,0,1,1,1,1,2;
    0,1,1,1,1,1,0;
    0,0,0,1,1,0,0] % Last row has 2 contiguous regions instead of 1.
mb = m == 1
[rows, columns] = size(mb);
for row = 1 : rows
    % Make measurements of all lines of 1's.
    props = regionprops(mb(row, :), 'Area');
    % Extract all the lengths into a vector and then put into a cell.
    R(row) = [props.Area];
end
R

Shows

R =

3 4 5 2

[Odo Luo]

Thank you , this helped me a lot !!