pre allocating variables in matlab

i have this block of code but when i access elements, they are not arranged properly

x=zeros(1,10000);
y=zeros(1,10000);
count=1;
for i=1:rows
    for j=1:columns  
      if imgThresh(i,j)==0
        y(count)=rows-i+1;
        x(count)=j;
        count=count+1;
         break
      end
    end
end
nonzeros(x)
nonzeros(y)

[James Tursa]

You need to give us a small example of input and desired output. Please describe specifically what it is about the output of your current code that you don't like. What are you trying to do?

[emeka onwochei]

it supposed to read the binary image pixels and stores the cell of the first black box, it uses the points to draw a shape. it gives me the blue curve below.

Answer 1

[Walter Roberson]

That's not what I get.

imgThresh = im2bw(imread('image.png'));

rows = size(imgThresh,1);
columns = size(imgThresh,2);

x=zeros(1,10000);
y=zeros(1,10000);
count=1;
for i=1:rows
    for j=1:columns  
      if imgThresh(i,j)==0
        y(count)=rows-i+1;
        x(count)=j;
        count=count+1;
         break
      end
    end
end

plot(x,y)

[emeka onwochei]

this is for the second part,

for i=1:rows
    for j=fliplr(1:columns)  
      if imgThresh(i,j)==0
        y(count)=rows-i+1;
        x(count)=j;
         count=count+1;
         break
      end
    end
end