function [contour,I1]=png2contour(I)

A=rgb2gray(I);

[x1,y1]=size(A);

I1=A(:,501:end-502);

[x,y]=size(I1);

count=0;

for i=1:x

    for j=1:y

        if I1(i,j)==150

            count=count+1;

            new_x(count)=j;

            new_y(count)=i;

        end

    end

end

contour(:,1)=new_x*256/x1;

contour(:,2)=new_y*256/x1;

end