how to extract graph in a hand written word image - matlab

Question

I have taken one hand written word image as input for my program, I want to resize that image into 100x100 after resizing am skeletonised that image and i divide that image into equal segments of 10x10 in that segment i want to find the center of mass for foreground pixels in each segments. in my program i am finding the center of mass for foreground pixel. in my algorithm which am trying to implement they told that use that center of mass as a node add it into resulting graph and add the Add edges based on edge extraction like Minimal Spanning
Tree (MST).my question is i know the center of mass of foreground pixels im my code values of x and y coordinates stored in CXX and CYY matrix using plot(CXX,CYY,'g*'); am plotting on image. but i do not know how to use that center of mass as a node add it into resulting graph and how to add edges using MST.
this is my output image:
I want to use that plotted points as a node to resulting graph, after adding that points as a node i want add the edges based on Minimum Spanning Tree. please help me to how can i add those plotted point as nodes to resulting graph and how can i add edges to those nodes using minimum spanning tree.
clc;
clear all;
close all;
X=imread('math1.jpg');
imfinfo('math1.jpg')
figure,imshow(X)
b = imresize(X,[100,100]);
si = size(b,1);
sj = size(b,2);
%figure;imshow(b);
% Binarization
th = graythresh(b);
I = im2bw(b,th);
% w = 5;
% h = 5;
% c=si/w;
% r=sj/h;
kl=bwmorph(~I,'thin',inf);
%figure,imshow(kl)
R(:,:)=kl(:,:);
%grid size
t1=5;
D=100;
I=1;
U1=t1;
J=1;
U2=t1;
E=1;
t2=D/t1;
%Z=1;
for i=1:t2
for j=1:t2
B(I:U1,J:U2)=R(I:U1,J:U2);
[x,y]=find(B==1);
CX=mean(x);
CY=mean(y);
CXXX(E)=CX;
CYYY(E)=CY;
CXX(i,j)=CX;
CYY(i,j)=CY;
T(I:U1,J:U2)=B(I:U1,J:U2);
J=J+t1;
U2=U2+t1;
E=E+1;
clear B x y
end
I=I+t1;
U1=U1+t1;
J=1;
U2=t1;
end
%plot and grid
figure,imshow(R)
hold on
M = size(R,1);
N = size(R,2);
a=t1;
b=t1;
for k = 1:a:M
x = [1 N];
y = [k k];
plot(x,y,'Color','white');
set(findobj('Tag','MyGrid'),'Visible','on')
end
for k = 1:b:N
x = [k k];
y = [1 M];
plot(x,y,'Color','white');
set(findobj('Tag','MyGrid'),'Visible','on')
end
plot(CYY,CXX,'c*')
this is my input image please try to run this code.
my input image
input image