The Distance Transform of a Binary Image This is a image processing program which performs the distance transform of a binary image.Distance transfo

The Distance Transform of a Binary Image

This is a image processing program which performs the distance transform of a binary image.Distance transform is widely used for image thinning and finding skeleton of an image.

//1:newfndistrans.java
//2:A bmp monochrome image(preferably 512-512)
//make the image from mspaint or any other source


import java.io.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class newfndistrans extends JFrame{
frame frm=null;
File f;
FileInputStream ff;
Color cl;
int count;
int a[];

int rnum,gnum;
int xsize;
int ysize;
final int sample=5;
String str=null;

newfndistrans(String str)
{
super(str);
frm=new frame();


count=0;
a=new int[8];
rnum=0;gnum=0;
}

public void paint(Graphics g)
{
int x,y,i=0,j=0,temp;

try{

System.out.println("Starting");
System.out.println("filename="+frm.getfilename());
try{f=frm.getfilename();
ff=new FileInputStream(f);
}catch(Exception e){
System.out.println("error in reading file");
}
ff.skip(18);
i=ff.read();
i=((ff.read()<<8 i="((ff.read()<<16" i="((ff.read()<<24" xsize="i;" width="+xsize); i=0; i=ff.read(); i=((ff.read()<<8 )|i ); i=((ff.read()<<16 )|i ); i=((ff.read()<<24 )|i ); ysize=i; System.out.println(" height="+ysize); ff.skip(38);//62-(2+16+4+4=26)=36, actually total=62 Bytes header //note:make it 38 for nrectbit1.bmp and nrectbit2.bmp x=0;y=ysize; int pix[][],mat1[][]; pix=new int[xsize][ysize]; mat1=new int[xsize][ysize]; System.out.println(" rnum="ff.read();" rnum="" rnum="="-1)break;" count="7;">0)
{
gnum=rnum%2;
if(gnum==0)a[count]=1;
else a[count]=0;
count--;
rnum=rnum/2;
}
while(count>=0)
{a[count]=1;count--;
}
for(i=0;i<=7;i++) {if(a==0)cl=new Color(255,255,255);
else cl=new Color(0,0,0);
pix

• [y-1]=a;

mat1

• [y-1]=a;

g.setColor(cl);
g.drawRect(x,y,1,1);
x++;
if(x==xsize){x=0;y--;}
}
}//end while

System.out.println("File read successfully");
//sleep for 4 seconds(4000 msec)
try{Thread.sleep(4000);
}catch(Exception e){}
//clear the region where the image was drawn,area near the boundaries
are
also cleaned
for(j=0;j<=ysize+2;j++) for(i=0;i<=xsize+2;i++) g.clearRect(i,j,1,1); //cleaning done above //0 means white,1 means black //perform the distance transform for(j=0;j[j]==0)continue;
if((j==0)||(j==ysize-1)){mat1[j]=1;continue;}
if((i==0)||(i==xsize-1)){mat1[j]=1;continue;}


temp=findmin(mat1[i-1][j],mat1[i-1][j-1],mat1[j-1],mat1[i+1][j-1]);
mat1[j]=temp+1;
}



//perform the distance transform from bottom
for(j=ysize-1;j>=0;j--)
for(i=xsize-1;i>=0;i--)
{if(mat1[j]==0)continue;
if((j==0)||(j==ysize-1)){mat1[j]=1;continue;}
if((i==0)||(i==xsize-1)){mat1[j]=1;continue;}


temp=findmin(mat1[i-1][j+1],mat1[j+1],mat1[i+1][j+1],mat1[i+1][j]);
if(temp>(mat1[j]-1))temp=mat1[j]-1;
mat1[j]=temp+1;
}

int max=-9999,colornum,i1,j1,globmax=-9999;
x=0;y=0;
for(j=0;j[j]*255)/globmax;//contrast enhancement
colornum=255-colornum;
cl=new Color(colornum,colornum,colornum);
g.setColor(cl);
g.drawRect(i,j,1,1);
}
ff.close();
System.out.println(" program="" ends="">
}//end try block
catch(Exception e)
{System.out.println("Error"+e.getMessage());
}



}
int findmin(int num1,int num2,int num3,int num4)
{
int min=4000;
if(min>num1)min=num1;
if(min>num2)min=num2;
if(min>num3)min=num3;
if(min>num4)min=num4;
return(min);
}

public static void main(String args[])
{

JFrame frm=new newfndistrans("Distance Transform");
frm.setSize(700,700);
frm.setVisible(true);


}//end main()

}// end class fndistrans
class frame extends JFrame{
JButton but;
JFileChooser fch;
String filename;
File file=null;
//Container con;
boolean temp;
frame()
{ super("FileReading");
setSize(700,500);
setLayout(new FlowLayout());

temp=true;
but=new JButton("Open the binary file");
add(but);
fch=new JFileChooser();
but.addMouseListener(new MouseAdapter()
{ public void mousePressed(MouseEvent me)
{
int retval=fch.showOpenDialog(but);
if(retval==JFileChooser.APPROVE_OPTION)
{
file=fch.getSelectedFile();
filename=file.getName();
System.out.println("1filename="+filename);
temp=false;
}

}

});
setVisible(true);
while(temp);
}//end constructor
File getfilename()
{System.out.println("filename="+filename);
return file;
}

}