Create Distance Transforn of 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<br /> //2:A bmp monochrome image(preferably 512-512)<br /> //make the image from mspaint or any other source</p> <p>import java.io.*;<br /> import javax.swing.*;<br /> import java.awt.*;<br /> import java.awt.event.*;<br /> public class newfndistrans extends JFrame{<br /> frame frm=null;<br /> File f;<br /> FileInputStream ff;<br /> Color cl;<br /> int count;<br /> int a[];</p> <p> int rnum,gnum;<br /> int xsize;<br /> int ysize;<br /> final int sample=5;<br /> String str=null;</p> <p>newfndistrans(String str)<br /> {<br /> super(str);<br /> frm=new frame();</p> <p> count=0;<br /> a=new int[8];<br /> rnum=0;gnum=0;<br /> }</p> <p> public void paint(Graphics g)<br /> {<br /> int x,y,i=0,j=0,temp;</p> <p> try{</p> <p> System.out.println(“Starting”);<br /> System.out.println(“filename=”+frm.getfilename());<br /> try{f=frm.getfilename();<br /> ff=new FileInputStream(f);<br /> }catch(Exception e){<br /> System.out.println(“error in reading file”);<br /> }<br /> ff.skip(18);<br /> i=ff.read();<br /> i=((ff.read()<<8)|i);<br /> i=((ff.read()<<16)|i);<br /> i=((ff.read()<<24)|i);<br /> xsize=i;<br /> System.out.println(“width=”+xsize);<br /> i=0;<br /> i=ff.read();<br /> i=((ff.read()<<8)|i);<br /> i=((ff.read()<<16)|i);<br /> i=((ff.read()<<24)|i);<br /> ysize=i;<br /> System.out.println(“Height=”+ysize);</p> <p> ff.skip(38);//62-(2+16+4+4=26)=36, actually total=62 Bytes header<br /> //note:make it 38 for nrectbit1.bmp and nrectbit2.bmp<br /> x=0;y=ysize;<br /> int pix[][],mat1[][];<br /> pix=new int[xsize][ysize];<br /> mat1=new int[xsize][ysize];<br /> System.out.println(“here”);<br /> while(true)<br /> {</p> <p> rnum=ff.read();<br /> //System.out.println(“rnum=”+rnum);<br /> if(rnum==-1)break;<br /> count=7;<br /> //image has 0 for black ,1 for white,but my convention is opposite<br /> while(rnum>0)<br /> {<br /> gnum=rnum%2;<br /> if(gnum==0)a[count]=1;<br /> else a[count]=0;<br /> count–;<br /> rnum=rnum/2;<br /> }<br /> while(count>=0)<br /> {a[count]=1;count–;<br /> }<br /> for(i=0;i<=7;i++)<br /> {if(a[i]==0)cl=new Color(255,255,255);<br /> else cl=new Color(0,0,0);<br /> pix[x][y-1]=a[i];<br /> mat1[x][y-1]=a[i];<br /> g.setColor(cl);<br /> g.drawRect(x,y,1,1);<br /> x++;<br /> if(x==xsize){x=0;y–;}<br /> }<br /> }//end while</p> <p>System.out.println(“File read successfully”);<br /> //sleep for 4 seconds(4000 msec)<br /> try{Thread.sleep(4000);<br /> }catch(Exception e){}<br /> //clear the region where the image was drawn,area near the boundaries<br /> are<br /> also cleaned<br /> for(j=0;j<=ysize+2;j++)<br /> for(i=0;i<=xsize+2;i++)<br /> g.clearRect(i,j,1,1);<br /> //cleaning done above</p> <p>//0 means white,1 means black<br /> //perform the distance transform<br /> for(j=0;j<ysize;j++)<br /> for(i=0;i<xsize;i++)<br /> {<br /> if(mat1[i][j]==0)continue;<br /> if((j==0)||(j==ysize-1)){mat1[i][j]=1;continue;}<br /> if((i==0)||(i==xsize-1)){mat1[i][j]=1;continue;}</p> <p>temp=findmin(mat1[i-1][j],mat1[i-1][j-1],mat1[i][j-1],mat1[i+1][j-1]);<br /> mat1[i][j]=temp+1;<br /> }</p> <p>//perform the distance transform from bottom<br /> for(j=ysize-1;j>=0;j–)<br /> for(i=xsize-1;i>=0;i–)<br /> {if(mat1[i][j]==0)continue;<br /> if((j==0)||(j==ysize-1)){mat1[i][j]=1;continue;}<br /> if((i==0)||(i==xsize-1)){mat1[i][j]=1;continue;}</p> <p>temp=findmin(mat1[i-1][j+1],mat1[i][j+1],mat1[i+1][j+1],mat1[i+1][j]);<br /> if(temp>(mat1[i][j]-1))temp=mat1[i][j]-1;<br /> mat1[i][j]=temp+1;<br /> }</p> <p>int max=-9999,colornum,i1,j1,globmax=-9999;<br /> x=0;y=0;<br /> for(j=0;j<ysize-(ysize%sample);j+=sample)<br /> for(i=0;i<xsize-(xsize%sample);i+=sample)<br /> {<br /> max=-9999;<br /> for(j1=j;j1<j+sample;j1++)<br /> for(i1=i;i1<i+sample;i1++)<br /> if(max<mat1[i1][j1])<br /> {<br /> max=mat1[i1][j1];<br /> //xcord=i1;ycord=j1;<br /> }<br /> //out of both above for loops<br /> if(globmax<max)globmax=max;</p> <p> if(max!=0)<br /> {<br /> System.out.println(“max=”+max);<br /> for(j1=j;j1<j+sample;j1++)<br /> for(i1=i;i1<i+sample;i1++)<br /> mat1[i1][j1]=max;<br /> }</p> <p> }<br /> System.out.println(“globmax=”+globmax);<br /> for(j=0;j<ysize;j++)<br /> for(i=0;i<xsize;i++)<br /> {colornum=(mat1[i][j]*255)/globmax;//contrast enhancement<br /> colornum=255-colornum;<br /> cl=new Color(colornum,colornum,colornum);<br /> g.setColor(cl);<br /> g.drawRect(i,j,1,1);<br /> }<br /> ff.close();<br /> System.out.println(“program ends”);<br /> }//end try block<br /> catch(Exception e)<br /> {System.out.println(“Error”+e.getMessage());<br /> }</p> <p> }<br /> int findmin(int num1,int num2,int num3,int num4)<br /> {<br /> int min=4000;<br /> if(min>num1)min=num1;<br /> if(min>num2)min=num2;<br /> if(min>num3)min=num3;<br /> if(min>num4)min=num4;<br /> return(min);<br /> }</p> <p> public static void main(String args[])<br /> {</p> <p> JFrame frm=new newfndistrans(“Distance Transform”);<br /> frm.setSize(700,700);<br /> frm.setVisible(true);</p> <p> }//end main()</p> <p>}// end class fndistrans<br /> class frame extends JFrame{<br /> JButton but;<br /> JFileChooser fch;<br /> String filename;<br /> File file=null;<br /> //Container con;<br /> boolean temp;<br /> frame()<br /> { super(“FileReading”);<br /> setSize(700,500);<br /> setLayout(new FlowLayout());</p> <p> temp=true;<br /> but=new JButton(“Open the binary file”);<br /> add(but);<br /> fch=new JFileChooser();<br /> but.addMouseListener(new MouseAdapter()<br /> { public void mousePressed(MouseEvent me)<br /> {<br /> int retval=fch.showOpenDialog(but);<br /> if(retval==JFileChooser.APPROVE_OPTION)<br /> {<br /> file=fch.getSelectedFile();<br /> filename=file.getName();<br /> System.out.println(“1filename=”+filename);<br /> temp=false;<br /> }</p> <p> }</p> <p> });<br /> setVisible(true);<br /> while(temp);<br /> }//end constructor<br /> File getfilename()<br /> {System.out.println(“filename=”+filename);<br /> return file;<br /> }</p> <p>}<br />