Zhang-Suen thinning algorithm: Difference between revisions
→{{header|C}}
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# ####
</pre>
=={{header|C}}==
Input and out images written from and to files. Format of input file is :
<Rows> <Columns>
<Blank pixel character> <Image Pixel character>
<Image of specified rows and columns made up of the two pixel types specified in the second line.>
The images before and after thinning are also printed on the console.
<lang C>
/*Abhishek Ghosh, 24th September 2017*/
#include<stdlib.h>
#include<stdio.h>
char** imageMatrix;
char blankPixel,imagePixel;
typedef struct{
int row,col;
}pixel;
int getBlackNeighbours(int row,int col){
int i,j,sum = 0;
for(i=-1;i<=1;i++){
for(j=-1;j<=1;j++){
if(i!=0 && j!=0)
sum+= (imageMatrix[row+i][col+i]==imagePixel);
}
}
return sum;
}
int getBWTransitions(int row,int col){
return ((imageMatrix[row-1][col]==blankPixel && imageMatrix[row-1][col+1]==imagePixel)
+(imageMatrix[row-1][col+1]==blankPixel && imageMatrix[row][col+1]==imagePixel)
+(imageMatrix[row][col+1]==blankPixel && imageMatrix[row+1][col+1]==imagePixel)
+(imageMatrix[row+1][col+1]==blankPixel && imageMatrix[row+1][col]==imagePixel)
+(imageMatrix[row+1][col]==blankPixel && imageMatrix[row+1][col-1]==imagePixel)
+(imageMatrix[row+1][col-1]==blankPixel && imageMatrix[row][col-1]==imagePixel)
+(imageMatrix[row][col-1]==blankPixel && imageMatrix[row-1][col-1]==imagePixel)
+(imageMatrix[row-1][col-1]==blankPixel && imageMatrix[row-1][col]==imagePixel));
}
int zhangSuenTest1(int row,int col){
int neighbours = getBlackNeighbours(row,col);
return ((neighbours>=2 && neighbours<=6)
&& (getBWTransitions(row,col)==1)
&& (imageMatrix[row-1][col]==blankPixel||imageMatrix[row][col+1]==blankPixel||imageMatrix[row+1][col]==blankPixel)
&& (imageMatrix[row][col+1]==blankPixel||imageMatrix[row+1][col]==blankPixel||imageMatrix[row][col-1]==blankPixel));
}
int zhangSuenTest2(int row,int col){
int neighbours = getBlackNeighbours(row,col);
return ((neighbours>=2 && neighbours<=6)
&& (getBWTransitions(row,col)==1)
&& (imageMatrix[row-1][col]==blankPixel||imageMatrix[row][col+1]==blankPixel||imageMatrix[row][col-1]==blankPixel)
&& (imageMatrix[row-1][col]==blankPixel||imageMatrix[row+1][col]==blankPixel||imageMatrix[row][col+1]==blankPixel));
}
void zhangSuen(char* inputFile, char* outputFile){
int startRow = 1,startCol = 1,endRow,endCol,i,j,count,rows,cols,processed;
pixel* markers;
FILE* inputP = fopen(inputFile,"r");
fscanf(inputP,"%d%d",&rows,&cols);
fscanf(inputP,"%d%d",&blankPixel,&imagePixel);
blankPixel<=9?blankPixel+='0':blankPixel;
imagePixel<=9?imagePixel+='0':imagePixel;
printf("\nPrinting original image :\n");
imageMatrix = (char**)malloc(rows*sizeof(char*));
for(i=0;i<rows;i++){
imageMatrix[i] = (char*)malloc((cols+1)*sizeof(char));
fscanf(inputP,"%s\n",imageMatrix[i]);
printf("\n%s",imageMatrix[i]);
}
//fclose(inputP);
endRow = rows-2;
endCol = cols-2;
do{
markers = (pixel*)malloc((endRow-startRow+1)*(endCol-startCol+1)*sizeof(pixel));
count = 0;
for(i=startRow;i<=endRow;i++){
for(j=startCol;j<=endCol;j++){
if(imageMatrix[i][j]==imagePixel && zhangSuenTest1(i,j)==1){
markers[count].row = i;
markers[count].col = j;
count++;
}
}
}
processed = (count>0);
for(i=0;i<count;i++){
imageMatrix[markers[i].row][markers[i].col] = blankPixel;
}
free(markers);
markers = (pixel*)malloc((endRow-startRow+1)*(endCol-startCol+1)*sizeof(pixel));
count = 0;
for(i=startRow;i<=endRow;i++){
for(j=startCol;j<=endCol;j++){
if(imageMatrix[i][j]==imagePixel && zhangSuenTest2(i,j)==1){
markers[count].row = i;
markers[count].col = j;
count++;
}
}
}
if(processed==0)
processed = (count>0);
for(i=0;i<count;i++){
imageMatrix[markers[i].row][markers[i].col] = blankPixel;
}
free(markers);
}while(processed==1);
FILE* outputP = fopen(outputFile,"w");
printf("\n\n\nPrinting image after applying Zhang Suen Thinning Algorithm : \n\n\n");
for(i=0;i<rows;i++){
for(j=0;j<cols;j++){
printf("%c",imageMatrix[i][j]);
fprintf(outputP,"%c",imageMatrix[i][j]);
}
printf("\n");
fprintf(outputP,"\n");
}
fclose(outputP);
printf("\nImage also written to : %s",outputFile);
}
int main()
{
char inputFile[100],outputFile[100];
printf("Enter full path of input image file : ");
scanf("%s",inputFile);
printf("Enter full path of output image file : ");
scanf("%s",outputFile);
zhangSuen(inputFile,outputFile);
return 0;
}
</lang>
Contents of input file : zhImage.txt
<pre>
10 32
0 1
00000000000000000000000000000000
01111111110000000111111110000000
01110001111000001111001111000000
01110000111000001110000111000000
01110001111000001110000000000000
01111111110000001110000000000000
01110111100000001110000111000000
01110011110011101111001111011100
01110001111011100111111110011100
00000000000000000000000000000000
</pre>
Console interaction :
<pre>
Enter full path of input image file : zhImage.txt
Enter full path of output image file : out.txt
Printing original image :
00000000000000000000000000000000
01111111110000000111111110000000
01110001111000001111001111000000
01110000111000001110000111000000
01110001111000001110000000000000
01111111110000001110000000000000
01110111100000001110000111000000
01110011110011101111001111011100
01110001111011100111111110011100
00000000000000000000000000000000
Printing image after applying Zhang Suen Thinning Algorithm :
00000000000000000000000000000000
00111111100000000011111100000000
00100000100000000110000000000000
01000000100000000100000000000000
01000000100000001000000000000000
01111111100000001000000000000000
01000001000000000100000011000000
01000001000001100110000110001100
01000000000010000001111000010000
00000000000000000000000000000000
Image also written to : out.txt
</pre>
Contents of out.txt :
<pre>
00000000000000000000000000000000
00111111100000000011111100000000
00100000100000000110000000000000
01000000100000000100000000000000
01000000100000001000000000000000
01111111100000001000000000000000
01000001000000000100000011000000
01000001000001100110000110001100
01000000000010000001111000010000
00000000000000000000000000000000
</pre>
=={{header|D}}==
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