// Identifies different connected components in the input image and modifies the input image such that,
// it deletes any components with size lesser than the threshold size
// Also returns ncc (number of connected components) and ntcc (number of connected components with size greater than threshold)
void thr_Connected_Component( char *im, int thr, int nx, int ny, int nz, int *ncc, int *ntcc) {
int *labeled_im;
int N,*CClabel,*CCsize;
int nv;
nv= nx*ny*nz;
labeled_im=(int *)calloc(nv,sizeof(int)); //Allocate memory for the labeled connected component image
if(thr <= 0)
{
printf("\n Threshold has to be greater than zero\n");
exit(0);
}
// creates a labeled image 'labeled_im', such that all voxels in the binary image which are zero
// will remain zero in labeled image and all voxels which are non zero will have a distinct label based on pixel connectivity
// N: Number of cluster
// CClable: Lable number of each cluster
// CCsize: Size of each cluster
Connected_Components(im,nx,ny,nz,labeled_im,&N,&CClabel,&CCsize);
//Find the connected components with size greater than threshold
for(int i=0; i<nv; i++) im[i]=0;
*ntcc = 0;
for(int i=0; i<N; i++)
if(CCsize[i]>=thr) ++*ntcc;
int k=0;
for(int i=0; i<nv; i++)
{
if(labeled_im[i])
{
if(labeled_im[i]==CClabel[k] && CCsize[k]>=thr) im[i]=1;
else if(labeled_im[i]<CClabel[N/2])
for(int j=0; j<N/2; j++)
{
if (labeled_im[i]==CClabel[j] && CCsize[j]>=thr)
{
im[i]=1; k=j;
break;
}
}
else
for(int j=N/2; j<N; j++)
{
if (labeled_im[i]==CClabel[j] && CCsize[j]>=thr)
{
im[i]=1; k=j;
break;
}
}
}
}
*ncc = N;
free(labeled_im); free(CClabel); free(CCsize);
}
// Identifies connected components in input image and stores the location of voxels in each connected component in array L.
// It also computes array S, where S[i] points to the location in L from where the index of voxels in ith connected component are stored
// Also returns ncc (number of connected components)
void Connected_Component_location(char *im, int nx, int ny, int nz, int *ncc, int **S, int **L, int **CCsize)
{
int *labeled_im;
int *CClabel;
int nv,np;
int N;
int nbv; // Number of non-zero voxels in input image
char *imtemp;
nv = nx*ny*nz;
np = nx*ny;
labeled_im=(int *)calloc(nv,sizeof(int)); // Allocate memory for the labeled connected component image
// creates a labeled image 'labeled_im', such that all voxels in the binary image which are zero
// will remain zero in labeled image and all voxels which are non zero will have a distinct label based on pixel connectivity
// N: Number of cluster
// CClable: Lable number of each cluster
// CCsize: Size of each cluster
Connected_Components(im,nx,ny,nz,labeled_im,&N,&CClabel,CCsize);
nbv=0;
for(int i=0; i<N; i++) nbv += (*CCsize)[i];
(*L)=(int *)calloc(nbv,sizeof(int)); // Allocate memory to store the voxel index
(*S)=(int *)calloc(N,sizeof(int));
imtemp=(char *)calloc(nv,sizeof(char));
for(int i=0; i<nv; i++) imtemp[i]=im[i];
(*S)[0]=0;
for(int i=1; i<N; i++) (*S)[i] = (*S)[i-1] + (*CCsize)[i-1];
// Store the location of voxels in each connected component
int ii=0;
for(int i=0; i<N; i++)
{
for(int j=0; j<nv; j++)
{
if(imtemp[j])
{
if(CClabel[i]==labeled_im[j])
{
(*L)[ii++]=j;
imtemp[j]=0;
}
}
}
}
*ncc = N;
free(labeled_im); free(CClabel); free(imtemp);
}
int main(void) {
Build_Graph(Adj, N);
Print_Adjacency_Matrix(Adj, N);
Connected_Components();
Print_Disjoint_Sets();
if ( Same_Component(5, 7) )
printf("Yes\n");
else
printf("No\n");
system("pause");
return 0;
}
// Identifies different connected components in the input image and modifies the input image such that,
// all the components are removed from the image except for one component, which has the maximum size
// Also returns ncc (number of connected components) and maxsize (maximum component size)
void max_Connected_Component( char *im, int nx, int ny, int nz, int *ncc, int *maxsize)
{
int *labeled_im;
int N,L,*CClabel,*CCsize;
int nv;
nv=nx*ny*nz;
labeled_im=(int *)calloc(nv,sizeof(int)); // Allocate memory for the labeled connected component image
// creates a labeled image 'labeled_im', such that all voxels in the binary image which are zero
// will remain zero in labeled image and all voxels which are non zero will have a distinct label based on pixel connectivity
// N: Number of cluster
// CClable: Lable number of each cluster
// CCsize: Size of each cluster
Connected_Components(im,nx,ny,nz,labeled_im,&N,&CClabel,&CCsize);
*maxsize = 0;
// Find max cluster size
for(int i=0; i<N; i++)
if(CCsize[i] > *maxsize)
{
*maxsize = CCsize[i];
L = CClabel[i];
}
// Find the connected component with max size
for(int i=0; i<nv; i++)
if(im[i])
{
if(labeled_im[i] == L)
im[i] = 1;
else im[i] = 0;
}
*ncc = N;
free(labeled_im); free(CClabel); free(CCsize);
}
// Identifies different connected components in the input image and modifies the input image such that,
// it deletes any components with height lesser than the threshold height
// Also returns ncc (number of connected components) and ntcc (number of connected components with height greater than threshold)
void heightthr_Connected_Component(float *im, float thr, int nx, int ny, int nz, int *ncc, int *ntcc)
{
int *labeled_im;
char *imtemp;
int N,*CClabel,*CCsize;
float *CCheight;
int nv,np;
nv = nx*ny*nz;
np = nx*ny;
labeled_im=(int *)calloc(nv,sizeof(int)); // Allocate memory for the labeled connected component image
imtemp=(char *)calloc(nv,sizeof(char));
for(int i=0; i<nv; i++)
if(im[i]) imtemp[i]=1;
// creates a labeled image 'labeled_im', such that all voxels in the binary image which are zero
// will remain zero in labeled image and all voxels which are non zero will have a distinct label based on pixel connectivity
// N: Number of cluster
// CClable: Lable number of each cluster
// CCsize: Size of each cluster
Connected_Components(imtemp,nx,ny,nz,labeled_im,&N,&CClabel,&CCsize);
// Find the height of each connected component
CCheight = (float *)calloc(N,sizeof(float));
for(int i=0; i<N; i++)
CCheight[i]=0.0;
int k=0;
for(int i=0; i<nv; i++)
{
if(labeled_im[i])
{
if(labeled_im[i]==CClabel[k] && im[i]>CCheight[k])
CCheight[k]=im[i];
else if(labeled_im[i] < CClabel[N/2])
for(int j=0; j<N/2; j++)
{
if (labeled_im[i]==CClabel[j] && im[i]>CCheight[j])
{
CCheight[j]=im[i]; k=j;
break;
}
}
else
for(int j=N/2; j<N; j++)
{
if (labeled_im[i]==CClabel[j] && im[i]>CCheight[j])
{
CCheight[j]=im[i]; k=j;
break;
}
}
}
}
// Find the connected components with height greater than threshold
for(int i=0; i<nv; i++)
im[i]=0.0;
*ntcc = 0;
for(int i=0; i<N; i++)
if(CCheight[i]>=thr) ++*ntcc;
k=0;
for(int i=0; i<nv; i++)
{
if(labeled_im[i])
{
if(labeled_im[i]==CClabel[k] && CCheight[k]>=thr)
im[i]=1.0;
else if(labeled_im[i] < CClabel[N/2])
for(int j=0; j<N/2; j++)
{
if (labeled_im[i]==CClabel[j] && CCheight[j]>=thr)
{
im[i]=1.0; k=j;
break;
}
}
else
for(int j=N/2; j<N; j++)
{
if (labeled_im[i]==CClabel[j] && CCheight[j]>=thr)
{
im[i]=1.0; k=j;
break;
}
}
}
}
*ncc = N;
free(labeled_im); free(CClabel); free(CCsize); free(CCheight); free(imtemp);
}
