http://hi.baidu.com/conglingks/blog/item/1ee6aade65d2015dcdbf1a22.html
細化算法的分類：
依據是否使用迭代運算可以分爲兩類：第一類是非迭代算法，一次即產生骨架，如基於距離變換的方法。遊程長度編碼細化等。第二類是迭代算法，即重複刪除圖像 邊緣滿足一定條件的像素，最終得到單像素寬帶骨架。迭代方法依據其檢查像素的方法又可以再分成串行算法和並行算法，在串行算法中，是否刪除像素在每次迭代 的執行中是固定順序的，它不僅取決於前次迭代的結果，也取決於本次迭代中已處理過像素點分佈情況，而在並行算法中，像素點刪除與否與像素值圖像中的順序無 關，僅取決於前次迭代的結果。在經典細化算法發展的同時，起源於圖像集合運算的形態學細化算法也得到了快速的發展。
Hilditch、Pavlidis、Rosenfeld細化算法：這類算法則是在程序中直接運算，根據運算結果來判定是否可以刪除點的算法，差別在於不同算法的判定條件不同。
其中Hilditch算法使用於二值圖像，比較普通，是一般的算法； Pavlidis算法通過並行和串行混合處理來實現，用位運算進行特定模式的匹配，所得的骨架是8連接的，使用於0－1二值圖像 ；Rosenfeld算法是一種並行細化算法，所得的骨架形態是8－連接的，使用於0－1二值圖像 。 後兩種算法的效果要更好一些，但是處理某些圖像時效果一般，第一種算法使用性強些。
索引表細化算法：經過預處理後得到待細化的圖像是0、1二值圖像。像素值爲1的是需要細化的部分，像素值爲0的是背景區域。基於索引表的算法就是依據一定 的判斷依據，所做出的一張表，然後根據魔鬼要細化的點的八個鄰域的情況查詢，若表中元素是1，若表中元素是1，則刪除該點（改爲背景），若是0則保留。因 爲一個像素的8個鄰域共有256中可能情況，因此，索引表的大小一般爲256。
圖象細化算法代碼：
下面是我在網上搜索到的一些細化算法的源碼，只是爲了自己學習方便，可能有錯誤。
【來 源】：http ://blog.csdn.net/byxdaz/archive/2006/02/27/610835.aspx
/////////////////////////////////////////////////////////////////////////
//Hilditch細化算法
//功能：對圖象進行細化
//參數：image：代表圖象的一維數組
// lx：圖象寬度
// ly：圖象高度
// 無返回值
void ThinnerHilditch(void *image, unsigned long lx, unsigned long ly)
{
char *f, *g;
char n[10];
unsigned int counter;
short k, shori, xx, nrn;
unsigned long i, j;
long kk, kk11, kk12, kk13, kk21, kk22, kk23, kk31, kk32, kk33, size;
size = (long)lx * (long)ly;
g = (char *)malloc(size);
if(g == NULL)
{
printf("error in allocating memory!/n");
return;
}
f = (char *)image;
for(i=0; i<lx; i++)
{
for(j=0; j<ly; j++)
{
kk="i"*ly+j;
if(f[kk]!=0)
{
f[kk]=1;
g[kk]=f[kk];
}
}
}
counter = 1;
do
{
printf("%4d*",counter);
counter++;
shori = 0;
for(i=0; i<lx; i++)
{
for(j=0; j<ly; j++)
{
kk = i*ly+j;
if(f[kk]<0)
f[kk] = 0;
g[kk]= f[kk];
}
}
for(i=1; i<lx-1; i++)
{
for(j=1; j<ly-1; j++)
{
kk="i"*ly+j;
if(f[kk]!=1)
continue;
kk11 = (i-1)*ly+j-1;
kk12 = kk11 + 1;
kk13 = kk12 + 1;
kk21 = i*ly+j-1;
kk22 = kk21 + 1;
kk23 = kk22 + 1;
kk31 = (i+1)*ly+j-1;
kk32 = kk31 + 1;
kk33 = kk32 + 1;
if((g[kk12]&&g[kk21]&&g[kk23]&&g[kk32])!=0)
continue;
nrn = g[kk11] + g[kk12] + g[kk13] + g[kk21] + g[kk23] +
g[kk31] + g[kk32] + g[kk33];
if(nrn <= 1)
{
f[kk22] = 2;
continue;
}
n[4] = f[kk11];
n[3] = f[kk12];
n[2] = f[kk13];
n[5] = f[kk21];
n[1] = f[kk23];
n[6] = f[kk31];
n[7] = f[kk32];
n[8] = f[kk33];
n[9] = n[1];
xx = 0;
for(k=1; k<8; k="k"+2)
{
if((!n[k])&&(n[k+1]||n[k+2]))
xx++;
}
if(xx!=1)
{
f[kk22] = 2;
continue;
}
if(f[kk12] == -1)
{
f[kk12] = 0;
n[3] = 0;
xx = 0;
for(k=1; k<8; k="k"+2)
{
if((!n[k])&&(n[k+1]||n[k+2]))
xx++;
}
if(xx != 1)
{
f[kk12] = -1;
continue;
}
f[kk12] = -1;
n[3] = -1;
}
if(f[kk21]!=-1)
{
f[kk22] = -1;
shori = 1;
continue;
}
f[kk21] = 0;
n[5] = 0;
xx = 0;
for(k=1; k<8; k="k"+2)
{
if((!n[k])&&(n[k+1]||n[k+2]))
{
xx++;
}
}
if(xx == 1)
{
f[kk21] = -1;
f[kk22] = -1;
shori =1;
}
else
f[kk21] = -1;
}
}
}while(shori);
free(g);
}
/////////////////////////////////////////////////////////////////////////
//Pavlidis細化算法
//功能：對圖象進行細化
//參數：image：代表圖象的一維數組
// lx：圖象寬度
// ly：圖象高度
// 無返回值
void ThinnerPavlidis(void *image, unsigned long lx, unsigned long ly)
{
char erase, n[8];
char *f;
unsigned char bdr1,bdr2,bdr4,bdr5;
short c,k,b;
unsigned long i,j;
long kk,kk1,kk2,kk3;
f = (char*)image;
for(i=1; i<lx-1; i++)
{
for(j=1; j<ly-1; j++)
{
kk = i*ly + j;
if(f[kk])
f[kk] = 1;
}
}
for(i=0, kk1=0, kk2=ly-1; i<lx; i++, kk1+=ly, kk2+=ly)
{
f[kk1]=0;
f[kk2]=0;
}
for(j=0, kk=(lx-1)*ly; j<ly; j++,kk++)
{
f[j]=0;
f[kk]=0;
}
c="5";
erase =1;
while(erase)
{
c++;
for(i=1; i<lx-1; i++)
{
for(j=1; j<ly-1; j++)
{
kk="i"*ly+j;
if(f[kk]!=1)
continue;
kk1 = kk-ly -1;
kk2 = kk1 + 1;
kk3 = kk2 + 1;
n[3] = f[kk1];
n[2] = f[kk2];
n[1] = f[kk3];
kk1 = kk - 1;
kk3 = kk + 1;
n[4] = f[kk1];
n[0] = f[kk3];
kk1 = kk + ly -1;
kk2 = kk1 + 1;
kk3 = kk2 + 1;
n[5] = f[kk1];
n[6] = f[kk2];
n[7] = f[kk3];
bdr1 =0;
for(k=0; k<8; k++)
{
if(n[k]>=1)
bdr1|=0x80>>k;
}
if((bdr1&0252)== 0252)
continue;
f[kk] = 2;
b="0";
for(k=0; k<=7; k++)
{
b+=bdr1&(0x80>>k);
}
if(b<=1)
f[kk]=3;
if((bdr1&0160)!=0&&(bdr1&07)!=0&&(bdr1&0210)==0)
f[kk]=3;
else if((bdr1&&0301)!=0&&(bdr1&034)!=0&&(bdr1&042)==0)
f[kk]=3;
else if((bdr1&0202)==0 && (bdr1&01)!=0)
f[kk]=3;
else if((bdr1&0240)==0 && (bdr1&0100)!=0)
f[kk]=3;
else if((bdr1&050)==0 && (bdr1&020)!=0)
f[kk]=3;
else if((bdr1&012)==0 && (bdr1&04)!=0)
f[kk]=3;
}
}
for(i=1; i<lx-1; i++)
{
for(j=1; j<ly-1; j++)
{
kk = i*ly + j;
if(!f[kk])
continue;
kk1 = kk - ly -1;
kk2 = kk1 + 1;
kk3 = kk2 + 1;
n[3] = f[kk1];
n[2] = f[kk2];
n[1] = f[kk3];
kk1 = kk - 1;
kk2 = kk + 1;
n[4] = f[kk1];
n[0] = f[kk3];
kk1 = kk + ly -1;
kk2 = kk1 + 1;
kk3 = kk2 + 1;
n[5] = f[kk1];
n[6] = f[kk2];
n[7] = f[kk3];
bdr1 = bdr2 =0;
for(k=0; k<=7; k++)
{
if(n[k]>=1)
bdr1|=0x80>>k;
if(n[k]>=2)
bdr2|=0x80>>k;
}
if(bdr1==bdr2)
{
f[kk] = 4;
continue;
}
if(f[kk]!=2)
continue;
if((bdr2&0200)!=0 && (bdr1&010)==0 &&
((bdr1&0100)!=0 &&(bdr1&001)!=0 ||
((bdr1&0100)!=0 ||(bdr1 & 001)!=0) &&
(bdr1&060)!=0 &&(bdr1&06)!=0))
{
f[kk] = 4;
}
else if((bdr2&040)!=0 && (bdr1&02)==0 &&
((bdr1&020)!=0 && (bdr1&0100)!=0 ||
((bdr1&020)!=0 || (bdr1&0100)!=0) &&
(bdr1&014)!=0 && (bdr1&0201)!=0))
{
f[kk] = 4;
}
else if((bdr2&010)!=0 && (bdr1&0200)==0 &&
((bdr1&04)!=0 && (bdr1&020)!=0 ||
((bdr1&04)!=0 || (bdr1&020)!=0) &&
(bdr1&03)!=0 && (bdr1&0140)!=0))
{
f[kk] = 4;
}
else if((bdr2&02)!=0 && (bdr1&040)==0 &&
((bdr1&01)!=0 && (bdr1&04)!=0 ||
((bdr1&01)!=0 || (bdr1&04)!=0) &&
(bdr1&0300)!=0 && (bdr1&030)!=0))
{
f[kk] = 4;
}
}
}
for(i=1; i<lx-1; i++)
{
for(j=1; j<ly-1; j++)
{
kk = i*ly + j;
if(f[kk]!=2)
continue;
kk1 = kk - ly -1;
kk2 = kk1 + 1;
kk3 = kk2 + 1;
n[3] = f[kk1];
n[2] = f[kk2];
n[1] = f[kk3];
kk1 = kk - 1;
kk2 = kk + 1;
n[4] = f[kk1];
n[0] = f[kk3];
kk1 = kk + ly -1;
kk2 = kk1 + 1;
kk3 = kk2 + 1;
n[5] = f[kk1];
n[6] = f[kk2];
n[7] = f[kk3];
bdr4 = bdr5 =0;
for(k=0; k<=7; k++)
{
if(n[k]>=4)
bdr4|=0x80>>k;
if(n[k]>=5)
bdr5|=0x80>>k;
}
if((bdr4&010) == 0)
{
f[kk] = 5;
continue;
}
if((bdr4&040) == 0 && bdr5 ==0)
{
f[kk] = 5;
continue;
}
if(f[kk]==3||f[kk]==4)
f[kk] = c;
}
}
erase = 0;
for(i=1; i<lx-1; i++)
{
for(j=1; j<ly-1; j++)
{
kk = i*ly +j;
if(f[kk]==2||f[kk] == 5)
{
erase = 1;
f[kk] = 0;
}
}
}
}
}
/////////////////////////////////////////////////////////////////////////
//Rosenfeld細化算法
//功能：對圖象進行細化
//參數：image：代表圖象的一維數組
// lx：圖象寬度
// ly：圖象高度
// 無返回值
void ThinnerRosenfeld(void *image, unsigned long lx, unsigned long ly)
{
char *f, *g;
char n[10];
char a[5] = {0, -1, 1, 0, 0};
char b[5] = {0, 0, 0, 1, -1};
char nrnd, cond, n48, n26, n24, n46, n68, n82, n123, n345, n567, n781;
short k, shori;
unsigned long i, j;
long ii, jj, kk, kk1, kk2, kk3, size;
size = (long)lx * (long)ly;
g = (char *)malloc(size);
if(g==NULL)
{
printf("error in alocating mmeory!/n");
return;
}
f = (char *)image;
for(kk=0l; kk<size; kk++)
{
g[kk] = f[kk];
}
do
{
shori = 0;
for(k=1; k<=4; k++)
{
for(i=1; i<lx-1; i++)
{
ii = i + a[k];
for(j=1; j<ly-1; j++)
{
kk = i*ly + j;
if(!f[kk])
continue;
jj = j + b[k];
kk1 = ii*ly + jj;
if(f[kk1])
continue;
kk1 = kk - ly -1;
kk2 = kk1 + 1;
kk3 = kk2 + 1;
n[3] = f[kk1];
n[2] = f[kk2];
n[1] = f[kk3];
kk1 = kk - 1;
kk3 = kk + 1;
n[4] = f[kk1];
n[8] = f[kk3];
kk1 = kk + ly - 1;
kk2 = kk1 + 1;
kk3 = kk2 + 1;
n[5] = f[kk1];
n[6] = f[kk2];
n[7] = f[kk3];
nrnd = n[1] + n[2] + n[3] + n[4]
+n[5] + n[6] + n[7] + n[8];
if(nrnd<=1)
continue;
cond = 0;
n48 = n[4] + n[8];
n26 = n[2] + n[6];
n24 = n[2] + n[4];
n46 = n[4] + n[6];
n68 = n[6] + n[8];
n82 = n[8] + n[2];
n123 = n[1] + n[2] + n[3];
n345 = n[3] + n[4] + n[5];
n567 = n[5] + n[6] + n[7];
n781 = n[7] + n[8] + n[1];
if(n[2]==1 && n48==0 && n567>0)
{
if(!cond)
continue;
g[kk] = 0;
shori = 1;
continue;
}
if(n[6]==1 && n48==0 && n123>0)
{
if(!cond)
continue;
g[kk] = 0;
shori = 1;
continue;
}
if(n[8]==1 && n26==0 && n345>0)
{
if(!cond)
continue;
g[kk] = 0;
shori = 1;
continue;
}
if(n[4]==1 && n26==0 && n781>0)
{
if(!cond)
continue;
g[kk] = 0;
shori = 1;
continue;
}
if(n[5]==1 && n46==0)
{
if(!cond)
continue;
g[kk] = 0;
shori = 1;
continue;
}
if(n[7]==1 && n68==0)
{
if(!cond)
continue;
g[kk] = 0;
shori = 1;
continue;
}
if(n[1]==1 && n82==0)
{
if(!cond)
continue;
g[kk] = 0;
shori = 1;
continue;
}
if(n[3]==1 && n24==0)
{
if(!cond)
continue;
g[kk] = 0;
shori = 1;
continue;
}
cond = 1;
if(!cond)
continue;
g[kk] = 0;
shori = 1;
}
}
for(i=0; i<lx; i++)
{
for(j=0; j<ly; j++)
{
kk = i*ly + j;
f[kk] = g[kk];
}
}
}
}while(shori);
free(g);
}
/////////////////////////////////////////////////////////////////////////
//基於索引表的細化細化算法
//功能：對圖象進行細化
//參數：lpDIBBits：代表圖象的一維數組
// lWidth：圖象高度
// lHeight：圖象寬度
// 無返回值
BOOL WINAPI ThiningDIBSkeleton (LPSTR lpDIBBits, LONG lWidth, LONG lHeight)
{
//循環變量
long i;
long j;
long lLength;
unsigned char deletemark[256] = {
0,0,0,0,0,0,0,1, 0,0,1,1,0,0,1,1,
0,0,0,0,0,0,0,0, 0,0,1,1,1,0,1,1,
0,0,0,0,0,0,0,0, 1,0,0,0,1,0,1,1,
0,0,0,0,0,0,0,0, 1,0,1,1,1,0,1,1,
0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0, 1,0,0,0,1,0,1,1,
1,0,0,0,0,0,0,0, 1,0,1,1,1,0,1,1,
0,0,1,1,0,0,1,1, 0,0,0,1,0,0,1,1,
0,0,0,0,0,0,0,0, 0,0,0,1,0,0,1,1,
1,1,0,1,0,0,0,1, 0,0,0,0,0,0,0,0,
1,1,0,1,0,0,0,1, 1,1,0,0,1,0,0,0,
0,1,1,1,0,0,1,1, 0,0,0,1,0,0,1,1,
0,0,0,0,0,0,0,0, 0,0,0,0,0,1,1,1,
1,1,1,1,0,0,1,1, 1,1,0,0,1,1,0,0,
1,1,1,1,0,0,1,1, 1,1,0,0,1,1,0,0
};//索引表
unsigned char p0, p1, p2, p3, p4, p5, p6, p7;
unsigned char *pmid, *pmidtemp;
unsigned char sum;
int changed;
bool bStart = true;
lLength = lWidth * lHeight;
unsigned char *pTemp = (unsigned char *)malloc(sizeof(unsigned char) * lWidth * lHeight);
// P0 P1 P2
// P7 P3
// P6 P5 P4
while(bStart)
{
bStart = false;
changed = 0;
//首先求邊緣點(並行)
pmid = (unsigned char *)lpDIBBits + lWidth + 1;
memset(pTemp, (BYTE) 0, lLength);
pmidtemp = (unsigned char *)pTemp + lWidth + 1;
for(i = 1; i < lHeight -1; i++)
{
for(j = 1; j < lWidth - 1; j++)
{
if( *pmid == 0)
{
pmid++;
pmidtemp++;
continue;
}
p3 = *(pmid + 1);
p2 = *(pmid + 1 - lWidth);
p1 = *(pmid - lWidth);
p0 = *(pmid - lWidth -1);
p7 = *(pmid - 1);
p6 = *(pmid + lWidth - 1);
p5 = *(pmid + lWidth);
p4 = *(pmid + lWidth + 1);
sum = p0 & p1 & p2 & p3 & p4 & p5 & p6 & p7;
if(sum == 0)
{
*pmidtemp = 1;
}
pmid++;
pmidtemp++;
}
pmid++;
pmid++;
pmidtemp++;
pmidtemp++;
}
//現在開始串行刪除
pmid = (unsigned char *)lpDIBBits + lWidth + 1;
pmidtemp = (unsigned char *)pTemp + lWidth + 1;
for(i = 1; i < lHeight -1; i++)
{
for(j = 1; j < lWidth - 1; j++)
{
if( *pmidtemp == 0)
{
pmid++;
pmidtemp++;
continue;
}
p3 = *(pmid + 1);
p2 = *(pmid + 1 - lWidth);
p1 = *(pmid - lWidth);
p0 = *(pmid - lWidth -1);
p7 = *(pmid - 1);
p6 = *(pmid + lWidth - 1);
p5 = *(pmid + lWidth);
p4 = *(pmid + lWidth + 1);
p1 *= 2;
p2 *= 4;
p3 *= 8;
p4 *= 16;
p5 *= 32;
p6 *= 64;
p7 *= 128;
sum = p0 | p1 | p2 | p3 | p4 | p5 | p6 | p7;
if(deletemark[sum] == 1)
{
*pmid = 0;
bStart = true;
}
pmid++;
pmidtemp++;
}
pmid++;
pmid++;
pmidtemp++;
pmidtemp++;
}
}
return true;
}