8-邻域边界跟踪算法

C++

利用点的八邻域信息，选择下一个点作为边界点，这个算法需要选择一个开始点，可以选择图像上是目标点，在最上，最左的点。然后查看它的八邻域的点，从右下方45°的位置开始寻找，如果是目标点，将沿顺时针90°作为下一次寻找的方向，如果不是，则逆时针45°继续寻找，一旦找到重复上面的过程。

void VessDibTrack(HDIB hdib,vector& pt) //八邻域

{

unsigned char *lpSrc;

LPSTR lpDIB = (LPSTR) ::GlobalLock((HGLOBAL)hdib);

int cxDIB = (int) ::DIBWidth(lpDIB); // Size of DIB - x

int cyDIB = (int) ::DIBHeight(lpDIB); // Size of DIB - y

LPSTR lpDIBBits=::FindDIBBits (lpDIB);

long lLineBytes = WIDTHBYTES(cxDIB * 8); //计算图像每行的字节数

//寻找开始点，最右，最下

//先行，后列

int i,j;

POINT startPt,currPt;

for (i = 0;i

{

for (j = 0;j

{

lpSrc = (unsigned char*)lpDIBBits + lLineBytes * (cyDIB -1 - i) + j;if (*lpSrc==0) //是黑点

startPt.x = i;

startPt.y = j;

//停止条件

i = cyDIB;

j = cxDIB;

}

}

}

//设置方向数组

//intdirection[8][2]={{-1,-1},{0,-1},{1,-1},{1,0},{1,1},{0,1},{-1,1},{-1,0}};int direction[8][2] = {{-1,1},{0,1},{1,1},{1,0},{1,-1},{0,-1},{-1,-1},{-1,0}};int startDirect ;

BOOL FindStartPoint = FALSE;

BOOL FindPoint = FALSE;

//开始跟踪

currPt.x = startPt.x;

currPt.y = startPt.y;

POINT NextPt ;

int NextPtValue;

startDirect = 0;

int cnt= 0;

while(!FindStartPoint&&cnt<100000)

FindPoint = FALSE;

pt.push_back(currPt);

while(!FindPoint)

{

//沿预定方向扫描，寻找下一个点

NextPt.x = currPt.x + direction[startDirect][1];

NextPt.y = currPt.y + direction[startDirect][0];

lpSrc = (unsigned char*)lpDIBBits + lLineBytes * (cyDIB -1 - NextPt.x) +NextPt.y; //NextPtValue = GetPiexValue(hdib,NextPt.x,NextPt.y);

NextPtValue = * lpSrc;

if (NextPtValue ==

0&&NextPt.x>=0&&NextPt.x=0&&NextPt.y

{

FindPoint = TRUE;

currPt.x = NextPt.x;

currPt.y = NextPt.y;

if (currPt.x == startPt.x&&currPt.y == startPt.y)

{

FindStartPoint = TRUE;

}

startDirect = startDirect-2;

if(startDirect<0) startDirect = startDirect+8; }

else

{

startDirect = startDirect+1;

if (startDirect>=8) startDirect = startDirect-8; }

}

cnt ++;

}

::GlobalUnlock((HGLOBAL) hdib);

}