openCv学习笔记(五)-数学形态学2(灰度级膨胀和腐蚀及c语言实现)

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一 基本概念

     所谓的灰度级膨胀和腐蚀即将而知图像的二值形态学运算推广到灰度图像上。对于一幅图像的腐蚀(膨胀)运算定义为对每个像素赋值为某个领域内输入图像灰度级的最小(或最大值)。在二值变换中的结构元素只代表一个领域,而在灰度级变化中,结构元素是一个二元函数,它规定了希望的局部灰度级性质。在求的邻域内最大值(或最小值)的同时,将结构元素的值相加(相减)。

   以下的灰度级运算将从数学的角度描述。这里引进两个概念。即本影和顶面函数

  考虑一个n维欧式空间中的点集A(即一幅灰度图像)。并假定前(n-1)个坐标构成一个空间定义域(像素点坐标),而第n个坐标轴表示某点的函数值(对于灰度图像来说,n=3)。简单的说就是集合A为三维矩阵,其中点由坐标的三元表示,前两元表示像素的坐标,第三个元表示高度,即像素的亮度。

   1.1集合A的顶面:为定义在(n-1)维底面上的函数,对于每个(n-1)元祖来书,顶面就是A最后一个坐标的最高值。(个人理解:把灰度级理解为假象地貌中某个位置的海拔高度,顶面就是海拔高度函数)。

   1.2顶面函数f的本影:本影的一般定义为,一个不透明物体遮挡光线而形成的完全阴影区域,在数学形态学中,函数f的本影定义为一个由f的顶面及其下所有点构成的集合。

二 灰度级腐蚀和膨胀

    2.1 灰度级腐蚀

       基本步骤:(1)计算它们的本影 (2)对本影采用二值腐蚀 (3)计算顶面即为结果

    2.2灰度级膨胀

       基本步骤:(1)计算它们的本影 (2)对本影采用二值膨胀 (3)计算顶面即为结果

    以上只要理解好了本影就好了。对于灰度级的腐蚀和膨胀理解要借助一些图形,这里主要参考(MilanSonka 、Valav Hlavac、Roger Boyle 图像处理、分析与机器视觉(第三版) 十三章)

三 C语言实现(摘自百度文库)

    具体的文档可在资源里下载http://download.csdn.net/detail/caiye917015406/4460983

下面的这段程序,实现了上述的腐蚀运算,针对的都是黑色点。参数中有一个BOOL变量,为真时,表示在水平方向进行腐蚀运算,即结构元素B;否则在垂直方向上进行腐蚀运算,即结构元素B

BOOLErosion(HWND hWnd,BOOL Hori)

{

      DWORD                            OffBits,BufSize;

LPBITMAPINFOHEADER   lpImgData;

      LPSTR                  lpPtr;

      HLOCAL                 hTempImgData;

      LPBITMAPINFOHEADER    lpTempImgData;

      LPSTR                          lpTempPtr;

      HDC                     hDc;

      HFILE                   hf;

      LONG                   x,y;

      unsigned char             num;

      int                       i;

//为了处理方便,仍采用256级灰度图,不过只用调色板中0255两项

if(NumColors!=256){ 

          MessageBox(hWnd,"Must be a monobitmap with grayscale palette!",

"ErrorMessage",MB_OK|MB_ICONEXCLAMATION);

return FALSE;

}

OffBits=bf.bfOffBits-sizeof(BITMAPFILEHEADER);

//BufSize为缓冲区大小

      BufSize=OffBits+bi.biHeight*LineBytes;

      //为新的缓冲区分配内存

      if((hTempImgData=LocalAlloc(LHND,BufSize))==NULL)

{

           MessageBox(hWnd,"Erroralloc memory!","Error Message",

MB_OK|MB_ICONEXCLAMATION);

return FALSE;

   }

    lpImgData=(LPBITMAPINFOHEADER)GlobalLock(hImgData);   

      lpTempImgData=(LPBITMAPINFOHEADER)LocalLock(hTempImgData);

      //拷贝头信息和位图数据    

      memcpy(lpTempImgData,lpImgData,BufSize);

      if(Hori)

      {  

//在水平方向进行腐蚀运算

             for(y=0;y<bi.biHeight;y++){

                    //lpPtr指向原图数据,lpTempPtr指向新图数据

                    lpPtr=(char *)lpImgData+(BufSize-LineBytes-y*LineBytes)+1;

                    lpTempPtr=(char*)lpTempImgData+

(BufSize-LineBytes-y*LineBytes)+1;

                    for(x=1;x<bi.biWidth-1;x++){

//注意为防止越界,x的范围从1到宽度-2

                           num=(unsigned char)*lpPtr;

                           if (num==0){  //因为腐蚀掉的是黑点,所以只对黑点处理

                                  *lpTempPtr=(unsigned char)0;  //先置成黑点

                                  for(i=0;i<3;i++){

                                         num=(unsigned char)*(lpPtr+i-1);

                                         if(num==255){

//自身及上下邻居中若有一个不是黑点,则将该点腐

//蚀成白点

                                                *lpTempPtr=(unsigned char)255;

                                                break;

                                         }

                                  }

                           }

//原图中就是白点的,新图中仍是白点

                           else *lpTempPtr=(unsigned char)255; 

                           //指向下一个象素

                           lpPtr++;

                           lpTempPtr++;

                    }

             }

      }

else{

//在垂直方向进行腐蚀运算

             for(y=1;y<bi.biHeight-1;y++){ //注意为防止越界,y的范围从1到高度-2

                    //lpPtr指向原图数据,lpTempPtr指向新图数据

                    lpPtr=(char *)lpImgData+(BufSize-LineBytes-y*LineBytes);

                    lpTempPtr=(char *)lpTempImgData+(BufSize-LineBytes-y*LineBytes);

                    for(x=0;x<bi.biWidth;x++){

                           num=(unsigned char)*lpPtr;

                           if (num==0){ //因为腐蚀掉的是黑点,所以只对黑点处理

                                  *lpTempPtr=(unsigned char)0; //先置成黑点

                                  for(i=0;i<3;i++){

                                         num=(unsigned char)*(lpPtr+(i-1)*LineBytes);

                                         if(num==255){

//自身及上下邻居中若有一个不是黑点,则将该点腐

//蚀成白点

                                                *lpTempPtr=(unsigned char)255;

                                                break;

                                         }

                                  }

                           }

//原图中就是白点的,新图中仍是白点

                           else *lpTempPtr=(unsigned char)255;

                           //指向下一个象素

                           lpPtr++;

                           lpTempPtr++;

                    }

             }

      }

   if(hBitmap!=NULL)

          DeleteObject(hBitmap);

      hDc=GetDC(hWnd);    

      //产生新的位图

      hBitmap=CreateDIBitmap(hDc,(LPBITMAPINFOHEADER)lpTempImgData,

(LONG)CBM_INIT,

(LPSTR)lpTempImgData+

sizeof(BITMAPINFOHEADER)+

                                        NumColors*sizeof(RGBQUAD),

(LPBITMAPINFO)lpTempImgData,DIB_RGB_COLORS);

      //起不同的结果文件名

      if(Hori)

             hf=_lcreat("c:\\herosion.bmp",0);

      else

             hf=_lcreat("c:\\verosion.bmp",0);

      _lwrite(hf,(LPSTR)&bf,sizeof(BITMAPFILEHEADER));

      _lwrite(hf,(LPSTR)lpTempImgData,BufSize);

      _lclose(hf);

      //释放内存及资源

ReleaseDC(hWnd,hDc);

      LocalUnlock(hTempImgData);

      LocalFree(hTempImgData);

      GlobalUnlock(hImgData);

      return TRUE;

}

下面的这段程序,实现了上述的膨胀运算,针对的都是黑色点。参数中有一个BOOL变量,为真时,表示在水平方向进行膨胀运算,即结构元素B;否则在垂直方向上进行膨胀运算,即结构元素B

BOOLDilation(HWND hWnd,BOOL Hori)

{

      DWORD                           OffBits,BufSize;

LPBITMAPINFOHEADER   lpImgData;

      LPSTR                  lpPtr;

      HLOCAL                 hTempImgData;

      LPBITMAPINFOHEADER    lpTempImgData;

      LPSTR                   lpTempPtr;

      HDC                    hDc;

      HFILE                   hf;

      LONG                  x,y;

      unsigned char             num;

      int                       i;

//为了处理的方便,仍采用256级灰度图,不过只调色板中0255两项

if(NumColors!=256){ 

           MessageBox(hWnd,"Must bea mono bitmap with grayscale palette!",

"ErrorMessage",MB_OK|MB_ICONEXCLAMATION);

return FALSE;

}

OffBits=bf.bfOffBits-sizeof(BITMAPFILEHEADER);

//BufSize为缓冲区大小

      BufSize=OffBits+bi.biHeight*LineBytes;

//为新的缓冲区分配内存

      if((hTempImgData=LocalAlloc(LHND,BufSize))==NULL)

   {

          MessageBox(hWnd,"Error allocmemory!","Error Message",

MB_OK|MB_ICONEXCLAMATION);

return FALSE;

   }

    lpImgData=(LPBITMAPINFOHEADER)GlobalLock(hImgData);   

      lpTempImgData=(LPBITMAPINFOHEADER)LocalLock(hTempImgData);

      //拷贝头信息和位图数据    

      memcpy(lpTempImgData,lpImgData,BufSize);

      if(Hori)

      {  

//在水平方向进行膨胀运算

             for(y=0;y<bi.biHeight;y++){

                    //lpPtr指向原图数据,lpTempPtr指向新图数据

                    lpPtr=(char *)lpImgData+(BufSize-LineBytes-y*LineBytes)+1;

                    lpTempPtr=(char*)lpTempImgData+

(BufSize-LineBytes-y*LineBytes)+1;

                    for(x=1;x<bi.biWidth-1;x++){

//注意为防止越界,x的范围从1到宽度-2

                           num=(unsigned char)*lpPtr;

//原图中是黑点的,新图中肯定也是,所以要考虑的是那些原图

//中的白点,看是否有可能膨胀成黑点

                           if (num==255){

                                 *lpTempPtr=(unsigned char)255; //先置成白点

                                  for(i=0;i<3;i++){

                                         num=(unsigned char)*(lpPtr+i-1);

//只要左右邻居中有一个是黑点,就膨胀成黑点

                                         if(num==0){

*lpTempPtr=(unsignedchar)0;

                                                break;

                                         }

                                  }

                           }

//原图中就是黑点的,新图中仍是黑点

                           else *lpTempPtr=(unsigned char)0;

                           //指向下一个象素

                           lpPtr++;

                           lpTempPtr++;

                    }

             }

      }

      else{

//在垂直方向进行腐蚀运算

             for(y=1;y<bi.biHeight-1;y++){ //注意为防止越界,y的范围从1到高度-2

             lpPtr=(char *)lpImgData+(BufSize-LineBytes-y*LineBytes);

                    lpTempPtr=(char *)lpTempImgData+(BufSize-LineBytes-y*LineBytes);

                    for(x=0;x<bi.biWidth;x++){

                           num=(unsigned char)*lpPtr;

                           if (num==255){

                                  *lpTempPtr=(unsigned char)255;

                                  for(i=0;i<3;i++){

                                         num=(unsigned char)*(lpPtr+(i-1)*LineBytes);

//只要上下邻居中有一个是黑点,就膨胀成黑点

                                         if(num==0){

                                                *lpTempPtr=(unsigned char)0;

                                                break;

                                         }

                                  }

                           }

                           else *lpTempPtr=(unsigned char)0;

                           lpPtr++;

                           lpTempPtr++;

                    }

             }

      }

   if(hBitmap!=NULL)

          DeleteObject(hBitmap);

      hDc=GetDC(hWnd);    

      //产生新的位图

      hBitmap=CreateDIBitmap(hDc,(LPBITMAPINFOHEADER)lpTempImgData,

(LONG)CBM_INIT,

(LPSTR)lpTempImgData+

sizeof(BITMAPINFOHEADER)+

                                        NumColors*sizeof(RGBQUAD),

(LPBITMAPINFO)lpTempImgData,

DIB_RGB_COLORS);

      //起不同的结果文件名

      if(Hori)

             hf=_lcreat("c:\\hdilation.bmp",0);

      else

             hf=_lcreat("c:\\vdilation.bmp",0);

      _lwrite(hf,(LPSTR)&bf,sizeof(BITMAPFILEHEADER));

      _lwrite(hf,(LPSTR)lpTempImgData,BufSize);

      _lclose(hf);

      //释放内存及资源

     ReleaseDC(hWnd,hDc);

      LocalUnlock(hTempImgData);

      LocalFree(hTempImgData);

      GlobalUnlock(hImgData);

      return TRUE;

}

我们可以根据上述的判据,事先做出一张表,从0255共有256个元素,每个元素要么是0,要么是1。我们根据某点(当然是要处理的黑色点了)的八个相邻点的情况查表,若表中的元素是1,则表示该点可删,否则保留。

查表的方法是,设白点为1,黑点为0;左上方点对应一个8位数的第一位(最低位),正上方点对应第二位,右上方点对应的第三位,左邻点对应第四位,右邻点对应第五位,左下方点对应第六位,正下方点对应第七位,右下方点对应的第八位,按这样组成的8位数去查表即可。例如上面的例子中(1)对应表中的第0项,该项应该为0(2)对应37,该项应该为0(3)对应173,该项应该为1(4)对应231,该项应该为0(5)对应237,该项应该为1(6)对应254,该项应该为0(7)对应255,该项应该为0

这张表我已经替大家做好了,可花了我不少时间呢!

static interasetable[256]={

                                        0,0,1,1,0,0,1,1,         1,1,0,1,1,1,0,1,

                                  1,1,0,0,1,1,1,1,            0,0,0,0,0,0,0,1,

                                       0,0,1,1,0,0,1,1,            1,1,0,1,1,1,0,1,

                                       1,1,0,0,1,1,1,1,            0,0,0,0,0,0,0,1,

                                       1,1,0,0,1,1,0,0,            0,0,0,0,0,0,0,0,

                                        0,0,0,0,0,0,0,0,            0,0,0,0,0,0,0,0,

                                         1,1,0,0,1,1,0,0,            1,1,0,1,1,1,0,1,

                                  0,0,0,0,0,0,0,0,            0,0,0,0,0,0,0,0,

                         0,0,1,1,0,0,1,1,            1,1,0,1,1,1,0,1,

                                       1,1,0,0,1,1,1,1,            0,0,0,0,0,0,0,1,

                                       0,0,1,1,0,0,1,1,            1,1,0,1,1,1,0,1,

                                       1,1,0,0,1,1,1,1,            0,0,0,0,0,0,0,0,

                                        1,1,0,0,1,1,0,0,            0,0,0,0,0,0,0,0,

                              1,1,0,0,1,1,1,1,            0,0,0,0,0,0,0,0,

                                         1,1,0,0,1,1,0,0,            1,1,0,1,1,1,0,0,

                                  1,1,0,0,1,1,1,0,            1,1,0,0,1,0,0,0

                                  };

 

以下是源程序,黑体字部分是值得注意的地方。

BOOLThinning(HWND hWnd)

{

      DWORD                            OffBits,BufSize;

    LPBITMAPINFOHEADER    lpImgData;

      LPSTR                          lpPtr;

      HLOCAL                 hTempImgData;

      LPBITMAPINFOHEADER    lpTempImgData;

      LPSTR                  lpTempPtr;

      HDC                     hDc;

      HFILE                   hf;

      LONG                   x,y;

      int                                      num;

      BOOL                    Finished;

      int                       nw,n,ne,w,e,sw,s,se;

//为了处理的方便,仍采用256级灰度图,不过只用调色板中0255两项

      if( NumColors!=256){

MessageBox(hWnd,"Mustbe a mono bitmap with grayscale palette!",

"ErrorMessage",MB_OK|MB_ICONEXCLAMATION);

return FALSE;

}

OffBits=bf.bfOffBits-sizeof(BITMAPFILEHEADER);

//BufSize为缓冲区大小

      BufSize=OffBits+bi.biHeight*LineBytes;

//为新的缓冲区分配内存

      if((hTempImgData=LocalAlloc(LHND,BufSize))==NULL)

{

           MessageBox(hWnd,"Erroralloc memory!","Error Message",

MB_OK|MB_ICONEXCLAMATION);

return FALSE;

}

    lpImgData=(LPBITMAPINFOHEADER)GlobalLock(hImgData);   

      lpTempImgData=(LPBITMAPINFOHEADER)LocalLock(hTempImgData);

      //拷贝头信息和位图数据    

      memcpy(lpTempImgData,lpImgData,BufSize);

      //结束标志置成假

      Finished=FALSE;

while(!Finished){//还没有结束

             //结束标志置成假

           Finished=TRUE;

      //先进行水平方向的细化

             for (y=1;y<bi.biHeight-1;y++){ //注意为防止越界,y的范围从1到高度-2

                    //lpPtr指向原图数据,lpTempPtr指向新图数据

                    lpPtr=(char *)lpImgData+(BufSize-LineBytes-y*LineBytes);

                    lpTempPtr=(char *)lpTempImgData+(BufSize-LineBytes-y*LineBytes);

                    x=1; //注意为防止越界,x的范围从1到宽度-2

                    while(x<bi.biWidth-1){

                           if(*(lpPtr+x)==0){ //是黑点才做处理

                                  w=(unsigned char)*(lpPtr+x-1);  //左邻点

                                  e=(unsigned char)*(lpPtr+x+1);  //右邻点

                                  if( (w==255)|| (e==255)){

//如果左右两个邻居中至少有一个是白点才处理

                                         nw=(unsigned char)*(lpPtr+x+LineBytes-1); //左上邻点

                                         n=(unsigned char)*(lpPtr+x+LineBytes); //上邻点

                                         ne=(unsigned char)*(lpPtr+x+LineBytes+1); //右上邻点

                                         sw=(unsigned char)*(lpPtr+x-LineBytes-1); //左下邻点

                                         s=(unsigned char)*(lpPtr+x-LineBytes); //下邻点

                                         se=(unsigned char)*(lpPtr+x-LineBytes+1); //右下邻点

                                         //计算索引

                           num=nw/255+n/255*2+ne/255*4+w/255*8+e/255*16+

sw/255*32+s/255*64+se/255*128;

                                         if(erasetable[num]==1){ //经查表,可以删除

//在原图缓冲区中将该黑点删除

                                                *(lpPtr+x)=(BYTE)255;

//结果图中该黑点也删除

                                                *(lpTempPtr+x)=(BYTE)255;

                                                Finished=FALSE; //有改动,结束标志置成假

                                                x++; //水平方向跳过一个象素

                                         }

                                  }

                           }

                           x++; //扫描下一个象素

                    }

             }

      //再进行垂直方向的细化

             for (x=1;x<bi.biWidth-1;x++){ //注意为防止越界,x的范围从1到宽度-2

                    y=1; //注意为防止越界,y的范围从1到高度-2

                    while(y<bi.biHeight-1){

                           lpPtr=(char *)lpImgData+(BufSize-LineBytes-y*LineBytes);

                           lpTempPtr=(char*)lpTempImgData+

(BufSize-LineBytes-y*LineBytes);

                           if(*(lpPtr+x)==0){ //是黑点才做处理

                                  n=(unsigned char)*(lpPtr+x+LineBytes);

                                  s=(unsigned char)*(lpPtr+x-LineBytes);

                                  if( (n==255)|| (s==255)){

//如果上下两个邻居中至少有一个是白点才处理

                                         nw=(unsigned char)*(lpPtr+x+LineBytes-1);

                                         ne=(unsigned char)*(lpPtr+x+LineBytes+1);

                                         w=(unsigned char)*(lpPtr+x-1);

                                         e=(unsigned char)*(lpPtr+x+1);

                                         sw=(unsigned char)*(lpPtr+x-LineBytes-1);

                                         se=(unsigned char)*(lpPtr+x-LineBytes+1);

                                         //计算索引

num=nw/255+n/255*2+ne/255*4+w/255*8+e/255*16+

sw/255*32+s/255*64+se/255*128;

                                         if(erasetable[num]==1){ //经查表,可以删除

//在原图缓冲区中将该黑点删除

                                                *(lpPtr+x)=(BYTE)255;

//结果图中该黑点也删除

                                                *(lpTempPtr+x)=(BYTE)255;

                                                Finished=FALSE; //有改动,结束标志置成假

                                                y++;//垂直方向跳过一个象素

                                         }

                                  }

                           }

                           y++; //扫描下一个象素

                    }

             }

}

    if(hBitmap!=NULL)

          DeleteObject(hBitmap);

      hDc=GetDC(hWnd);    

      //产生新的位图

      hBitmap=CreateDIBitmap(hDc,(LPBITMAPINFOHEADER)lpTempImgData,

(LONG)CBM_INIT,

(LPSTR)lpTempImgData+

sizeof(BITMAPINFOHEADER)+

NumColors*sizeof(RGBQUAD),

(LPBITMAPINFO)lpTempImgData,

DIB_RGB_COLORS);

hf=_lcreat("c:\\thinning.bmp",0);

      _lwrite(hf,(LPSTR)&bf,sizeof(BITMAPFILEHEADER));

      _lwrite(hf,(LPSTR)lpTempImgData,BufSize);

      _lclose(hf);

      //释放内存及资源

     ReleaseDC(hWnd,hDc);

      LocalUnlock(hTempImgData);

      LocalFree(hTempImgData);

      GlobalUnlock(hImgData);

      return TRUE;

}

 

 

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