图像处理：怎么得到黑白边缘点的坐标？

Question

从上到下在内存中寻找黑白交接点，很简单的，只要查找每条线上各个像素的值，发现结果突然接近0的时候就是你要找的Y坐标.
另外：BMP的原点(0, 0)是在图片的左下方。

Answer 1

在这里不是很容易说清楚，因为涉及到图片的色深和Width.如果你会Load位图，能够得到象素位的指针，我可以教你怎样算，否则就比较麻烦。你也可以参考<<Windows程序设计>>第十五章“与设备无关的位图”，

Answer 2

位图的格式我已经很清楚了。我可以得到那条直线的RGB值了，并且可以转化为灰度值(0-255)。

Answer 3

#include "stdafx.h"
#include "dibapi.h"
#include <io.h>
#include <errno.h>#include <math.h>
#include <direct.h>#define PI 3.1415926535
//*Dib文件头标志（写字符"BM",写DIB时用到该常数）
#define DIB_HEADER_MARKER ((WORD)('M'<<8)|'B')BOOL  WINAPI PaintDIB(HDC hDC,LPRECT lpDCRect,HDIB hDIB,LPRECT lpDIBRect,CPalette *pPal)
{
LPSTR lpDIBHdr;
LPSTR lpDIBBits;
BOOL bSuccess=FALSE;
HPALETTE hPal=NULL;
HPALETTE hOldPal;
if(hDIB==NULL)
return FALSE;
lpDIBHdr=(LPSTR)::GlobalLock((HGLOBAL)hDIB);
lpDIBBits=::FindDIBBits(lpDIBHdr);
if(pPal!=NULL)
{
hPal=(HPALETTE)pPal->m_hObject;
hOldPal=::SelectPalette(hDC,hPal,TRUE);
}
::SetStretchBltMode(hDC,COLORONCOLOR);
if((RECTWIDTH(lpDCRect)==RECTWIDTH(lpDIBRect))&&(RECTHEIGHT(lpDCRect)==RECTHEIGHT(lpDIBRect)))
{
bSuccess=::SetDIBitsToDevice(hDC,lpDCRect->left,lpDCRect->top,
                         RECTWIDTH(lpDCRect),RECTHEIGHT(lpDCRect),
 lpDIBRect->left,(int)DIBHeight(lpDIBHdr)-lpDIBRect->top-RECTHEIGHT(lpDIBRect),
 0,(WORD)DIBHeight(lpDIBHdr),lpDIBBits,
 (LPBITMAPINFO)lpDIBHdr,DIB_RGB_COLORS);
}
else
{
bSuccess=::StretchDIBits(hDC,lpDCRect->left,lpDCRect->top,
                     RECTWIDTH(lpDCRect),RECTHEIGHT(lpDCRect),
 lpDIBRect->left,lpDIBRect->top,
 RECTWIDTH(lpDIBRect),RECTHEIGHT(lpDIBRect),
 lpDIBBits,(LPBITMAPINFO)lpDIBHdr,DIB_RGB_COLORS,SRCCOPY);
}
::GlobalUnlock((HGLOBAL)hDIB);
if(hOldPal!=NULL)
{
::SelectPalette(hDC,hOldPal,TRUE);
}
return bSuccess;
}
BOOL  WINAPI CreateDIBPalette(HDIB hDIB,CPalette *cPal)
{
LPLOGPALETTE lpPal;
HANDLE hLogPal;
HPALETTE hPal=NULL;
int i;
WORD wNumColors;
LPSTR lpbi;
LPBITMAPINFO lpbmi;
LPBITMAPCOREINFO lpbmc;
BOOL bWinStyleDIB;
BOOL bResult=FALSE;
if(hDIB==NULL)
return FALSE;
lpbi=(LPSTR)::GlobalLock((HGLOBAL)hDIB);
lpbmi=(LPBITMAPINFO)lpbi;
lpbmc=(LPBITMAPCOREINFO)lpbi;
wNumColors=::DIBNumColors(lpbi);
if(wNumColors!=0)
{
hLogPal=::GlobalAlloc(GHND,sizeof(LOGPALETTE)+sizeof(PALETTEENTRY)*wNumColors);
if(hLogPal==0)
{
::GlobalUnlock((HGLOBAL)hDIB);
return FALSE;
}
lpPal=(LPLOGPALETTE)::GlobalLock((HGLOBAL)hLogPal);
lpPal->palVersion=PALVERSION;
lpPal->palNumEntries=(WORD)wNumColors;
bWinStyleDIB=IS_WIN30_DIB(lpbi);
for(i=0;i<(int)wNumColors;i++)
{
if(bWinStyleDIB)
{
lpPal->palPalEntry[i].peRed=lpbmi->bmiColors[i].rgbRed;
lpPal->palPalEntry[i].peGreen=lpbmi->bmiColors[i].rgbGreen;
lpPal->palPalEntry[i].peBlue=lpbmi->bmiColors[i].rgbBlue;
lpPal->palPalEntry[i].peFlags=0;
}
else
{
lpPal->palPalEntry[i].peRed=lpbmc->bmciColors[i].rgbtRed;
lpPal->palPalEntry[i].peGreen=lpbmc->bmciColors[i].rgbtGreen;
lpPal->palPalEntry[i].peBlue=lpbmc->bmciColors[i].rgbtBlue;
lpPal->palPalEntry[i].peFlags=0;
} }
bResult=cPal->CreatePalette(lpPal);
::GlobalUnlock((HGLOBAL)hLogPal);
::GlobalFree((HGLOBAL)hLogPal); }
::GlobalUnlock((HGLOBAL)hDIB);
return bResult;
}
LPSTR WINAPI FindDIBBits(LPSTR lpbi)
{
return (lpbi+*(LPDWORD)lpbi+::PaletteSize(lpbi));
}
DWORD WINAPI DIBWidth(LPSTR lpDIB)
{
LPBITMAPINFOHEADER lpbmi;
LPBITMAPCOREHEADER lpbmc; lpbmi=(LPBITMAPINFOHEADER)lpDIB;
lpbmc=(LPBITMAPCOREHEADER)lpDIB;
if(IS_WIN30_DIB(lpDIB))
  return lpbmi->biWidth;
else
return (DWORD)lpbmc->bcWidth;
}
DWORD WINAPI DIBHeight(LPSTR lpDIB)
{
LPBITMAPINFOHEADER lpbmi;
LPBITMAPCOREHEADER lpbmc; lpbmi=(LPBITMAPINFOHEADER)lpDIB;
lpbmc=(LPBITMAPCOREHEADER)lpDIB;
if(IS_WIN30_DIB(lpDIB))
  return lpbmi->biHeight;
else
return (DWORD)lpbmc->bcHeight;}
WORD  WINAPI PaletteSize(LPSTR lpbi)
{
if(IS_WIN30_DIB(lpbi))
{
return (WORD)(::DIBNumColors(lpbi)*sizeof(RGBQUAD));
}
else
return (WORD)(::DIBNumColors(lpbi)*sizeof(RGBTRIPLE));
}
WORD  WINAPI DIBNumColors(LPSTR lpbi)
{
WORD wBitCount;
if(IS_WIN30_DIB(lpbi))
{
DWORD dwClrUsed=((LPBITMAPINFOHEADER)lpbi)->biClrUsed;
if(dwClrUsed!=0)
return (WORD)dwClrUsed;
}
if(IS_WIN30_DIB(lpbi))
{
wBitCount=((LPBITMAPINFOHEADER)lpbi)->biBitCount;
}
else
{
wBitCount=((LPBITMAPCOREHEADER)lpbi)->bcBitCount;
}
switch(wBitCount)
{
case 1:
return 2;
case 4:
return 16;
case 8:
return 256;
default:
return 0; }

}
HGLOBAL WINAPI CopyHandle(HGLOBAL h)
{
if(h==NULL)
return NULL;
DWORD dwLen=::GlobalSize((HGLOBAL)h);
HGLOBAL hCopy=::GlobalAlloc(GHND,dwLen);
if(hCopy!=NULL)
{
void *lpCopy=::GlobalLock((HGLOBAL)hCopy);
void *lp=::GlobalLock((HGLOBAL)h);
memcpy(lpCopy,lp,dwLen);
::GlobalUnlock(hCopy);
::GlobalUnlock(h);
}
return hCopy;
}
BOOL WINAPI SaveDIB(HDIB hDib,CFile &file)
{
BITMAPFILEHEADER bmfHdr;
LPBITMAPINFOHEADER lpBI;
DWORD dwDIBSize;
if(hDib==NULL)
{
return FALSE;
}
lpBI=(LPBITMAPINFOHEADER)::GlobalLock((HGLOBAL)hDib);
if(lpBI==NULL)
return FALSE;
if(!IS_WIN30_DIB(lpBI))
{
::GlobalUnlock((HGLOBAL)hDib);
return FALSE;
}
bmfHdr.bfType=DIB_HEADER_MARKER;
dwDIBSize=*(LPDWORD)lpBI+::PaletteSize((LPSTR)lpBI);
if((lpBI->biCompression==BI_RLE8)||(lpBI->biCompression==BI_RLE4))
dwDIBSize+=lpBI->biSizeImage;
else
{
DWORD dwBmBitsSize;
dwBmBitsSize=WIDTHBYTES((lpBI->biWidth)*((DWORD)lpBI->biBitCount))*lpBI->biHeight;
dwDIBSize+=dwBmBitsSize;
lpBI->biSizeImage=dwBmBitsSize;
}
bmfHdr.bfSize=dwDIBSize+sizeof(BITMAPFILEHEADER);
bmfHdr.bfReserved1=0;
bmfHdr.bfReserved2=0;
bmfHdr.bfOffBits=(DWORD)sizeof(BITMAPFILEHEADER)+lpBI->biSize+PaletteSize((LPSTR)lpBI);
TRY
{
file.Write((LPSTR)&bmfHdr,sizeof(BITMAPFILEHEADER));
file.WriteHuge(lpBI,dwDIBSize);
}
CATCH(CFileException,e)
{
::GlobalUnlock((HGLOBAL)hDib);
THROW_LAST();
}
END_CATCH
::GlobalUnlock((HGLOBAL)hDib);
    return TRUE;

}
HDIB WINAPI ReadDIBFile(CFile &file)
{
   BITMAPFILEHEADER bmfHeader;
   DWORD dwBitsSize;
   HDIB hDIB;
   LPSTR pDIB;
   dwBitsSize=file.GetLength();
   if(file.Read((LPSTR)&bmfHeader,sizeof(bmfHeader))!=sizeof(bmfHeader))
   return NULL;
   if(bmfHeader.bfType!=DIB_HEADER_MARKER)
   {
   return NULL;
   }
   hDIB=(HDIB)::GlobalAlloc(GMEM_MOVEABLE|GMEM_ZEROINIT,dwBitsSize);
   if(hDIB==0)
   return NULL;
   pDIB=(LPSTR)::GlobalLock((HGLOBAL)hDIB);
   if(file.ReadHuge(pDIB,dwBitsSize-sizeof(BITMAPFILEHEADER))!=dwBitsSize-sizeof(BITMAPFILEHEADER))
   {
   ::GlobalUnlock((HGLOBAL)hDIB);
   ::GlobalFree((HGLOBAL)hDIB);
   return NULL;
   }
   ::GlobalUnlock((HGLOBAL)hDIB);
   return hDIB;
}

Answer 4

//=======================离散余弦变换==========================
VOID WINAPI DCT(double *f,double *F,int r)
{
long count=1<<r;
   int i;
   double dTemp;
   complex<double>*X;
   X=new complex<double>[count*2];
   memset(X,0,sizeof(complex<double>)*count*2);
   for(i=0;i<count;i++)
   X[i]=complex<double>(f[i],0);
   FFT(X,X,r+1);
   dTemp=1/sqrt(count);
   F[0]=X[0].real()*dTemp;
   dTemp*=sqrt(2);
   for(i=1;i<count;i++)
   {
     F[i]=(X[i].real()*cos(i*PI/(count*2))+X[i].imag()*sin(i*PI/(count*2)))*dTemp;
   }
   delete X;
}
VOID WINAPI IDCT(double *F,double *f,int r)
{
long count=1<<r;
   int i;
   double dTemp,d0;
   complex<double>*X;
   X=new complex<double>[count*2];
   memset(X,0,sizeof(complex<double>)*count*2);
   for(i=0;i<count;i++)
   X[i]=complex<double>(F[i]*cos(i*PI/(count*2)),F[i]*sin(i*PI/(count*2)));   IFFT(X,X,r+1);
   dTemp=sqrt(2.0/count);
   d0=(sqrt(1.0/count)-dTemp)*F[0];
   for(i=0;i<count;i++)
   f[i]=d0+X[i].real()*dTemp*2*count;   delete X;
}
BOOL WINAPI DIBDct(LPSTR lpDIBBits,LONG lWidth,LONG lHeight)
{   unsigned char *lpSrc;   long i,j;
   long h=1,w=1;
   int hp=0,wp=0;
   double dTemp;
   long lLineBytes=WIDTHBYTES(lWidth*8);
   while(w*2<=lWidth)
   {
      w*=2;wp++;
   }
   while(h*2<=lHeight)
   {
      h*=2;hp++;
   }
   double *f=new double[w*h];
   double *F=new double[w*h];
   for(i=0;i<h;i++)
   {
      for(j=0;j<w;j++)
      {
 lpSrc=(unsigned char*)lpDIBBits+lLineBytes*(lHeight-1-i)+j;
         f[j+i*w]=*(lpSrc);
      }
   }
   for(i=0;i<h;i++)
   DCT(&f[w*i],&F[w*i],wp);
   for(i=0;i<h;i++)
   {
      for(j=0;j<w;j++)
      f[i+j*h]=F[j+i*w];
   }
   for(j=0;j<w;j++)
   DCT(&f[j*h],&F[j*h],hp);
   for(i=0;i<h;i++)
   {
      for(j=0;j<w;j++)
      {
  dTemp=fabs(F[j*h+i]);
          if(dTemp>255)
          dTemp=255;
          lpSrc=(unsigned char*)lpDIBBits+lLineBytes*(lHeight-1-i)+j;
      *(lpSrc)=(BYTE)(dTemp);
  }
   }
   delete f;
   delete F;
   return TRUE;
}
//===============细化========================================
BOOL WINAPI ThiningDIB(LPSTR lpDIBBits,LONG lWidth,LONG lHeight)
{   LPSTR lpSrc;
   LPSTR lpDest;
   LPSTR lpNewDIBBits;
   HLOCAL hNewDIBBits;   bool bModified=true;
   long i,j;
   int m,n;
   bool bCondition1,bCondition2,bCondition3,bCondition4;
   unsigned char nCount;
   unsigned char pixel;
   unsigned char neighbour[5][5];
   hNewDIBBits=LocalAlloc(LHND,lWidth*lHeight);
   if(hNewDIBBits==NULL)
   {
   return FALSE;
   }
   lpNewDIBBits=(char*)LocalLock(hNewDIBBits);
   lpDest=(char*)lpNewDIBBits;
   memset(lpDest,(BYTE)255,lWidth*lHeight);    while(bModified)
   {
      bModified=false;
  lpDest=(char*)lpNewDIBBits;
  memset(lpDest,(BYTE)255,lWidth*lHeight);
      
  for(j=2;j<lHeight-2;j++)
      {
          for(i=2;i<lWidth-2;i++)
         {
            bCondition1=false;
            bCondition2=false;
            bCondition3=false;
            bCondition4=false;
            lpSrc=(char*)lpDIBBits+lWidth*j+i;
lpDest=(char*)lpNewDIBBits+lWidth*j+i;            pixel=(unsigned char)*lpSrc;
            if(pixel!=255&&*lpSrc!=0)
            {
               return FALSE;
            }
            else if(pixel==255)
            continue;
            for(m=0;m<5;m++)
            {
              for(n=0;n<5;n++)
              {                  neighbour[m][n]=(255-(unsigned char)*(lpSrc+((4-m)-2)*lWidth+n-2))/255;
              }
            }
            nCount=neighbour[1][1]+neighbour[1][2]+neighbour[1][3]+neighbour[2][1]+
                   neighbour[2][3]+neighbour[3][1]+neighbour[3][2]+neighbour[3][3];
            if(nCount>=2&&nCount<=6)
            bCondition1=true;
            nCount=0;
            if(neighbour[1][2]==0&&neighbour[1][1]==1)
            nCount++;
            if(neighbour[1][1]==0&&neighbour[2][1]==1)
            nCount++;
            if(neighbour[2][1]==0&&neighbour[3][1]==1)
            nCount++;
            if(neighbour[3][1]==0&&neighbour[3][2]==1)
            nCount++;
            if(neighbour[3][2]==0&&neighbour[3][3]==1)
            nCount++;
            if(neighbour[3][3]==0&&neighbour[2][3]==1)
            nCount++;
            if(neighbour[2][3]==0&&neighbour[1][3]==1)
            nCount++;
            if(neighbour[1][3]==0&&neighbour[1][2]==1)
            nCount++;
           if(nCount==1)
           bCondition2=true;           if(neighbour[1][2]*neighbour[2][1]*neighbour[2][3]==0)
           bCondition3=true;
           else
           {
             nCount=0;
             if(neighbour[0][2]==0&&neighbour[0][1]==1)
            nCount++;
            if(neighbour[0][1]==0&&neighbour[1][1]==1)
            nCount++;
            if(neighbour[1][1]==0&&neighbour[2][1]==1)
            nCount++;
            if(neighbour[2][1]==0&&neighbour[2][2]==1)
            nCount++;
            if(neighbour[2][2]==0&&neighbour[2][3]==1)
            nCount++;
            if(neighbour[2][3]==0&&neighbour[1][3]==1)
            nCount++;
            if(neighbour[1][3]==0&&neighbour[0][3]==1)
            nCount++;
            if(neighbour[0][3]==0&&neighbour[0][2]==1)
            nCount++;
           if(nCount!=1)
           bCondition3=true;           }
           if(neighbour[1][2]*neighbour[2][1]*neighbour[3][2]==0)
             bCondition4=true;
           else
           {
            nCount=0;
            if(neighbour[1][1]==0&&neighbour[1][0]==1)
            nCount++;
            if(neighbour[1][0]==0&&neighbour[2][0]==1)
            nCount++;
            if(neighbour[2][0]==0&&neighbour[3][0]==1)
            nCount++;
            if(neighbour[3][0]==0&&neighbour[3][1]==1)
            nCount++;
            if(neighbour[3][1]==0&&neighbour[3][2]==1)
            nCount++;
            if(neighbour[3][2]==0&&neighbour[2][2]==1)
            nCount++;
            if(neighbour[2][2]==0&&neighbour[1][2]==1)
            nCount++;
            if(neighbour[1][2]==0&&neighbour[1][1]==1)
            nCount++;
           if(nCount!=1)
           bCondition4=true;
           }
           if(bCondition1&&bCondition2&&bCondition3&&bCondition4)
           {
               *lpDest=(unsigned char)255;
               bModified=true;
           }
           else *lpDest=(unsigned char)0;
         }
      }
    memcpy(lpDIBBits,lpNewDIBBits,lWidth*lHeight);
 
   }
     memcpy(lpDIBBits,lpNewDIBBits,lWidth*lHeight);
 
   LocalUnlock(hNewDIBBits);
   LocalFree(hNewDIBBits);
   return TRUE;
}这是我学图象处理时的代码！

Answer 5

怎么叫交接处，是不是一个黑一个白中间加个灰的，灰的就是交接处呀，还是中间不知道有几个点呢？
如果中间一个点都没有就这样
  pData 指向数据段
 unsigned char *pSor;
 for(i=0;i<lHeight)
    {
     pSor=pData+lWidht*i+91;
     if(i!=lHeight-1)
       {
         if((*(pData+lWidht*(i+1))+91-*pSor)==255))||(*(pData+lWidht*(i+1))+91-*pSor)==-255)));//连着的两行比较一下
       return i;
        }     
    }

Answer 6

to： dycdyc123(重出江湖) ，多谢了，我好好研究研究。
to:   akiy(宏) 交接处就是灰的那一片，具体多灰色区域有多宽是不确定的。