void Cooccurrence (ImSize, CoSize, Dy,Dx, InIm, CoMa)
int  ImSize, CoSize, Dy,Dx;
BYTE ** InIm;
int  ** CoMa;
{
   int  r,c, a,b, o, Resol;

   Resol = 256 / CoSize;
   for (r=0; r<ImSize; r++)
      for (c=0; c<ImSize; c++)  CoMa [r][c] = 0;

   o = MaxAbs (Dx,Dy);
   for (r=o; r<ImSize-o; r++) {
      for (c=o; c<ImSize-o; c++) {
         a = InIm [r][c] / Resol;
         b = InIm [r+Dy][c+Dx] / Resol;
         CoMa [a][b] ++;
}  }  }
