7.Lọc Trung Vị

int M=pDoc->biHeader.biHeight;

          int N=pDoc->biHeader.biWidth;

          int i,j;

          int H[256];

          BYTE Y[1000][1000];

          int chiso,lc,k,l,K=3;

    //Giu bien

       for(i=0;i<M;i++)

              for (j=0;j<N;j++)

                    Y[i][j]=pDoc->Data[i][j];

    // tinh cac diem trong bien

                   lc=(3-1)/2;

          for (i=lc;i<=M-lc;i++)

                     for(j=lc;j<=N-lc;j++)

                                {

                                   chiso=0;

                                     for (k=-lc;k<=lc;k++)

                                       for (l=-lc;l<=lc;l++)

                                                   H[chiso++]=Y[i+k][j+l];

          //sap xep khong giam

                             for (k=0;k<K*K-1;k++)

                               for (l=k+1;l<K*K;l++)

                                       if (H[k]>H[l])

                                      { int tg=H[k];

                                         H[k]=H[l];

                                         H[l]=tg;

                                      }

                   //TÝnh Y[i,j]

                   pDoc->Data[i][j]=H[K*K/2];

                                }

      Invalidate();

}