/// <summary>
        /// 3×3中值滤波除杂，yuanbao,2007.10
        /// </summary>
        /// <param name="dgGrayValue"></param>
        public void ClearNoise(int dgGrayValue)
        {
            int x, y;
            byte[] p = new byte[9]; //最小处理窗口3*3
            byte s;
            //byte[] lpTemp=new BYTE[nByteWidth*nHeight];
            int i, j;

            //--!!!!!!!!!!!!!!下面开始窗口为3×3中值滤波!!!!!!!!!!!!!!!!
            for (y = 1; y < bmpobj.Height - 1; y++) //--第一行和最后一行无法取窗口
            {
                for (x = 1; x < bmpobj.Width - 1; x++)
                {
                    //取9个点的值
                    p[0] = bmpobj.GetPixel(x - 1, y - 1).R;
                    p[1] = bmpobj.GetPixel(x, y - 1).R;
                    p[2] = bmpobj.GetPixel(x + 1, y - 1).R;
                    p[3] = bmpobj.GetPixel(x - 1, y).R;
                    p[4] = bmpobj.GetPixel(x, y).R;
                    p[5] = bmpobj.GetPixel(x + 1, y).R;
                    p[6] = bmpobj.GetPixel(x - 1, y + 1).R;
                    p[7] = bmpobj.GetPixel(x, y + 1).R;
                    p[8] = bmpobj.GetPixel(x + 1, y + 1).R;
                    //计算中值
                    for (j = 0; j < 5; j++)
                    {
                        for (i = j + 1; i < 9; i++)
                        {
                            if (p[j] > p[i])
                            {
                                s = p[j];
                                p[j] = p[i];
                                p[i] = s;
                            }
                        }
                    }
              //      if (bmpobj.GetPixel(x, y).R < dgGrayValue)
                        bmpobj.SetPixel(x, y, Color.FromArgb(p[4], p[4], p[4]));    //给有效值付中值
                }
            }
        }