/// <summary>
        /// Alpha filter.
        /// </summary>
        /// <param name="src">The source image.</param>
        /// <param name="tNumber">One parameter set from 0 to 9.</param>
        /// <returns></returns>
        public static WriteableBitmap AlphaFilterProcess(WriteableBitmap src, int tNumber)////修正的阿尔法滤波器
        {
            if (src != null)
            {
                int w = src.PixelWidth;
                int h = src.PixelHeight;
                WriteableBitmap filterImage = new WriteableBitmap(w, h);
                byte[] temp = src.PixelBuffer.ToArray();
                byte[] tempMask = (byte[])temp.Clone();
                double[] Gray = new double[9];
                double gray = 255;
                int tempr = 0, tempb = 0, tempg = 0;
                for (int j = 1; j < h - 1; j++)
                {
                    for (int i = 1; i < w - 1; i++)
                    {
                        tempb = 0;
                        tempg = 0;
                        tempr = 0;
                         
                        int[] B = new int[9] { tempMask[i * 4 + j * w * 4], tempMask[(i - 1) * 4 + (j - 1) * w * 4], tempMask[i * 4 + (j - 1) * w * 4], tempMask[(i + 1) * 4 + (j - 1) * w * 4], tempMask[(i - 1) * 4 + j * w * 4], tempMask[(i + 1) * 4 + j * w * 4], tempMask[(i - 1) * 4 + (j + 1) * w * 4], tempMask[i * 4 + (j + 1) * w * 4], tempMask[(i + 1) * 4 + (j + 1) * w * 4] };
                        int[] G = new int[9] { tempMask[i * 4 + 1 + j * w * 4], tempMask[(i - 1) * 4 + 1 + (j - 1) * w * 4], tempMask[i * 4 + 1 + (j - 1) * w * 4], tempMask[(i + 1) * 4 + 1 + (j - 1) * w * 4], tempMask[(i - 1) * 4 + 1 + j * w * 4], tempMask[(i + 1) * 4 + 1 + j * w * 4], tempMask[(i - 1) * 4 + 1 + (j + 1) * w * 4], tempMask[i * 4 + 1 + (j + 1) * w * 4], tempMask[(i + 1) * 4 + 1 + (j + 1) * w * 4] };
                        int[] R = new int[9] { tempMask[i * 4 + 2 + j * w * 4], tempMask[(i - 1) * 4 + 2 + (j - 1) * w * 4], tempMask[i * 4 + 2 + (j - 1) * w * 4], tempMask[(i + 1) * 4 + 2 + (j - 1) * w * 4], tempMask[(i - 1) * 4 + 2 + j * w * 4], tempMask[(i + 1) * 4 + 2 + j * w * 4], tempMask[(i - 1) * 4 + 2 + (j + 1) * w * 4], tempMask[i * 4 + 2 + (j + 1) * w * 4], tempMask[(i + 1) * 4 + 2 + (j + 1) * w * 4] };
                        for (int n = 0; n < 9; n++)
                        {
                            Gray[n] = (double)B[n] * 0.114 + (double)G[n] * 0.587 + (double)R[n] * 0.299;
                        }                                             
                        for (int x = 0; x < 9; x++)
                        {
                            for (int y = x + 1; y < 9; y++)
                            {
                                gray = Gray[x];
                                tempb = B[x];
                                tempg = G[x];
                                tempr = R[x];
                                if (Gray[x] > Gray[y])
                                {
                                    Gray[x] = Gray[y];
                                    Gray[y] = gray;
                                    B[x] = B[y];
                                    G[x] = G[y];
                                    R[x] = R[y];
                                    B[y] = tempb;
                                    G[y] = tempg;
                                    R[y] = tempr;
                                }
                            }
                        }
                        if (tNumber < 0 || tNumber > 8) return null;
                        tNumber = (tNumber % 2 == 0 ? tNumber : tNumber - 1);
                        for (int m = 0; m < (int)(tNumber / 2); m++)
                        {
                            R[m] = 0;
                            G[m] = 0;
                            B[m] = 0;
                            R[8 - m] = 0;
                            G[8 - m] = 0;
                            B[8 - m] = 0;
                        }
                        temp[i * 4 + j * w * 4] = (byte)(B.Sum() / (9 - tNumber));
                        temp[i * 4 + 1 + j * w * 4] = (byte)(G.Sum() / (9 - tNumber));
                        temp[i * 4 + 2 + j * w * 4] = (byte)(R.Sum() / (9 - tNumber));
                    }
                }
                Stream sTemp = filterImage.PixelBuffer.AsStream();
                sTemp.Seek(0, SeekOrigin.Begin);
                sTemp.Write(temp, 0, w * 4 * h);
                return filterImage;
            }
            else
            {
                return null;
            }
        }