[原创]中值滤波算法处理位图(C#实现)

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  1         //===================
  2         //作者：aaaSoft
  3         //日期：2009年12月11日
  4         //论坛：http://www.scbeta.com/bbs
  5         //说明：原创文章，转载请注明出处并保留作者信息
  6         //===================
  7
  8         /// <summary>
  9         /// 中值滤波算法处理
10         /// </summary>
11         /// <param name="bmp">原始图片</param>
12         /// <param name="bmp">是否是彩色位图</param>
13         /// <param name="windowRadius">过滤半径</param>
14         public Bitmap ColorfulBitmapMedianFilterFunction(Bitmap srcBmp, int windowRadius, bool IsColorfulBitmap)
15         {
16             if (windowRadius < 1)
17             {
18                 throw new Exception("过滤半径小于1没有意义");
19             }
20             //创建一个新的位图对象
21             Bitmap bmp = new Bitmap(srcBmp.Width, srcBmp.Height);
22
23             //存储该图片所有点的RGB值
24             byte[,] mR,mG,mB;
25             mR = new byte[srcBmp.Width, srcBmp.Height];
26             if (IsColorfulBitmap)
27             {
28                 mG = new byte[srcBmp.Width, srcBmp.Height];
29                 mB = new byte[srcBmp.Width, srcBmp.Height];
30             }
31             else
32             {
33                 mG = mR;
34                 mB = mR;
35             }
36
37             for (int i = 0; i <= srcBmp.Width - 1; i++)
38             {
39                 for (int j = 0; j <= srcBmp.Height - 1; j++)
40                 {
41                     mR[i, j] = srcBmp.GetPixel(i, j).R;
42                     if (IsColorfulBitmap)
43                     {
44                         mG[i, j] = srcBmp.GetPixel(i, j).G;
45                         mB[i, j] = srcBmp.GetPixel(i, j).B;
46                     }
47                 }
48             }
49
50             mR = MedianFilterFunction(mR, windowRadius);
51             if (IsColorfulBitmap)
52             {
53                 mG = MedianFilterFunction(mG, windowRadius);
54                 mB = MedianFilterFunction(mB, windowRadius);
55             }
56             else
57             {
58                 mG = mR;
59                 mB = mR;
60             }
61             for (int i = 0; i <= bmp.Width - 1; i++)
62             {
63                 for (int j = 0; j <= bmp.Height - 1; j++)
64                 {
65                     bmp.SetPixel(i, j, Color.FromArgb(mR[i, j], mG[i, j], mB[i, j]));
66                 }
67             }
68             return bmp;
69         }
70
71         /// <summary>
72         /// 对矩阵M进行中值滤波
73         /// </summary>
74         /// <param name="m">矩阵M</param>
75         /// <param name="windowRadius">过滤半径</param>
76         /// <returns>结果矩阵</returns>
77         private byte[,] MedianFilterFunction(byte[,] m, int windowRadius)
78         {
79             int width = m.GetLength(0);
80             int height = m.GetLength(1);
81
82             byte[,] lightArray = new byte[width, height];
83
84             //开始滤波
85             for (int i = 0; i <= width - 1; i++)
86             {
87                 for (int j = 0; j <= height - 1; j++)
88                 {
89                     //得到过滤窗口矩形
90                     Rectangle rectWindow = new Rectangle(i - windowRadius, j - windowRadius, 2 * windowRadius + 1, 2 * windowRadius + 1);
91                     if (rectWindow.Left < 0) rectWindow.X = 0;
92                     if (rectWindow.Top < 0) rectWindow.Y = 0;
93                     if (rectWindow.Right > width - 1) rectWindow.Width = width - 1 - rectWindow.Left;
94                     if (rectWindow.Bottom > height - 1) rectWindow.Height = height - 1 - rectWindow.Top;
95                     //将窗口中的颜色取到列表中
96                     List<byte> windowPixelColorList = new List<byte>();
97                     for (int oi = rectWindow.Left; oi <= rectWindow.Right - 1; oi++)
98                     {
99                         for (int oj = rectWindow.Top; oj <= rectWindow.Bottom - 1; oj++)
100                         {
101                             windowPixelColorList.Add(m[oi, oj]);
102                         }
103                     }
104                     //排序
105                     windowPixelColorList.Sort();
106                     //取中值
107                     byte middleValue = 0;
108                     if ((windowRadius * windowRadius) % 2 == 0)
109                     {
110                         //如果是偶数
111                         middleValue = Convert.ToByte((windowPixelColorList[windowPixelColorList.Count / 2] + windowPixelColorList[windowPixelColorList.Count / 2 - 1]) / 2);
112                     }
113                     else
114                     {
115                         //如果是奇数
116                         middleValue = windowPixelColorList[(windowPixelColorList.Count - 1) / 2];
117                     }
118                     //设置为中值
119                     lightArray[i, j] = middleValue;
120                 }
121             }
122             return lightArray;
123         }