/// <summary>
/// 中值滤波
/// </summary>
/// <param name="r"></param>
/// <returns></returns>
public static Bitmap MedianFilter(this Bitmap source, int r)
{
var listR = new List <List <byte> >();
var listG = new List <List <byte> >();
var listB = new List <List <byte> >();
switch (source.Type)
{
case 1:
foreach (var i in source.IndexData)
{
listR.Add(i.Select(j => source.Paletta[j].rgbRed).ToList());
listG.Add(i.Select(j => source.Paletta[j].rgbGreen).ToList());
listB.Add(i.Select(j => source.Paletta[j].rgbBlue).ToList());
}
break;
case 2:
foreach (var i in source.RGBData)
{
listR.Add(i.Select(j => j.rgbtRed).ToList());
listG.Add(i.Select(j => j.rgbtGreen).ToList());
listB.Add(i.Select(j => j.rgbtBlue).ToList());
}
break;
case 3:
foreach (var i in source.RGBAData)
{
listR.Add(i.Select(j => j.rgbRed).ToList());
listG.Add(i.Select(j => j.rgbGreen).ToList());
listB.Add(i.Select(j => j.rgbBlue).ToList());
}
break;
default:
throw new Exception("不支持的图像类型");
}
// 对三通道进行中值滤波
listR = ApplyMedianFilter(listR, r).Select(i => i.ToList()).ToList();
listG = ApplyMedianFilter(listG, r).Select(i => i.ToList()).ToList();
listB = ApplyMedianFilter(listB, r).Select(i => i.ToList()).ToList();
if (!(source.Clone() is Bitmap bitmap))
{
return(null);
}
switch (bitmap.Type)
{
case 1:
var rgbs = listR.Select(
(elem1, index1) =>
elem1.Select((elem2, index2) =>
(
listR[index1][index2],
listG[index1][index2],
listB[index1][index2]
)).ToArray()
).ToArray();
(bitmap.IndexData, bitmap.Paletta) = PalettaExtension.RGBArrayToPaletta(rgbs);
break;
case 2:
bitmap.RGBData = listR.Select(
(elem1, index1) =>
elem1.Select((elem2, index2) =>
new RGBTriple
{
rgbtRed = listR[index1][index2],
rgbtGreen = listG[index1][index2],
rgbtBlue = listB[index1][index2]
}).ToArray()
).ToArray();
break;
case 3:
bitmap.RGBAData = listR.Select(
(elem1, index1) =>
elem1.Select((elem2, index2) =>
new RGBQuad
{
rgbRed = listR[index1][index2],
rgbGreen = listG[index1][index2],
rgbBlue = listB[index1][index2]
}).ToArray()
).ToArray();
break;
default:
throw new Exception("不支持的图像类型");
}
return(bitmap);
}
/// <summary>
/// 添加椒盐噪声
/// </summary>
/// <param name="source"></param>
/// <param name="n">数量</param>
/// <returns></returns>
public static Bitmap AddSaltNoise(this Bitmap source, int n)
{
var listR = new List <List <byte> >();
var listG = new List <List <byte> >();
var listB = new List <List <byte> >();
switch (source.Type)
{
case 1:
foreach (var i in source.IndexData)
{
listR.Add(i.Select(j => source.Paletta[j].rgbRed).ToList());
listG.Add(i.Select(j => source.Paletta[j].rgbGreen).ToList());
listB.Add(i.Select(j => source.Paletta[j].rgbBlue).ToList());
}
break;
case 2:
foreach (var i in source.RGBData)
{
listR.Add(i.Select(j => j.rgbtRed).ToList());
listG.Add(i.Select(j => j.rgbtGreen).ToList());
listB.Add(i.Select(j => j.rgbtBlue).ToList());
}
break;
case 3:
foreach (var i in source.RGBAData)
{
listR.Add(i.Select(j => j.rgbRed).ToList());
listG.Add(i.Select(j => j.rgbGreen).ToList());
listB.Add(i.Select(j => j.rgbBlue).ToList());
}
break;
default:
throw new Exception("不支持的图像类型");
}
var bitmap = source.Clone() as Bitmap;
List <List <byte> > AddSalt(List <List <byte> > img)
{
var rand = new Random();
var height = img.Count;
var width = img[0].Count;
var dstImage = new byte[height][];
for (var i = 0; i < dstImage.Length; i++)
{
dstImage[i] = img[i].ToArray();
}
for (int k = 0; k < n; k++)
{
int i = rand.Next() % height;
int j = rand.Next() % width;
dstImage[i][j] = 255;
}
for (int k = 0; k < n; k++)
{
int i = rand.Next() % height;
int j = rand.Next() % width;
dstImage[i][j] = 0;
}
return(dstImage.Select(i => i.ToList()).ToList());
}
listR = AddSalt(listR);
if (!source.IsGray)
{
listB = AddSalt(listB);
listG = AddSalt(listG);
}
switch (source.Type)
{
case 1:
var rgbs = listR.Select(
(elem1, index1) =>
elem1.Select((elem2, index2) =>
(
listR[index1][index2],
source.IsGray ? listR[index1][index2] : listG[index1][index2],
source.IsGray ? listR[index1][index2] : listB[index1][index2]
)).ToArray()
).ToArray();
(bitmap.IndexData, bitmap.Paletta) = PalettaExtension.RGBArrayToPaletta(rgbs);
break;
case 2:
bitmap.RGBData = listR.Select(
(elem1, index1) =>
elem1.Select((elem2, index2) =>
new RGBTriple
{
rgbtRed = listR[index1][index2],
rgbtGreen = source.IsGray ? listR[index1][index2] : listG[index1][index2],
rgbtBlue = source.IsGray ? listR[index1][index2] : listB[index1][index2]
}).ToArray()
).ToArray();
break;
case 3:
bitmap.RGBAData = listR.Select(
(elem1, index1) =>
elem1.Select((elem2, index2) =>
new RGBQuad
{
rgbRed = listR[index1][index2],
rgbGreen = source.IsGray ? listR[index1][index2] : listG[index1][index2],
rgbBlue = source.IsGray ? listR[index1][index2] : listB[index1][index2]
}).ToArray()
).ToArray();
break;
default:
throw new Exception("不支持的图像类型");
}
return(bitmap);
}