我想在图像上放置锐化滤镜。我找到了一个网站有简短的教程。 我尝试用 C# 来做，所以这是我的代码。无论如何，我试图找出它不起作用的原因。我不知道我是否做错了什么，如果是，请告诉我该怎么做才能使其正常工作。谢谢
public static Bitmap sharpen(Bitmap image)
{
Bitmap sharpenImage = new Bitmap(image.Width, image.Height);
int filterWidth = 3;
int filterHeight = 3;
int w = image.Width;
int h = image.Height;
double[,] filter = new double[filterWidth, filterHeight];
filter[0, 0] = filter[0, 1] = filter[0, 2] = filter[1, 0] = filter[1, 2] = filter[2, 0] = filter[2, 1] = filter[2, 2] = -1;
filter[1, 1] = 9;
double factor = 1.0;
double bias = 0.0;
Color[,] result = new Color[image.Width, image.Height];
for (int x = 0; x < w; ++x)
{
for (int y = 0; y < h; ++y)
{
double red = 0.0, green = 0.0, blue = 0.0;
Color imageColor = image.GetPixel(x, y);
for (int filterX = 0; filterX < filterWidth; filterX++)
{
for (int filterY = 0; filterY < filterHeight; filterY++)
{
int imageX = (x - filterWidth / 2 + filterX + w) % w;
int imageY = (y - filterHeight / 2 + filterY + h) % h;
red += imageColor.R * filter[filterX, filterY];
green += imageColor.G * filter[filterX, filterY];
blue += imageColor.B * filter[filterX, filterY];
}
int r = Math.Min(Math.Max((int)(factor * red + bias), 0), 255);
int g = Math.Min(Math.Max((int)(factor * green + bias), 0), 255);
int b = Math.Min(Math.Max((int)(factor * blue + bias), 0), 255);
result[x, y] = Color.FromArgb(r, g, b);
}
}
}
for (int i = 0; i < w; ++i)
{
for (int j = 0; j < h; ++j)
{
sharpenImage.SetPixel(i, j, result[i, j]);
}
}
return sharpenImage;
}
我采用了 Daniel 的答案并通过使用 BitmapData 类对其进行了性能修改，因为使用 GetPixel/SetPixel 非常昂贵且不适合性能要求较高的系统。它的工作原理与之前的解决方案完全相同，可以替代使用。
public static Bitmap Sharpen(Bitmap image)
{
Bitmap sharpenImage = (Bitmap)image.Clone();
int filterWidth = 3;
int filterHeight = 3;
int width = image.Width;
int height = image.Height;
// Create sharpening filter.
double[,] filter = new double[filterWidth, filterHeight];
filter[0, 0] = filter[0, 1] = filter[0, 2] = filter[1, 0] = filter[1, 2] = filter[2, 0] = filter[2, 1] = filter[2, 2] = -1;
filter[1, 1] = 9;
double factor = 1.0;
double bias = 0.0;
Color[,] result = new Color[image.Width, image.Height];
// Lock image bits for read/write.
BitmapData pbits = sharpenImage.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
// Declare an array to hold the bytes of the bitmap.
int bytes = pbits.Stride * height;
byte[] rgbValues = new byte[bytes];
// Copy the RGB values into the array.
System.Runtime.InteropServices.Marshal.Copy(pbits.Scan0, rgbValues, 0, bytes);
int rgb;
// Fill the color array with the new sharpened color values.
for (int x = 0; x < width; ++x)
{
for (int y = 0; y < height; ++y)
{
double red = 0.0, green = 0.0, blue = 0.0;
for (int filterX = 0; filterX < filterWidth; filterX++)
{
for (int filterY = 0; filterY < filterHeight; filterY++)
{
int imageX = (x - filterWidth / 2 + filterX + width) % width;
int imageY = (y - filterHeight / 2 + filterY + height) % height;
rgb = imageY * pbits.Stride + 3 * imageX;
red += rgbValues[rgb + 2] * filter[filterX, filterY];
green += rgbValues[rgb + 1] * filter[filterX, filterY];
blue += rgbValues[rgb + 0] * filter[filterX, filterY];
}
int r = Math.Min(Math.Max((int)(factor * red + bias), 0), 255);
int g = Math.Min(Math.Max((int)(factor * green + bias), 0), 255);
int b = Math.Min(Math.Max((int)(factor * blue + bias), 0), 255);
result[x, y] = Color.FromArgb(r, g, b);
}
}
}
// Update the image with the sharpened pixels.
for (int x = 0; x < width; ++x)
{
for (int y = 0; y < height; ++y)
{
rgb = y * pbits.Stride + 3 * x;
rgbValues[rgb + 2] = result[x, y].R;
rgbValues[rgb + 1] = result[x, y].G;
rgbValues[rgb + 0] = result[x, y].B;
}
}
// Copy the RGB values back to the bitmap.
System.Runtime.InteropServices.Marshal.Copy(rgbValues, 0, pbits.Scan0, bytes);
// Release image bits.
sharpenImage.UnlockBits(pbits);
return sharpenImage;
}
public static Bitmap sharpen(Bitmap image)
{
Bitmap sharpenImage = new Bitmap(image.Width, image.Height);
int filterWidth = 3;
int filterHeight = 3;
int w = image.Width;
int h = image.Height;
double[,] filter = new double[filterWidth, filterHeight];
filter[0, 0] = filter[0, 1] = filter[0, 2] = filter[1, 0] = filter[1, 2] = filter[2, 0] = filter[2, 1] = filter[2, 2] = -1;
filter[1, 1] = 9;
double factor = 1.0;
double bias = 0.0;
Color[,] result = new Color[image.Width, image.Height];
for (int x = 0; x < w; ++x)
{
for (int y = 0; y < h; ++y)
{
double red = 0.0, green = 0.0, blue = 0.0;
//=====[REMOVE LINES]========================================================
// Color must be read per filter entry, not per image pixel.
Color imageColor = image.GetPixel(x, y);
//===========================================================================
for (int filterX = 0; filterX < filterWidth; filterX++)
{
for (int filterY = 0; filterY < filterHeight; filterY++)
{
int imageX = (x - filterWidth / 2 + filterX + w) % w;
int imageY = (y - filterHeight / 2 + filterY + h) % h;
//=====[INSERT LINES]========================================================
// Get the color here - once per fiter entry and image pixel.
Color imageColor = image.GetPixel(imageX, imageY);
//===========================================================================
red += imageColor.R * filter[filterX, filterY];
green += imageColor.G * filter[filterX, filterY];
blue += imageColor.B * filter[filterX, filterY];
}
int r = Math.Min(Math.Max((int)(factor * red + bias), 0), 255);
int g = Math.Min(Math.Max((int)(factor * green + bias), 0), 255);
int b = Math.Min(Math.Max((int)(factor * blue + bias), 0), 255);
result[x, y] = Color.FromArgb(r, g, b);
}
}
}
for (int i = 0; i < w; ++i)
{
for (int j = 0; j < h; ++j)
{
sharpenImage.SetPixel(i, j, result[i, j]);
}
}
return sharpenImage;
}
这将产生更柔和的锐化效果。如果需要，您可以扩展过滤器阵列，或者将 16 更改为更大的值，但我发现这并不像您拥有的那么严酷。
const int filterWidth = 5;
const int filterHeight = 5;
double[,] filter = new double[filterWidth,filterHeight] {
{ -1, -1, -1, -1, -1 },
{ -1, 2, 2, 2, -1 },
{ -1, 2, 16, 2, -1 },
{ -1, 2, 2, 2, -1 },
{ -1, -1, -1, -1, -1 }
};
double factor = 1.0 / 16.0;
我结合了 g45rg34d 和 David 的答案并修复了“偏差”属性。现在您可以将 0.0 到 1.0 之间的“强度”传递给 Sharpen() 函数。
/// <summary>
/// Sharpens the specified image.
/// </summary>
/// <param name="image">The image.</param>
/// <param name="strength">The strength between 0.0 and 1.0.</param>
/// <returns></returns>
public static Bitmap Sharpen(Image image, double strength)
{
using (var bitmap = image as Bitmap)
{
if (bitmap != null)
{
var sharpenImage = bitmap.Clone() as Bitmap;
int width = image.Width;
int height = image.Height;
// Create sharpening filter.
const int filterWidth = 5;
const int filterHeight = 5;
var filter = new double[,]
{
{-1, -1, -1, -1, -1},
{-1, 2, 2, 2, -1},
{-1, 2, 16, 2, -1},
{-1, 2, 2, 2, -1},
{-1, -1, -1, -1, -1}
};
double bias = 1.0 - strength;
double factor = strength/16.0;
var result = new Color[image.Width,image.Height];
// Lock image bits for read/write.
if (sharpenImage != null)
{
BitmapData pbits = sharpenImage.LockBits(new Rectangle(0, 0, width, height),
ImageLockMode.ReadWrite,
PixelFormat.Format24bppRgb);
// Declare an array to hold the bytes of the bitmap.
int bytes = pbits.Stride*height;
var rgbValues = new byte[bytes];
// Copy the RGB values into the array.
Marshal.Copy(pbits.Scan0, rgbValues, 0, bytes);
int rgb;
// Fill the color array with the new sharpened color values.
for (int x = 0; x < width; ++x)
{
for (int y = 0; y < height; ++y)
{
double red = 0.0, green = 0.0, blue = 0.0;
for (int filterX = 0; filterX < filterWidth; filterX++)
{
for (int filterY = 0; filterY < filterHeight; filterY++)
{
int imageX = (x - filterWidth/2 + filterX + width)%width;
int imageY = (y - filterHeight/2 + filterY + height)%height;
rgb = imageY*pbits.Stride + 3*imageX;
red += rgbValues[rgb + 2]*filter[filterX, filterY];
green += rgbValues[rgb + 1]*filter[filterX, filterY];
blue += rgbValues[rgb + 0]*filter[filterX, filterY];
}
rgb = y*pbits.Stride + 3*x;
int r = Math.Min(Math.Max((int) (factor*red + (bias*rgbValues[rgb + 2])), 0), 255);
int g = Math.Min(Math.Max((int) (factor*green + (bias*rgbValues[rgb + 1])), 0), 255);
int b = Math.Min(Math.Max((int) (factor*blue + (bias*rgbValues[rgb + 0])), 0), 255);
result[x, y] = Color.FromArgb(r, g, b);
}
}
}
// Update the image with the sharpened pixels.
for (int x = 0; x < width; ++x)
{
for (int y = 0; y < height; ++y)
{
rgb = y*pbits.Stride + 3*x;
rgbValues[rgb + 2] = result[x, y].R;
rgbValues[rgb + 1] = result[x, y].G;
rgbValues[rgb + 0] = result[x, y].B;
}
}
// Copy the RGB values back to the bitmap.
Marshal.Copy(rgbValues, 0, pbits.Scan0, bytes);
// Release image bits.
sharpenImage.UnlockBits(pbits);
}
return sharpenImage;
}
}
return null;
}
好的，解决了边缘扭曲的问题。这是更新的：
/// <summary>
/// Sharpens the specified image.
/// </summary>
/// <param name="image">The image.</param>
/// <param name="strength">The strength.</param>
/// <returns></returns>
public static Bitmap Sharpen(Image image, double strength)
{
using (var bitmap = image as Bitmap)
{
if (bitmap != null)
{
var sharpenImage = bitmap.Clone() as Bitmap;
int width = image.Width;
int height = image.Height;
// Create sharpening filter.
const int filterSize = 5;
var filter = new double[,]
{
{-1, -1, -1, -1, -1},
{-1, 2, 2, 2, -1},
{-1, 2, 16, 2, -1},
{-1, 2, 2, 2, -1},
{-1, -1, -1, -1, -1}
};
double bias = 1.0 - strength;
double factor = strength/16.0;
const int s = filterSize/2;
var result = new Color[image.Width,image.Height];
// Lock image bits for read/write.
if (sharpenImage != null)
{
BitmapData pbits = sharpenImage.LockBits(new Rectangle(0, 0, width, height),
ImageLockMode.ReadWrite,
PixelFormat.Format24bppRgb);
// Declare an array to hold the bytes of the bitmap.
int bytes = pbits.Stride*height;
var rgbValues = new byte[bytes];
// Copy the RGB values into the array.
Marshal.Copy(pbits.Scan0, rgbValues, 0, bytes);
int rgb;
// Fill the color array with the new sharpened color values.
for (int x = s; x < width - s; x++)
{
for (int y = s; y < height - s; y++)
{
double red = 0.0, green = 0.0, blue = 0.0;
for (int filterX = 0; filterX < filterSize; filterX++)
{
for (int filterY = 0; filterY < filterSize; filterY++)
{
int imageX = (x - s + filterX + width)%width;
int imageY = (y - s + filterY + height)%height;
rgb = imageY*pbits.Stride + 3*imageX;
red += rgbValues[rgb + 2]*filter[filterX, filterY];
green += rgbValues[rgb + 1]*filter[filterX, filterY];
blue += rgbValues[rgb + 0]*filter[filterX, filterY];
}
rgb = y * pbits.Stride + 3 * x;
int r = Math.Min(Math.Max((int)(factor * red + (bias * rgbValues[rgb + 2])), 0), 255);
int g = Math.Min(Math.Max((int)(factor * green + (bias * rgbValues[rgb + 1])), 0), 255);
int b = Math.Min(Math.Max((int)(factor * blue + (bias * rgbValues[rgb + 0])), 0), 255);
result[x, y] = Color.FromArgb(r, g, b);
}
}
}
// Update the image with the sharpened pixels.
for (int x = s; x < width - s; x++)
{
for (int y = s; y < height - s; y++)
{
rgb = y*pbits.Stride + 3*x;
rgbValues[rgb + 2] = result[x, y].R;
rgbValues[rgb + 1] = result[x, y].G;
rgbValues[rgb + 0] = result[x, y].B;
}
}
// Copy the RGB values back to the bitmap.
Marshal.Copy(rgbValues, 0, pbits.Scan0, bytes);
// Release image bits.
sharpenImage.UnlockBits(pbits);
}
return sharpenImage;
}
}
return null;
}
嗨，我稍微编辑了代码并添加了另外两个矩阵 对我来说这现在很完美
/// <summary>
/// Sharpens the specified image.
/// </summary>
/// <param name="image">The image.</param>
/// <param name="strength">strength erwartet werte zwische 0 - 99</param>
/// <returns></returns>
public Bitmap Sharpen(Image image, whichMatrix welcheMatrix , double strength)
{
double FaktorKorrekturWert = 0;
//strenght muß für den jeweiligen filter angepasst werden
switch (welcheMatrix)
{
case whichMatrix.Gaussian3x3:
//diese Matrix benötigt einen strenght Wert von 0 bis -9.9 default ist -2.5
//und einen korekturwert von 16
strength = (strength * -1) / 10;
FaktorKorrekturWert = 16;
break;
case whichMatrix.Mean3x3:
//diese Matrix benötigt einen strenght Wert von 0 bis -9 default ist -2.25
//und einen Korrekturwert von 10
strength = strength * -9 / 100;
FaktorKorrekturWert = 10;
break;
case whichMatrix.Gaussian5x5Type1:
//diese Matrix benötigt einen strenght Wert von 0 bis 2.5 default ist 1.25
//und einen Korrekturwert von 12
strength = strength * 2.5 / 100;
FaktorKorrekturWert = 12;
break;
default:
break;
}
using (var bitmap = image as Bitmap)
{
if (bitmap != null)
{
var sharpenImage = bitmap.Clone() as Bitmap;
int width = image.Width;
int height = image.Height;
// Create sharpening filter.
var filter = Matrix(welcheMatrix);
//const int filterSize = 3; // wenn die Matrix 3 Zeilen und 3 Spalten besitzt dann 3 bei 4 = 4 usw.
int filterSize = filter.GetLength(0);
double bias = 1.0 - strength;
double factor = strength / FaktorKorrekturWert;
//const int s = filterSize / 2;
int s = filterSize / 2; // Filtersize ist keine Constante mehr darum wurde der befehl const entfernt
var result = new Color[image.Width, image.Height];
// Lock image bits for read/write.
if (sharpenImage != null)
{
BitmapData pbits = sharpenImage.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
// Declare an array to hold the bytes of the bitmap.
int bytes = pbits.Stride * height;
var rgbValues = new byte[bytes];
// Copy the RGB values into the array.
Marshal.Copy(pbits.Scan0, rgbValues, 0, bytes);
int rgb;
// Fill the color array with the new sharpened color values.
for (int x = s; x < width - s; x++)
{
for (int y = s; y < height - s; y++)
{
double red = 0.0, green = 0.0, blue = 0.0;
for (int filterX = 0; filterX < filterSize; filterX++)
{
for (int filterY = 0; filterY < filterSize; filterY++)
{
int imageX = (x - s + filterX + width) % width;
int imageY = (y - s + filterY + height) % height;
rgb = imageY * pbits.Stride + 3 * imageX;
red += rgbValues[rgb + 2] * filter[filterX, filterY];
green += rgbValues[rgb + 1] * filter[filterX, filterY];
blue += rgbValues[rgb + 0] * filter[filterX, filterY];
}
rgb = y * pbits.Stride + 3 * x;
int r = Math.Min(Math.Max((int)(factor * red + (bias * rgbValues[rgb + 2])), 0), 255);
int g = Math.Min(Math.Max((int)(factor * green + (bias * rgbValues[rgb + 1])), 0), 255);
int b = Math.Min(Math.Max((int)(factor * blue + (bias * rgbValues[rgb + 0])), 0), 255);
result[x, y] = System.Drawing.Color.FromArgb(r, g, b);
}
}
}
// Update the image with the sharpened pixels.
for (int x = s; x < width - s; x++)
{
for (int y = s; y < height - s; y++)
{
rgb = y * pbits.Stride + 3 * x;
rgbValues[rgb + 2] = result[x, y].R;
rgbValues[rgb + 1] = result[x, y].G;
rgbValues[rgb + 0] = result[x, y].B;
}
}
// Copy the RGB values back to the bitmap.
Marshal.Copy(rgbValues, 0, pbits.Scan0, bytes);
// Release image bits.
sharpenImage.UnlockBits(pbits);
}
return sharpenImage;
}
}
return null;
}
public enum whichMatrix
{
Gaussian3x3,
Mean3x3,
Gaussian5x5Type1
}
private double[,] Matrix(whichMatrix welcheMatrix)
{
double[,] selectedMatrix = null;
switch (welcheMatrix)
{
case whichMatrix.Gaussian3x3:
selectedMatrix = new double[,]
{
{ 1, 2, 1, },
{ 2, 4, 2, },
{ 1, 2, 1, },
};
break;
case whichMatrix.Gaussian5x5Type1:
selectedMatrix = new double[,]
{
{-1, -1, -1, -1, -1},
{-1, 2, 2, 2, -1},
{-1, 2, 16, 2, -1},
{-1, 2, -1, 2, -1},
{-1, -1, -1, -1, -1}
};
break;
case whichMatrix.Mean3x3:
selectedMatrix =new double[,]
{
{ 1, 1, 1, },
{ 1, 1, 1, },
{ 1, 1, 1, },
};
break;
}
return selectedMatrix;
}