以下例程仅用于增强8位索引的灰度。
此代码似乎对输入图像没有影响。就是说，正在进来的东西也一样。
如果我增加strength的值，图像似乎会变暗，但是永远不会过滤。
可能出什么问题了？
我正在使用以下内核，
double[,] _numericalKernel = new double[,]
{ { -1, -1, -1, },
{ -1, 9, -1, },
{ -1, -1, -1, }, };
以下是我的锐化源代码，
public static Bitmap NonfftSharpen(Bitmap image, double[,] mask, double strength)
{
Bitmap bitmap = (Bitmap)image.Clone();
if (bitmap != null)
{
int width = bitmap.Width;
int height = bitmap.Height;
if (mask.GetLength(0) != mask.GetLength(1))
{
throw new Exception("_numericalKernel dimensions must be same");
}
// Create sharpening filter.
int filterSize = mask.GetLength(0);
double[,] filter = (double[,])mask.Clone();
int channels = sizeof(byte);
double bias = 1.0 - strength;
double factor = strength / 16.0;
int halfOfFilerSize = filterSize / 2;
byte[,] result = new byte[bitmap.Width, bitmap.Height];
// Lock image bits for read/write.
BitmapData bitmapData = bitmap.LockBits(new Rectangle(0, 0, width, height),
ImageLockMode.ReadWrite,
PixelFormat.Format8bppIndexed);
// Declare an array to hold the bytes of the bitmap.
int memorySize = bitmapData.Stride * height;
byte[] memory = new byte[memorySize];
// Copy the RGB values into the local array.
Marshal.Copy(bitmapData.Scan0, memory, 0, memorySize);
int rgb;
// Fill the color array with the new sharpened color values.
for (int y = halfOfFilerSize; y < height - halfOfFilerSize; y++)
{
for (int x = halfOfFilerSize; x < width - halfOfFilerSize; x++)
{
for (int filterY = 0; filterY < filterSize; filterY++)
{
double grayShade = 0.0;
for (int filterX = 0; filterX < filterSize; filterX++)
{
int imageX = (x - halfOfFilerSize + filterX + width) % width;
int imageY = (y - halfOfFilerSize + filterY + height) % height;
rgb = imageY * bitmapData.Stride + channels * imageX;
grayShade += memory[rgb + 0] * filter[filterX, filterY];
}
rgb = y * bitmapData.Stride + channels * x;
int b = Math.Min(Math.Max((int)(factor * grayShade + (bias * memory[rgb + 0])), 0), 255);
result[x, y] = (byte)b;
}
}
}
// Update the image with the sharpened pixels.
for (int x = halfOfFilerSize; x < width - halfOfFilerSize; x++)
{
for (int y = halfOfFilerSize; y < height - halfOfFilerSize; y++)
{
rgb = y * bitmapData.Stride + channels * x;
memory[rgb + 0] = result[x, y];
}
}
// Copy the RGB values back to the bitmap.
Marshal.Copy(memory, 0, bitmapData.Scan0, memorySize);
// Release image bits.
bitmap.UnlockBits(bitmapData);
return bitmap;
}
else
{
throw new Exception("input image can't be null");
}
}
最佳答案
我对您的功能做了一些更改，以使其正常运行。
请注意，强度参数对我的功能没有影响。您可以使用bias和factor值来获得不同的亮度结果，依此类推。
public static Bitmap NonfftSharpen(Bitmap image, double[,] mask, double strength)
{
Bitmap bitmap = (Bitmap)image.Clone();
if (bitmap != null)
{
int width = bitmap.Width;
int height = bitmap.Height;
if (mask.GetLength(0) != mask.GetLength(1))
{
throw new Exception("_numericalKernel dimensions must be same");
}
// Create sharpening filter.
int filterSize = mask.GetLength(0);
double[,] filter = (double[,])mask.Clone();
int channels = sizeof(byte);
double bias = 0.0; // 1.0 - strength;
double factor = 1.0; // strength / 16.0;
byte[,] result = new byte[bitmap.Width, bitmap.Height];
// Lock image bits for read/write.
BitmapData bitmapData = bitmap.LockBits(new System.Drawing.Rectangle(0, 0, width, height),
ImageLockMode.ReadWrite,
System.Drawing.Imaging.PixelFormat.Format8bppIndexed);
// Declare an array to hold the bytes of the bitmap.
int memorySize = bitmapData.Stride * height;
byte[] memory = new byte[memorySize];
// Copy the RGB values into the local array.
Marshal.Copy(bitmapData.Scan0, memory, 0, memorySize);
int pixel;
// Fill the color array with the new sharpened color values.
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
double grayShade = 0.0;
for (int filterY = 0; filterY < filterSize; filterY++)
{
for (int filterX = 0; filterX < filterSize; filterX++)
{
int imageX = (x - filterSize / 2 + filterX + width) % width;
int imageY = (y - filterSize / 2 + filterY + height) % height;
pixel = imageY * bitmapData.Stride + channels * imageX;
grayShade += memory[pixel] * filter[filterX, filterY];
}
int newPixel = Math.Min(Math.Max((int)(factor * grayShade + bias), 0), 255);
result[x, y] = (byte)newPixel;
}
}
}
// Update the image with the sharpened pixels.
for (int x = 0; x < width; x++)
{
for (int y = 0; y < height; y++)
{
pixel = y * bitmapData.Stride + channels * x;
memory[pixel] = result[x, y];
}
}
// Copy the values back to the bitmap.
Marshal.Copy(memory, 0, bitmapData.Scan0, memorySize);
// Release image bits.
bitmap.UnlockBits(bitmapData);
return bitmap;
}
else
{
throw new Exception("input image can't be null");
}
}
我希望这可以帮助您:)
问候