/// <summary>
/// 画像に横方向のプリューウィットフィルタを適用
/// </summary>
/// <param name="sourceImage">画像の2次元配列</param>
/// <returns>フィルタ適用後の画像の2次元配列</returns>
public static double[,] ApplyHorizontalPrewittFilter(byte[,] sourceImage)
{
double[,] filter = new double[3, 3] {
{ -1.0 / 6.0, 0.0, 1.0 / 6.0 },
{ -1.0 / 6.0, 0.0, 1.0 / 6.0 },
{ -1.0 / 6.0, 0.0, 1.0 / 6.0 }
};
return(ImageFiltering.ApplyFilterAllowNegativeValues(sourceImage, filter));
}
/// <summary>
/// 画像に縦方向のソーベルフィルタを適用
/// </summary>
/// <param name="sourceImage">画像の2次元配列</param>
/// <returns>フィルタ適用後の画像の2次元配列</returns>
public static double[,] ApplyVerticalSobelFilter(byte[,] sourceImage)
{
double[,] filter = new double[3, 3] {
{ 1.0 / 8.0, 2.0 / 8.0, 1.0 / 8.0 },
{ 0.0, 0.0, 0.0 },
{ -1.0 / 8.0, -2.0 / 8.0, -1.0 / 8.0 }
};
return(ImageFiltering.ApplyFilterAllowNegativeValues(sourceImage, filter));
}
/// <summary>
/// 画像に縦方向の微分フィルタを適用
/// </summary>
/// <param name="sourceImage">画像の2次元配列</param>
/// <returns>フィルタ適用後の画像の2次元配列</returns>
public static double[,] ApplyVerticalDerivativeFilter(byte[,] sourceImage)
{
double[,] filter = new double[3, 3] {
{ 0.0, 0.5, 0.0 },
{ 0.0, 0.0, 0.0 },
{ 0.0, -0.5, 0.0 }
};
return(ImageFiltering.ApplyFilterAllowNegativeValues(sourceImage, filter));
}
/// <summary>
/// 画像にLoG(Laplacian of Gaussian)フィルタを適用
/// </summary>
/// <param name="sourceImage">画像の2次元配列</param>
/// <param name="filterSize">フィルタのサイズ</param>
/// <param name="standardDeviation">ガウス分布の標準偏差</param>
/// <returns>フィルタ適用後の画像の2次元配列</returns>
public static double[,] ApplyLoGFilter(byte[,] sourceImage, int filterSize, double standardDeviation)
{
Debug.Assert(filterSize % 2 == 1);
double[,] filter = new double[filterSize, filterSize];
for (int m = 0; m < filterSize; ++m)
{
for (int n = 0; n < filterSize; ++n)
{
double r = Math.Pow(m - (filterSize / 2), 2.0) + Math.Pow(n - (filterSize / 2), 2.0);
filter[m, n] = Math.Exp(-r / (2.0 * Math.Pow(standardDeviation, 2.0))) *
(r - 2.0 * Math.Pow(standardDeviation, 2.0)) /
(2.0 * Math.PI * Math.Pow(standardDeviation, 6.0));
}
}
return(ImageFiltering.ApplyFilterAllowNegativeValues(sourceImage, filter));
}
