/// <summary>
/// ヒストグラムの画像の作成
/// </summary>
/// <param name="sourceImage">画像の2次元配列</param>
/// <param name="histImageHeight">ヒストグラムの画像の高さ</param>
/// <returns>ヒストグラムの画像</returns>
public static byte[,] HistogramImage(byte[,] sourceImage, int histImageHeight)
{
int imageWidth = sourceImage.GetLength(0);
int imageHeight = sourceImage.GetLength(1);
int histImageWidth = 512;
int[] imageHist = ImageTransformation.Histogram(sourceImage);
int histMax = imageHist.Max();
byte[,] destImage = new byte[histImageWidth, histImageHeight];
imageHist = imageHist
.Select(histValue => histValue * histImageHeight / histMax)
.ToArray();
for (int x = 0; x < histImageWidth; ++x)
{
for (int y = 0; y < histImageHeight; ++y)
{
if (y < histImageHeight - imageHist[x / 2])
{
destImage[x, y] = 255;
}
else
{
destImage[x, y] = 0;
}
}
}
return(destImage);
}
/// <summary>
/// ヒストグラムの平坦化
/// </summary>
/// <param name="sourceImage">画像の2次元配列</param>
/// <returns>結果の画像の2次元配列</returns>
public static byte[,] HistogramEqualization(byte[,] sourceImage)
{
int imageWidth = sourceImage.GetLength(0);
int imageHeight = sourceImage.GetLength(1);
int imageSize = imageWidth * imageHeight;
byte[,] destImage = new byte[imageWidth, imageHeight];
int[] imageHist = ImageTransformation.Histogram(sourceImage);
for (int i = 1; i < imageHist.Length; ++i)
{
imageHist[i] = imageHist[i] + imageHist[i - 1];
}
byte[] conversionTable = imageHist
.Select(accumValue => accumValue * 255.0 / imageSize)
.Select(accumValue => (byte)Utility.Clamp(accumValue, byte.MinValue, byte.MaxValue))
.ToArray();
for (int x = 0; x < imageWidth; ++x)
{
for (int y = 0; y < imageHeight; ++y)
{
destImage[x, y] = conversionTable[sourceImage[x, y]];
}
}
return(destImage);
}