[AlgorithmInfo("Stretch del contrasto", Category = "FEI")]
  public class ContrastStretch : ImageOperation<Image<byte>, Image<byte>>
  {
    private int stretchDiscardPerc;

    [AlgorithmParameter]
    [DefaultValue(0)]
    public int StretchDiscardPercentage
    {
      get { return stretchDiscardPerc; }
      set
      {
        if (value < 0 || value > 100)
          throw new ArgumentOutOfRangeException("Inserire un valore fra 0 and 100.");
        stretchDiscardPerc = value;
      }
    }

    public ContrastStretch()
    {
    }

    public ContrastStretch(Image<byte> inputImage)
      : base(inputImage)
    {
      StretchDiscardPercentage = 0;
    }

    public ContrastStretch(Image<byte> inputImage, int stretchDiscard)
      : base(inputImage)
    {
      StretchDiscardPercentage = stretchDiscard;
    }

    public override void Run()
    {
      var hist = new BioLab.ImageProcessing.HistogramBuilder(InputImage).Execute();
      int nd = InputImage.PixelCount * StretchDiscardPercentage / 100;
      int i1 = 0;
      int sum = 0;
      while (sum < nd)
      {
        sum += hist[i1++];
      }
      int i2 = 255;
      sum = 0;
      while (sum < nd)
      {
        sum += hist[i2--];
      }
      int diff = i2 - i1;
      if (diff == 0)
        diff = 1;
      Result = new LookupTableTransform<byte>(InputImage,
                        p => ((p - i1) * 255 / diff).ClipToByte()).Execute();
    }
  }