/// <summary>
/// Initializes a new instance of the <see cref="Segment" /> class.
/// </summary>
/// <param name="numberOfBands">The number of bands.</param>
/// <param name="statistics">The statistics computed for the segment.</param>
/// <exception cref="System.ArgumentOutOfRangeException">The number of bands is less than 1.</exception>
public Segment(Int32 numberOfBands, SpectralStatistics statistics)
{
if (numberOfBands < 1)
{
throw new ArgumentOutOfRangeException(nameof(numberOfBands), "The number of bands is less than 1.");
}
Count = 0;
// initialize collections
_mean = new Double[numberOfBands];
if (statistics.HasFlag(SpectralStatistics.Variance))
{
_meanSquare = new Double[numberOfBands];
_variance = new Double[numberOfBands];
}
if (statistics.HasFlag(SpectralStatistics.Comoment))
{
_comoment = new Double[numberOfBands, numberOfBands];
}
if (statistics.HasFlag(SpectralStatistics.Covariance))
{
Covariance = new Double[numberOfBands, numberOfBands];
}
}
/// <summary>
/// Initializes a new instance of the <see cref="Segment" /> class.
/// </summary>
/// <param name="raster">The raster from which the segment is derived.</param>
/// <param name="statistics">The statistics computed for the segment.</param>
/// <exception cref="System.ArgumentNullException">The raster is null.</exception>
public Segment(IRaster raster, SpectralStatistics statistics)
{
if (raster == null)
{
throw new ArgumentNullException("raster", "The raster is null.");
}
Count = raster.NumberOfRows * raster.NumberOfColumns;
// mean computation
_mean = new Double[raster.NumberOfBands];
for (Int32 rowIndex = 0; rowIndex < raster.NumberOfRows; rowIndex++)
{
for (Int32 columnIndex = 0; columnIndex < raster.NumberOfColumns; columnIndex++)
{
for (Int32 bandIndex = 0; bandIndex < raster.NumberOfBands; bandIndex++)
{
_mean[bandIndex] += raster.GetFloatValue(rowIndex, columnIndex, bandIndex);
}
}
}
for (Int32 bandIndex = 0; bandIndex < raster.NumberOfBands; bandIndex++)
{
_mean[bandIndex] /= (raster.NumberOfColumns * raster.NumberOfRows);
}
// variance computation
if (statistics.HasFlag(SpectralStatistics.Variance) && raster.NumberOfColumns * raster.NumberOfRows > 1)
{
_meanSquare = new Double[raster.NumberOfBands];
_variance = new Double[raster.NumberOfBands];
for (Int32 rowIndex = 0; rowIndex < raster.NumberOfRows; rowIndex++)
{
for (Int32 columnIndex = 0; columnIndex < raster.NumberOfColumns; columnIndex++)
{
for (Int32 bandIndex = 0; bandIndex < raster.NumberOfBands; bandIndex++)
{
_variance[bandIndex] += Math.Pow(_mean[bandIndex] - raster.GetFloatValue(rowIndex, columnIndex, bandIndex), 2);
}
}
}
for (Int32 bandIndex = 0; bandIndex < raster.NumberOfBands; bandIndex++)
{
_meanSquare[bandIndex] = _mean[bandIndex] * _mean[bandIndex];
_variance[bandIndex] /= (raster.NumberOfColumns * raster.NumberOfRows - 1);
}
}
// comoment computation
if (statistics.HasFlag(SpectralStatistics.Comoment))
{
_comoment = new Double[raster.NumberOfBands, raster.NumberOfBands];
for (Int32 rowIndex = 0; rowIndex < raster.NumberOfRows; rowIndex++)
{
for (Int32 columnIndex = 0; columnIndex < raster.NumberOfColumns; columnIndex++)
{
for (Int32 bandIndex = 0; bandIndex < raster.NumberOfBands; bandIndex++)
{
for (Int32 otherBandIndex = 0; otherBandIndex < raster.NumberOfBands; otherBandIndex++)
{
_comoment[bandIndex, otherBandIndex] += (raster.GetFloatValue(rowIndex, columnIndex, bandIndex) - _mean[bandIndex]) * (raster.GetFloatValue(rowIndex, columnIndex, otherBandIndex) - _mean[otherBandIndex]);
}
}
}
}
}
// covariance computation
if (statistics.HasFlag(SpectralStatistics.Covariance) && raster.NumberOfColumns * raster.NumberOfRows > 1)
{
Covariance = new Double[raster.NumberOfBands, raster.NumberOfBands];
for (Int32 rowIndex = 0; rowIndex < raster.NumberOfRows; rowIndex++)
{
for (Int32 columnIndex = 0; columnIndex < raster.NumberOfColumns; columnIndex++)
{
for (Int32 bandIndex = 0; bandIndex < raster.NumberOfBands; bandIndex++)
{
for (Int32 otherBandIndex = 0; otherBandIndex < raster.NumberOfBands; otherBandIndex++)
{
Covariance[bandIndex, otherBandIndex] += (_mean[bandIndex] - raster.GetFloatValue(rowIndex, columnIndex, bandIndex)) * (_mean[otherBandIndex] - raster.GetFloatValue(rowIndex, columnIndex, otherBandIndex));
}
}
}
}
}
}
