/// <summary>
/// Prepares the result of the operation.
/// </summary>
/// <returns>The resulting object.</returns>
protected override ISpectralGeometry PrepareResult()
{
_offset = new Int32[Source.Raster.NumberOfBands];
_factor = new Double[Source.Raster.NumberOfBands];
for (Int32 bandIndex = 0; bandIndex < Source.Raster.NumberOfBands; bandIndex++)
{
Int32 minIntensity = 0, maxIntensity = Source.Raster.HistogramValues[bandIndex].Count - 1;
while (minIntensity < Source.Raster.HistogramValues[bandIndex].Count && Source.Raster.HistogramValues[bandIndex][minIntensity] == 0)
{
minIntensity++;
}
while (maxIntensity >= 0 && Source.Raster.HistogramValues[bandIndex][maxIntensity] == 0)
{
maxIntensity--;
}
if (minIntensity == maxIntensity)
{
_offset[bandIndex] = 0;
_factor[bandIndex] = 1;
}
else
{
_offset[bandIndex] = -minIntensity;
_factor[bandIndex] = (Double)RasterAlgorithms.RadiometricResolutionMax(Source.Raster.RadiometricResolution) / (maxIntensity - minIntensity);
}
}
return(base.PrepareResult());
}
/// <summary>
/// Computes the specified spectral value.
/// </summary>
/// <param name="rowIndex">The zero-based row index of the value.</param>
/// <param name="columnIndex">The zero-based column index of the value.</param>
/// <param name="bandIndex">The zero-based band index of the value.</param>
/// <returns>The spectral value at the specified index.</returns>
protected override UInt32 Compute(Int32 rowIndex, Int32 columnIndex, Int32 bandIndex)
{
if (_multipliers[bandIndex] == 0)
{
return(RasterAlgorithms.RadiometricResolutionMax(Source.Raster.RadiometricResolution) / 2 + 1);
}
return(RasterAlgorithms.Restrict(_multipliers[bandIndex] * Source.Raster.GetValue(rowIndex, columnIndex, bandIndex), Source.Raster.RadiometricResolution));
}
/// <summary>
/// Initializes a new instance of the <see cref="KMeansClustering"/> class.
/// </summary>
/// <param name="source">The source.</param>
/// <param name="target">The target.</param>
/// <param name="parameters">The parameters.</param>
/// <exception cref="System.ArgumentNullException">
/// The source is null.
/// or
/// The method is null.
/// or
/// The method requires parameters which are not specified.
/// </exception>
/// <exception cref="System.ArgumentException">
/// The parameters do not contain a required parameter value.
/// or
/// The type of a parameter does not match the type specified by the method.
/// or
/// The value of a parameter is not within the expected range.
/// or
/// The specified source and result are the same objects, but the method does not support in-place operations.
/// or
/// The source geometry does not contain raster data.
/// or
/// The raster format of the source is not supported by the method.
/// </exception>
public KMeansClustering(ISpectralGeometry source, ISpectralGeometry target, IDictionary<OperationParameter, Object> parameters)
: base(source, target, SpectralOperationMethods.KMeansClustering, parameters)
{
_numberOfClusters = Convert.ToInt32(ResolveParameter(SpectralOperationParameters.NumberOfClusters));
_maximumIterations = Convert.ToInt32(ResolveParameter(CommonOperationParameters.NumberOfIterations));
if (_numberOfClusters == 0)
_numberOfClusters = (Int32)(Math.Sqrt(Source.Raster.NumberOfRows * Source.Raster.NumberOfColumns) * Source.Raster.RadiometricResolution / 8);
if (_maximumIterations == 0)
_maximumIterations = _numberOfClusters;
_maximumDifference = RasterAlgorithms.RadiometricResolutionMax(Source.Raster) / Source.Raster.NumberOfRows * Source.Raster.NumberOfColumns;
}
/// <summary>
/// Computes the parameters of the specified band.
/// </summary>
/// <param name="bandIndex">The band index.</param>
private void ComputeParameters(Int32 bandIndex)
{
// source: http://en.wikipedia.org/wiki/Histogram_equalization
IReadOnlyList <Int32> histogram = Source.Raster.HistogramValues[bandIndex];
_cumulativeDistributionValues[bandIndex] = new Double[histogram.Count];
// setting values
_cumulativeDistributionValues[bandIndex][0] = Convert.ToDouble(histogram[0]) / (Source.Raster.NumberOfRows * Source.Raster.NumberOfColumns);
for (Int32 i = 1; i < histogram.Count; i++)
{
_cumulativeDistributionValues[bandIndex][i] = _cumulativeDistributionValues[bandIndex][i - 1] + Convert.ToDouble(histogram[i]) / (Source.Raster.NumberOfRows * Source.Raster.NumberOfColumns);
}
// setting minimum
Int32 minIndex = 0;
for (Int32 i = 0; i < histogram.Count; i++)
{
if (histogram[i] != 0)
{
minIndex = i;
break;
}
}
_cumulativeDistributionMinimums[bandIndex] = _cumulativeDistributionValues[bandIndex][minIndex];
// setting maximum
Int32 maxIndex = histogram.Count - 1;
for (Int32 i = histogram.Count - 1; i >= 0; i--)
{
if (histogram[i] != 0)
{
maxIndex = i;
break;
}
}
_cumulativeDistributionMaximums[bandIndex] = _cumulativeDistributionValues[bandIndex][maxIndex];
// exponent
_radiometricResolutionExponents[bandIndex] = Calculator.Pow(2, Source.Raster.RadiometricResolution);
// radiometric value limit
_radiometricValueLimits[bandIndex] = RasterAlgorithms.RadiometricResolutionMax(Source.Raster.RadiometricResolution);
}
/// <summary>
/// Computes the specified spectral value.
/// </summary>
/// <param name="rowIndex">The zero-based row index of the value.</param>
/// <param name="columnIndex">The zero-based column index of the value.</param>
/// <param name="bandIndex">The zero-based band index of the value.</param>
/// <returns>
/// The spectral value at the specified index.
/// </returns>
protected override UInt32 Compute(Int32 rowIndex, Int32 columnIndex, Int32 bandIndex)
{
Int32 rowCenter = (_structuringElement.NumberOfRows - 1) / 2;
Int32 columnCenter = (_structuringElement.NumberOfColumns - 1) / 2;
Int32 firstRowIndex = rowIndex - rowCenter;
Int32 firstColumnIndex = columnIndex - columnCenter;
Double result = RasterAlgorithms.RadiometricResolutionMax(Source.Raster.RadiometricResolution);
for (Int32 row = 0; row < _structuringElement.NumberOfRows; row++)
{
for (Int32 column = 0; column < _structuringElement.NumberOfColumns; column++)
{
Double value = Source.Raster.GetNearestValue(firstRowIndex + row, firstColumnIndex + column, bandIndex) - _structuringElement[row, column];
if (value >= 0 && value < result)
{
result = value;
}
}
}
return((UInt32)result);
}
/// <summary>
/// Asserts the results for the specified band.
/// </summary>
/// <param name="source">The source raster.</param>
/// <param name="sourceBandIndex">The band index of the source raster.</param>
/// <param name="result">The resulting raster.</param>
/// <param name="resultBandIndex">The band index of the resulting raster.</param>
private void AssertResultForBand(IRaster source, Int32 sourceBandIndex, IRaster result, Int32 resultBandIndex)
{
Assert.AreEqual(source.HistogramValues[sourceBandIndex].Sum(), result.HistogramValues[resultBandIndex].Sum());
Assert.Greater(result.HistogramValues[resultBandIndex][0], 0);
for (Int32 rowIndex = 0; rowIndex < result.NumberOfRows; rowIndex++)
{
for (Int32 columnIndex = 0; columnIndex < result.NumberOfColumns; columnIndex++)
{
Assert.GreaterOrEqual(result.GetValue(rowIndex, columnIndex, resultBandIndex), 0);
Assert.LessOrEqual(result.GetValue(rowIndex, columnIndex, resultBandIndex), RasterAlgorithms.RadiometricResolutionMax(source.RadiometricResolution));
}
}
}
/// <summary>
/// Prepares the result of the operation.
/// </summary>
/// <returns>The resulting object.</returns>
protected override ISpectralGeometry PrepareResult()
{
_peek = RasterAlgorithms.RadiometricResolutionMax(Source.Raster.RadiometricResolution);
return(base.PrepareResult());
}
