Application: gvSIG desktop » gvSIG tools: ToolBox

package es.unex.sextante.imageAnalysis.contrastStretching;

import java.awt.image.DataBuffer;

import es.unex.sextante.additionalInfo.AdditionalInfoNumericalValue;

import es.unex.sextante.core.Sextante;

import es.unex.sextante.exceptions.GeoAlgorithmExecutionException;

import es.unex.sextante.exceptions.RepeatedParameterNameException;

import es.unex.sextante.imageAnalysis.pixelOpsBase.PixelOpsBaseAlgorithm;

public class ContrastStretchingAlgorithm

         extends

            PixelOpsBaseAlgorithm {

   public static final String LOWER = "LOWER";

   public static final String UPPER = "UPPER";

   private int                m_iUpper, m_iLower;

   private int[]              m_Histogram;

   private int                m_iSize;

   private double             m_dUpper, m_dLower;

   private double             m_dRange;

   @Override

   public void defineCharacteristics() {

      super.defineCharacteristics();

      setName(Sextante.getText("Contrast_stretching"));

      try {

         m_Parameters.addNumericalValue(LOWER, Sextante.getText("Lower_percentile"),

                  AdditionalInfoNumericalValue.NUMERICAL_VALUE_INTEGER, 0, 0, 99);

         m_Parameters.addNumericalValue(UPPER, Sextante.getText("Upper_percentile"),

                  AdditionalInfoNumericalValue.NUMERICAL_VALUE_INTEGER, 100, 1, 100);

      }

      catch (final RepeatedParameterNameException e) {

         Sextante.addErrorToLog(e);

      }

   }

   @Override

   protected void setValues() throws GeoAlgorithmExecutionException {

      super.setValues();

      m_Histogram = m_Image.getAccumulatedHistogram();

      final double dMin = m_dLower = m_Image.getMinValue();

      final double dMax = m_dUpper = m_Image.getMaxValue();

      final double dRange = dMax - dMin;

      m_iLower = m_Parameters.getParameterValueAsInt(LOWER);

      m_iUpper = m_Parameters.getParameterValueAsInt(UPPER);

      if (m_iLower > m_iUpper) {

         final int iSwap = m_iUpper;

         m_iUpper = m_iLower;

         m_iLower = iSwap;

      }

      m_iSize = (int) (Math.pow(2., DataBuffer.getDataTypeSize(m_Image.getDataType())) / 2.) - 1;

      m_iLower = (int) (m_Histogram[m_Histogram.length - 1] * (double) m_iLower / 100.);

      m_iUpper = (int) (m_Histogram[m_Histogram.length - 1] * (double) m_iUpper / 100.);

      for (int i = 0; i < m_Histogram.length - 1; i++) {

         if ((m_Histogram[i] < m_iLower) && (m_Histogram[i + 1] > m_iLower)) {

            m_dLower = dMin + (i + 1) * dRange / m_iSize;

         }

         if ((m_Histogram[i] < m_iUpper) && (m_Histogram[i + 1] > m_iUpper)) {

            m_dUpper = dMin + (i + 1) * dRange / m_iSize;

         }

      }

      m_dRange = m_dUpper - m_dLower;

   }

   @Override

   protected double getValueAt(final int x,

                               final int y) {

      final double dValue = m_Image.getCellValueAsDouble(x, y);

      double dRet = (dValue - m_dLower) / m_dRange * m_iSize;

      if (dRet > m_iSize) {

         dRet = m_iSize;

      }

      if (dRet < 0) {

         dRet = 0;

      }

      return dRet;

   }

}