root / trunk / libraries / libRaster / src / org / gvsig / raster / util / Histogram.java @ 11072
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/* gvSIG. Sistema de Informaci?n Geogr?fica de la Generalitat Valenciana
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*
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* Copyright (C) 2007 IVER T.I. and Generalitat Valenciana.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,USA.
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*/
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package org.gvsig.raster.util; |
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/**
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* Representa un histograma.
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* @version 27/03/2007
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* @author Nacho Brodin (nachobrodin@gmail.com)
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*/
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public class Histogram { |
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private long[][] histogram = null; |
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private static String[] types = {"normal", "accumulated", "logaritmic"}; |
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/**
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* Constructor
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*/
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public Histogram() {
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histogram = new long[0][0]; |
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} |
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/**
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* Constructor. Inicializa valores a cero
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* @param bands N?mero de bandas
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* @param pxs N?mero de valores o clases
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*/
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public Histogram(int bands, int pxs) { |
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histogram = new long[bands][pxs]; |
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} |
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/**
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* Obtiene el histograma sin modificar
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* @return array bidimensional donde el primer elemento es el valor del pixel
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* o rango y el segundo el n?mero de elementos que aparecen.
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*/
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public long[][] getHistogram() { |
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return histogram;
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} |
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/**
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* Obtiene el n?mero de bandas del histograma
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* @return entero que representa el n?mero de bandas
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*/
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public int getNumBands() { |
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if(histogram != null) |
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return histogram.length;
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return 0; |
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} |
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/**
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* Obtiene la longitud (n?mero de valores) de una banda determinada
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* @param band Banda o obtener la longitud
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* @return entero con la longitud de la banda
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*/
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public int getBandLenght(int band) { |
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if(histogram != null) |
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return histogram[band].length;
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return 0; |
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} |
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/**
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* Obtiene el n?mero de valores o clases del histograma
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* @return entero que representa el n?mero de valores o clases del histograma
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*/
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public int getNumValues() { |
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if(histogram != null) |
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return histogram[0].length; |
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return 0; |
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} |
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/**
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* Asigna un histograma
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* @param hist histograma asignado
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*/
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public void setHistogram(long[][] hist){ |
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histogram = hist; |
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} |
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/**
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* ASigna un valor para una posici?n del histograma
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* @param bands Valor del pixel o clase a asignar
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* @param px Valor del pixel
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* @param value Valor a asignar
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*/
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public void setHistogramValue(int band, int px, long value) { |
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if(histogram != null) |
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histogram[band][px] = value; |
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} |
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/**
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* Obtiene un valor del histograma
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* @param band N?mero de banda del valor a recuperar
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* @param px Pixel o valor de la clase del valor a recuperar
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* @return valor
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*/
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public long getHistogramValue(int band, int px) { |
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return histogram[band][px];
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} |
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/**
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* Incrementa un valor de una posici?n del histograma
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* @param band N?mero de banda
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* @param px Pixel o valor de la clase
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*/
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public void incrementPxValue(int band, int px) { |
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histogram[band][px] ++; |
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} |
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/**
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* Devuelve el histograma acumulado
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* @return
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*/
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public long[][] getAccumulatedHistogram() { |
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if (histogram != null){ |
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long[][] hist = new long[histogram.length][histogram[0].length]; |
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for (int iBand = 0; iBand < hist.length; iBand++) { |
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hist[iBand][0] = histogram[iBand][0]; |
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for (int j = 1; j < hist[iBand].length; j++) { |
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hist[iBand][j] = hist[iBand][j - 1] + histogram[iBand][j];
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} |
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} |
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return hist;
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} |
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return null; |
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} |
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/**
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* Devuelve el histograma logaritmico
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* @return
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*/
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public long[][] getLogaritmicHistogram() { |
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if (histogram != null) { |
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long[][] hist = new long[histogram.length][histogram[0].length]; |
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long min = histogram[0][0]; |
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for (int iBand = 0; iBand < histogram.length; iBand++) |
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for (int j = 1; j < histogram[iBand].length; j++) |
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if (min > histogram[iBand][j]) min = histogram[iBand][j];
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for (int iBand = 0; iBand < histogram.length; iBand++) { |
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for (int j = 0; j < histogram[iBand].length; j++) |
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// Lo multiplico por 1000 para que no se pierdan datos al redondear
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hist[iBand][j] = (long) (1000.0 * java.lang.Math.log((double) (histogram[iBand][j] - min + 1))); |
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} |
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return hist;
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} |
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return null; |
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} |
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/**
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* N?mero de tipos de histograma definidos en esta clase.
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* @return entero con el n?mero de tipos definidos.
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*/
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public static int getHistogramTypesCount() { |
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return types.length;
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} |
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/**
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* Obtiene un tipo de histograma a partir de su posici?n en el array
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* @param pos posici?n en el array del tipo a obtener
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* @return Tipo
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*/
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public static String getType(int pos) { |
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return types[pos];
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} |
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/**
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* Obtiene el histograma correspondiente al tipo pasado por par?metro. Los tipos
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* est?n definidos en esta misma clase de forma est?tica en la variable types.
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* @param type Tipo a devolver
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* @return Histograma
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*/
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public long[][] getHistogramByType(String type) { |
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if(type.equals(types[0])) |
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return getHistogram();
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if(type.equals(types[1])) |
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return getAccumulatedHistogram();
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if(type.equals(types[2])) |
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return getLogaritmicHistogram();
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return null; |
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} |
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/**
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* Calculo de estad?sticas a partir de un histograma. El resultado de la funci?n es un array
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* bidimensional donde el primer ?ndice inndica la estadistica y el segundo el n?mero de banda.
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*
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* <UL>
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* <LI>m?nimo</LI>
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* <LI>m?ximo</LI>
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* <LI>media</LI>
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* <LI>mediana</LI>
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* <LI>N?mero de pixels</LI>
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* </UL>
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* @param histogram
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* @param bandas solicitadas. Cada elemento del vector representa una banda. Si est? a true se calcula la
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* estadistica para esa banda y si est? a false no se calcular?.
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* @return
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*/
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public long[][] getBasicStats(boolean[] bands) { |
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if(histogram == null) |
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return null; |
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return getBasicStats(0, histogram[0].length - 1, bands); |
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} |
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/**
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* Calculo de estad?sticas a partir de un histograma. El resultado de la funci?n es un array
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* bidimensional donde el primer ?ndice inndica la estadistica y el segundo el n?mero de banda.
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*
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* <UL>
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* <LI>m?nimo</LI>
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* <LI>m?ximo</LI>
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* <LI>media</LI>
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* <LI>mediana</LI>
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* <LI>N?mero de pixels</LI>
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* </UL>
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* @param histogram
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* @param beginPos Posici?n de inicio del histograma para contabilizar estadisticas
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* @param endPos Posici?n de fin del histograma para contabilizar estadisticas
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* @param bandas solicitadas. Cada elemento del vector representa una banda. Si est? a true se calcula la
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* estadistica para esa banda y si est? a false no se calcular?.
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* @return
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*/
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public long[][] getBasicStats(int beginPos, int endPos, boolean[] bands){ |
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if(histogram == null) |
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return null; |
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//Contamos el n?mero de bandas para las cuales se calcula la estad?stica
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int bandCount = 0; |
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for(int iBand = 0; iBand < bands.length; iBand ++) |
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if(bands[iBand])
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bandCount ++; |
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int values = 5; |
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long[][] res = new long[values][]; |
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long[] min = new long[bandCount];//M?nimo |
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long[] max = new long[bandCount];//M?ximo |
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for(int iBand = 0; iBand < bandCount; iBand ++){ |
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max[iBand] = beginPos; |
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min[iBand] = endPos; |
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} |
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long[] average = new long[bandCount]; //Valor de pixel medio (Media) |
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long[] middle = new long[bandCount]; //Mediana |
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long[] nPixelsBand = new long[bandCount];//N?mero de pixels por banda |
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int showBandCounter = 0; //Contador de bandas de las que hay calcular la estadistica |
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for(int iBand = 0; iBand < histogram.length; iBand ++){ |
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if(bands[iBand]){
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int pixels = 0; //N?mero de valores por banda (entre 0 y 255) |
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for(int i = beginPos; i <= endPos; i ++){ |
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//Calculo del m?nimo
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if(histogram[iBand][i] != 0 && i < min[showBandCounter]) |
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min[showBandCounter] = i; |
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//Calculo del m?ximo
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if(histogram[iBand][i] != 0 && i > max[showBandCounter]) |
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max[showBandCounter] = i; |
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//Calculo del n?mero de pixeles
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nPixelsBand[showBandCounter] += (long)histogram[iBand][i];
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if(histogram[iBand][i] != 0) |
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pixels ++; |
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average[showBandCounter] += histogram[iBand][i] * i; |
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} |
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//Calculo de la media
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try{
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average[showBandCounter] /= nPixelsBand[showBandCounter]; |
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}catch(ArithmeticException exc){ |
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average[showBandCounter] = 0;
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} |
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//Calculo de mediana
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long middlePos = nPixelsBand[showBandCounter] >> 1; |
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int aux = 0; |
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int i = beginPos;
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for(i = beginPos; aux < middlePos; i++)
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aux += histogram[iBand][i]; |
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middle[showBandCounter] = i - 1;
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showBandCounter ++; |
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} |
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} |
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res[0] = min;
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res[1] = max;
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res[2] = average;
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res[3] = middle;
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res[4] = nPixelsBand;
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return res;
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} |
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} |