Here you can find the source of histogram(BufferedImage bufferedImage)
public static int[][] histogram(BufferedImage bufferedImage)
//package com.java2s; /*//from w ww.j a va 2 s . co m * JBoss, Home of Professional Open Source. * Copyright 2011, Red Hat, Inc., and individual contributors * as indicated by the @author tags. See the copyright.txt file in the * distribution for a full listing of individual contributors. * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This software is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */ import java.awt.image.BufferedImage; import java.awt.image.WritableRaster; public class Main { public static int[][] histogram(BufferedImage bufferedImage) { int[][] histogram = new int[3][256]; WritableRaster raster = bufferedImage.getRaster(); int pixel[] = new int[4]; for (int y = 0; y < raster.getHeight(); y++) { for (int x = 0; x < raster.getWidth(); x++) { raster.getPixel(x, y, pixel); for (int i = 0; i < 3; i++) { histogram[i][pixel[i]]++; } } } return histogram; } }