/**
    * Copyright (c) 2011, The University of Southampton and the individual contributors.
    * All rights reserved.
    *
    * Redistribution and use in source and binary forms, with or without modification,
    * are permitted provided that the following conditions are met:
    *
    *   * 	Redistributions of source code must retain the above copyright notice,
    * 	this list of conditions and the following disclaimer.
   *
   *   *	Redistributions in binary form must reproduce the above copyright notice,
   * 	this list of conditions and the following disclaimer in the documentation
   * 	and/or other materials provided with the distribution.
   *
   *   *	Neither the name of the University of Southampton nor the names of its
   * 	contributors may be used to endorse or promote products derived from this
   * 	software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
   * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
   * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  package org.openimaj.image.feature.global;
  
  import org.openimaj.citation.annotation.Reference;
  import org.openimaj.citation.annotation.ReferenceType;
  import org.openimaj.feature.DoubleFV;
  import org.openimaj.feature.FeatureVectorProvider;
  import org.openimaj.image.FImage;
  import org.openimaj.image.MBFImage;
  import org.openimaj.image.analyser.ImageAnalyser;
  import org.openimaj.image.mask.AbstractMaskedObject;
  
  /**
   * Estimate the saturation of an image using the RGB approximation of
   * avg(max(R,G,B) - min(R,G,B)).
   * 
   * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
   */
  @Reference(
  		type = ReferenceType.Inproceedings,
  		author = { "Jose San Pedro", "Stefan Siersdorfer" },
  		title = "Ranking and Classifying Attractiveness of Photos in Folksonomies",
  		year = "2009",
  		booktitle = "18th International World Wide Web Conference",
  		pages = { "771", "", "771" },
  		url = "http://www2009.eprints.org/78/",
  		month = "April")
  public class Saturation extends AbstractMaskedObject<FImage>
  		implements
  		ImageAnalyser<MBFImage>,
  		FeatureVectorProvider<DoubleFV>
  {
  	double saturation;
  
  	@Override
  	public DoubleFV getFeatureVector() {
  		return new DoubleFV(new double[] { saturation });
  	}
  
  	@Override
  	public void analyseImage(MBFImage image) {
  		final FImage R = image.getBand(0);
  		final FImage G = image.getBand(1);
  		final FImage B = image.getBand(2);
  
  		int N = 0;
  		double sat = 0;
  
  		if (mask != null) {
  			for (int y = 0; y < R.height; y++) {
  				for (int x = 0; x < R.width; x++) {
  					if (mask.pixels[y][x] == 1) {
  						final float min = Math.min(Math.min(R.pixels[y][x], G.pixels[y][x]), B.pixels[y][x]);
  						final float max = Math.max(Math.max(R.pixels[y][x], G.pixels[y][x]), B.pixels[y][x]);
  						sat += (max - min);
  						N++;
  					}
  				}
  			}
  		} else {
  			for (int y = 0; y < R.height; y++) {
  				for (int x = 0; x < R.width; x++) {
  					final float min = Math.min(Math.min(R.pixels[y][x], G.pixels[y][x]), B.pixels[y][x]);
  					final float max = Math.max(Math.max(R.pixels[y][x], G.pixels[y][x]), B.pixels[y][x]);
  					sat += (max - min);
  					N++;
  				}
  			}
  		}
  
  		saturation = sat / N;
 	}
 
 	/**
 	 * Get the average saturation of the last image processed with
 	 * {@link #analyseImage(MBFImage)}.
 	 * 
 	 * @return the saturation
 	 */
 	public double getSaturation() {
 		return saturation;
 	}
 }