/**
 * 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.local.detector.dog.pyramid;

import java.lang.reflect.Array;

import org.openimaj.image.FImage;
import org.openimaj.image.Image;
import org.openimaj.image.analysis.pyramid.OctaveProcessor;
import org.openimaj.image.analysis.pyramid.gaussian.GaussianOctave;
import org.openimaj.image.analysis.pyramid.gaussian.GaussianPyramid;
import org.openimaj.image.processor.SinglebandImageProcessor;


/**
 * A DoGOctave is capable of processing an octave of Gaussian blurred
 * images to produce an octave of difference-of-Gaussian images.
 * 
 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
 * 
 * @param <I> The concrete {@link Image} subclass. 
 */
public class DoGOctave<
                I extends Image<?,I> & SinglebandImageProcessor.Processable<Float,FImage,I>> 
        extends 
                GaussianOctave<I> implements OctaveProcessor<GaussianOctave<I>, I> 
{ 
        /**
         * Construct a Difference of Gaussian octave with the provided parent Pyramid
         * and octaveSize. The octaveSize parameter is the size of 
         * the octave's images compared to the original image used
         * to construct the pyramid. An octaveSize of 1 means the 
         * same size as the original, 2 means half size, 4 means 
         * quarter size, etc.
         * 
         * @param parent the pyramid that this octave belongs to
         * @param octSize the size of the octave relative to
         *                      the original image.
         */
        public DoGOctave(GaussianPyramid<I> parent, float octSize) {
                super(parent, octSize);
        }
        
        @SuppressWarnings("unchecked")
        @Override
        public void process(GaussianOctave<I> octave) {
                images = (I[]) Array.newInstance(octave.images[0].getClass(), options.getScales() + options.getExtraScaleSteps());
                
                //compute DoG by subtracting adjacent levels 
                for (int i = 0; i < images.length; i++) {
                        images[i] = octave.images[i].clone();
                        images[i].subtractInplace(octave.images[i + 1]);
                }
        }
}