001/**
002 * Copyright (c) 2011, The University of Southampton and the individual contributors.
003 * All rights reserved.
004 *
005 * Redistribution and use in source and binary forms, with or without modification,
006 * are permitted provided that the following conditions are met:
007 *
008 *   *  Redistributions of source code must retain the above copyright notice,
009 *      this list of conditions and the following disclaimer.
010 *
011 *   *  Redistributions in binary form must reproduce the above copyright notice,
012 *      this list of conditions and the following disclaimer in the documentation
013 *      and/or other materials provided with the distribution.
014 *
015 *   *  Neither the name of the University of Southampton nor the names of its
016 *      contributors may be used to endorse or promote products derived from this
017 *      software without specific prior written permission.
018 *
019 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
020 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
021 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
022 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
023 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
024 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
025 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
026 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
027 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
028 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
029 */
030package org.openimaj.image.processing.algorithm;
031
032import org.openimaj.image.FImage;
033import org.openimaj.image.processing.convolution.FGaussianConvolve;
034import org.openimaj.image.processor.ImageProcessor;
035
036/**
037 * Implementation of a difference of Gaussian filter.
038 * 
039 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
040 *
041 */
042public class DifferenceOfGaussian implements ImageProcessor<FImage> {
043        FGaussianConvolve filter1;
044        FGaussianConvolve filter2;
045        
046        /**
047         * Construct a difference of Gaussian with the default sigmas
048         * of 1 and 2.
049         */
050        public DifferenceOfGaussian() {
051                this(1, 2);
052        }
053        
054        /**
055         * Construct a difference of Gaussian with the specified 
056         * sigmas.
057         * @param sigma1 first (smaller sigma)
058         * @param sigma2 second sigma
059         */
060        public DifferenceOfGaussian(float sigma1, float sigma2) {
061                filter1 = new FGaussianConvolve(sigma1);
062                filter2 = new FGaussianConvolve(sigma2);
063        }
064        
065        /* (non-Javadoc)
066         * @see org.openimaj.image.processor.ImageProcessor#processImage(org.openimaj.image.Image)
067         */
068        @Override
069        public void processImage(FImage image) {
070                FImage blur1 = image.process(filter1);
071                FImage blur2 = image.process(filter2);
072                
073                image.internalAssign(blur1.subtractInplace(blur2));
074        }
075}