LIRe 源代码分析 3:基本接口(ImageSearcher)

上篇文章介绍了LIRe源代码里的DocumentBuilder的几个基本接口:

LIRe 源代码分析 2:基本接口(DocumentBuilder)

本文继续研究一下源代码里的ImageSearcher的几个基本接口。

下面来看看与ImageSearcher相关的类的定义:

ImageSearcher:接口,定义了基本的方法。

AbstractImageSearcher:纯虚类,实现了ImageSearcher接口。

ImageSearcherFactory:用于创建ImageSearcher。

ImageSearcher相关的类的继承关系如下图所示。可见,各种算法类都继承了AbstractImageSearcher,而AbstractImageSearcher实现了ImageSearcher接口。

LIRe 源代码分析 3:基本接口(ImageSearcher)

此外还有一个结构体:

ImageSearchHits:用于存储搜索的结果。


详细的源代码如下所示:

ImageSearcher

 

/*

 * This file is part of the LIRe project: http://www.semanticmetadata.net/lire

 * LIRe is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * LIRe 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with LIRe; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 * We kindly ask you to refer the following paper in any publication mentioning Lire:

 *

 * Lux Mathias, Savvas A. Chatzichristofis. Lire: Lucene Image Retrieval 鈥�

 * An Extensible Java CBIR Library. In proceedings of the 16th ACM International

 * Conference on Multimedia, pp. 1085-1088, Vancouver, Canada, 2008

 *

 * http://doi.acm.org/10.1145/1459359.1459577

 *

 * Copyright statement:

 * --------------------

 * (c) 2002-2011 by Mathias Lux ([email protected])

 *     http://www.semanticmetadata.net/lire

 */



package net.semanticmetadata.lire;



import org.apache.lucene.document.Document;

import org.apache.lucene.index.IndexReader;



import java.awt.image.BufferedImage;

import java.io.IOException;

import java.io.InputStream;

import java.util.Set;



/**

 * <h2>Searching in an Index</h2>

 * Use the ImageSearcherFactory for creating an ImageSearcher, which will retrieve the images

 * for you from the index.

 * <p/>

 * <pre>

 * IndexReader reader = IndexReader.open(indexPath);

 * ImageSearcher searcher = ImageSearcherFactory.createDefaultSearcher();

 * FileInputStream imageStream = new FileInputStream("image.jpg");

 * BufferedImage bimg = ImageIO.read(imageStream);

 * // searching for an image:

 * ImageSearchHits hits = null;

 * hits = searcher.search(bimg, reader);

 * for (int i = 0; i < 5; i++) {

 * System.out.println(hits.score(i) + ": " + hits.doc(i).getField(DocumentBuilder.FIELD_NAME_IDENTIFIER).stringValue());

 * }

 *

 * // searching for a document:

 * Document document = hits.doc(0);

 * hits = searcher.search(document, reader);

 * for (int i = 0; i < 5; i++) {

 * System.out.println(hits.score(i) + ": " + hits.doc(i).getField(DocumentBuilder.FIELD_NAME_IDENTIFIER).stringValue());

 * }

 * </pre>

 * <p/>

 * This file is part of the Caliph and Emir project: http://www.SemanticMetadata.net

 * <br>Date: 01.02.2006

 * <br>Time: 00:09:42

 *

 * @author Mathias Lux, [email protected]

 */

public interface ImageSearcher {

    /**

     * Searches for images similar to the given image.

     *

     * @param image  the example image to search for.

     * @param reader the IndexReader which is used to dsearch through the images.

     * @return a sorted list of hits.

     * @throws java.io.IOException in case exceptions in the reader occurs

     */

    public ImageSearchHits search(BufferedImage image, IndexReader reader) throws IOException;



    /**

     * Searches for images similar to the given image, defined by the Document from the index.

     *

     * @param doc    the example image to search for.

     * @param reader the IndexReader which is used to dsearch through the images.

     * @return a sorted list of hits.

     * @throws java.io.IOException in case exceptions in the reader occurs

     */

    public ImageSearchHits search(Document doc, IndexReader reader) throws IOException;



    /**

     * Searches for images similar to the given image.

     *

     * @param image  the example image to search for.

     * @param reader the IndexReader which is used to dsearch through the images.

     * @return a sorted list of hits.

     * @throws IOException in case the image could not be read from stream.

     */

    public ImageSearchHits search(InputStream image, IndexReader reader) throws IOException;



    /**

     * Identifies duplicates in the database.

     *

     * @param reader the IndexReader which is used to dsearch through the images.

     * @return a sorted list of hits.

     * @throws IOException in case the image could not be read from stream.

     */

    public ImageDuplicates findDuplicates(IndexReader reader) throws IOException;



    /**

     * Modifies the given search by the provided positive and negative examples. This process follows the idea

     * of relevance feedback.

     *

     * @param originalSearch

     * @param positives

     * @param negatives

     * @return

     */

    public ImageSearchHits relevanceFeedback(ImageSearchHits originalSearch,

                                             Set<Document> positives, Set<Document> negatives);

}


从接口的源代码可以看出,提供了5个方法,其中有3个名字都叫search(),只是参数不一样。一个是BufferedImage,一个是Document,而另一个是InputStream。

 

AbstractImageSearcher

 

/*

 * This file is part of the LIRe project: http://www.semanticmetadata.net/lire

 * LIRe is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * LIRe 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with LIRe; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 * We kindly ask you to refer the following paper in any publication mentioning Lire:

 *

 * Lux Mathias, Savvas A. Chatzichristofis. Lire: Lucene Image Retrieval 鈥�

 * An Extensible Java CBIR Library. In proceedings of the 16th ACM International

 * Conference on Multimedia, pp. 1085-1088, Vancouver, Canada, 2008

 *

 * http://doi.acm.org/10.1145/1459359.1459577

 *

 * Copyright statement:

 * --------------------

 * (c) 2002-2011 by Mathias Lux ([email protected])

 *     http://www.semanticmetadata.net/lire

 */

package net.semanticmetadata.lire;



import org.apache.lucene.document.Document;

import org.apache.lucene.index.IndexReader;



import javax.imageio.ImageIO;

import java.awt.image.BufferedImage;

import java.io.IOException;

import java.io.InputStream;

import java.util.Set;





/**

 * Abstract ImageSearcher, which uses javax.imageio.ImageIO to create a BufferedImage

 * from an InputStream.

 * <p/>

 * This file is part of the Caliph and Emir project: http://www.SemanticMetadata.net

 * <br>Date: 01.02.2006

 * <br>Time: 00:13:16

 *

 * @author Mathias Lux, [email protected]

 */

public abstract class AbstractImageSearcher implements ImageSearcher {

    /**

     * Searches for images similar to the given image. This simple implementation uses

     * {@link ImageSearcher#search(java.awt.image.BufferedImage, org.apache.lucene.index.IndexReader)},

     * the image is read using javax.imageio.ImageIO.

     *

     * @param image  the example image to search for.

     * @param reader the IndexReader which is used to dsearch through the images.

     * @return a sorted list of hits.

     * @throws IOException in case the image could not be read from stream.

     */

    public ImageSearchHits search(InputStream image, IndexReader reader) throws IOException {

        BufferedImage bufferedImage = ImageIO.read(image);

        return search(bufferedImage, reader);

    }



    public ImageSearchHits relevanceFeedback(ImageSearchHits originalSearch, Set<Document> positives, Set<Document> negatives) {

        throw new UnsupportedOperationException("Not implemented yet for this kind of searcher!");

    }

}


从代码中可以看出AbstractImageSearcher实现了ImageSearcher接口。其中的search(InputStream image, IndexReader reader)方法调用了search(BufferedImage image, IndexReader reader)方法。说白了,就是把2个函数的功能合并为一个函数。

 

ImageSearcherFactory

 

/*

 * This file is part of the LIRe project: http://www.semanticmetadata.net/lire

 * LIRe is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * LIRe 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with LIRe; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 * We kindly ask you to refer the following paper in any publication mentioning Lire:

 *

 * Lux Mathias, Savvas A. Chatzichristofis. Lire: Lucene Image Retrieval 鈥�

 * An Extensible Java CBIR Library. In proceedings of the 16th ACM International

 * Conference on Multimedia, pp. 1085-1088, Vancouver, Canada, 2008

 *

 * http://doi.acm.org/10.1145/1459359.1459577

 *

 * Copyright statement:

 * ~~~~~~~~~~~~~~~~~~~~

 * (c) 2002-2011 by Mathias Lux ([email protected])

 *     http://www.semanticmetadata.net/lire

 */



package net.semanticmetadata.lire;



import net.semanticmetadata.lire.imageanalysis.*;

import net.semanticmetadata.lire.impl.CorrelogramImageSearcher;

import net.semanticmetadata.lire.impl.GenericFastImageSearcher;

import net.semanticmetadata.lire.impl.SimpleImageSearcher;



/**

 * <h2>Searching in an Index</h2>

 * Use the ImageSearcherFactory for creating an ImageSearcher, which will retrieve the images

 * for you from the index.

 * <p/>

 * <pre>

 * IndexReader reader = IndexReader.open(indexPath);

 * ImageSearcher searcher = ImageSearcherFactory.createDefaultSearcher();

 * FileInputStream imageStream = new FileInputStream("image.jpg");

 * BufferedImage bimg = ImageIO.read(imageStream);

 * // searching for an image:

 * ImageSearchHits hits = null;

 * hits = searcher.search(bimg, reader);

 * for (int i = 0; i < 5; i++) {

 * System.out.println(hits.score(i) + ": " + hits.doc(i).getField(DocumentBuilder.FIELD_NAME_IDENTIFIER).stringValue());

 * }

 *

 * // searching for a document:

 * Document document = hits.doc(0);

 * hits = searcher.search(document, reader);

 * for (int i = 0; i < 5; i++) {

 * System.out.println(hits.score(i) + ": " + hits.doc(i).getField(DocumentBuilder.FIELD_NAME_IDENTIFIER).stringValue());

 * }

 * </pre>

 * <p/>

 * This file is part of the Caliph and Emir project: http://www.SemanticMetadata.net

 * <br>Date: 03.02.2006

 * <br>Time: 00:30:07

 *

 * @author Mathias Lux, [email protected]

 */

public class ImageSearcherFactory {

    /**

     * Default number of maximum hits.

     */

    public static int NUM_MAX_HITS = 100;



    /**

     * Creates a new simple image searcher with the desired number of maximum hits.

     *

     * @param maximumHits

     * @return the searcher instance

     * @deprecated Use ColorLayout, EdgeHistogram and ScalableColor features instead.

     */

    public static ImageSearcher createSimpleSearcher(int maximumHits) {

        return ImageSearcherFactory.createColorLayoutImageSearcher(maximumHits);

    }



    /**

     * Returns a new default ImageSearcher with a predefined number of maximum

     * hits defined in the {@link ImageSearcherFactory#NUM_MAX_HITS} based on the {@link net.semanticmetadata.lire.imageanalysis.CEDD} feature

     *

     * @return the searcher instance

     */

    public static ImageSearcher createDefaultSearcher() {

        return new GenericFastImageSearcher(NUM_MAX_HITS, CEDD.class, DocumentBuilder.FIELD_NAME_CEDD);

    }



    /**

     * Returns a new ImageSearcher with the given number of maximum hits

     * which only takes the overall color into account. texture and color

     * distribution are ignored.

     *

     * @param maximumHits defining how many hits are returned in max (e.g. 100 would be ok)

     * @return the ImageSearcher

     * @see ImageSearcher

     * @deprecated Use ColorHistogram or ScalableColor instead

     */

    public static ImageSearcher createColorOnlySearcher(int maximumHits) {

        return ImageSearcherFactory.createScalableColorImageSearcher(maximumHits);

    }



    /**

     * Returns a new ImageSearcher with the given number of maximum hits and

     * the specified weights on the different matching aspects. All weights

     * should be in [0,1] whereas a weight of 0 implies that the feature is

     * not taken into account for searching. Note that the effect is relative and

     * can only be fully applied if the {@link DocumentBuilderFactory#getExtensiveDocumentBuilder() extensive DocumentBuilder}

     * is used.

     *

     * @param maximumHits             defining how many hits are returned in max

     * @param colorHistogramWeight    a weight in [0,1] defining the importance of overall color in the images

     * @param colorDistributionWeight a weight in [0,1] defining the importance of color distribution (which color where) in the images

     * @param textureWeight           defining the importance of texture (which edges where) in the images

     * @return the searcher instance or NULL if the weights are not appropriate, eg. all 0 or not in [0,1]

     * @see DocumentBuilderFactory

     * @deprecated Use ColorLayout, EdgeHistogram and ScalableColor features instead.

     */

    public static ImageSearcher createWeightedSearcher(int maximumHits,

                                                       float colorHistogramWeight,

                                                       float colorDistributionWeight,

                                                       float textureWeight) {

        if (isAppropriateWeight(colorHistogramWeight)

                && isAppropriateWeight(colorDistributionWeight)

                && isAppropriateWeight(textureWeight)

                && (colorHistogramWeight + colorDistributionWeight + textureWeight > 0f))

            return new SimpleImageSearcher(maximumHits, colorHistogramWeight, colorDistributionWeight, textureWeight);

        else

            return null;

    }



    /**

     * Create and return an ImageSearcher for the {@link net.semanticmetadata.lire.imageanalysis.AutoColorCorrelogram}

     * image feature. Be sure to use the same options for the ImageSearcher as you used for the DocumentBuilder.

     *

     * @param maximumHits number of hits returned.

     * @return

     */

    public static ImageSearcher createAutoColorCorrelogramImageSearcher(int maximumHits) {

        return new GenericFastImageSearcher(maximumHits, AutoColorCorrelogram.class, DocumentBuilder.FIELD_NAME_AUTOCOLORCORRELOGRAM);

//        return new CorrelogramImageSearcher(maximumHits, AutoColorCorrelogram.Mode.SuperFast);

    }



    /**

     * Create and return an ImageSearcher for the {@link net.semanticmetadata.lire.imageanalysis.AutoColorCorrelogram}

     * image feature. Be sure to use the same options for the ImageSearcher as you used for the DocumentBuilder.

     *

     * @param maximumHits number of hits returned.

     * @return

     * @deprecated Use #createAutoColorCorrelogramImageSearcher instead

     */

    public static ImageSearcher createFastCorrelogramImageSearcher(int maximumHits) {

        return new CorrelogramImageSearcher(maximumHits, AutoColorCorrelogram.Mode.SuperFast);

    }



    /**

     * Create and return an ImageSearcher for the {@link net.semanticmetadata.lire.imageanalysis.CEDD}

     * image feature. Be sure to use the same options for the ImageSearcher as you used for the DocumentBuilder.

     *

     * @param maximumHits

     * @return

     */

    public static ImageSearcher createCEDDImageSearcher(int maximumHits) {

//        return new CEDDImageSearcher(maximumHits);

        return new GenericFastImageSearcher(maximumHits, CEDD.class, DocumentBuilder.FIELD_NAME_CEDD);

    }





    /**

     * Create and return an ImageSearcher for the {@link net.semanticmetadata.lire.imageanalysis.FCTH}

     * image feature. Be sure to use the same options for the ImageSearcher as you used for the DocumentBuilder.

     *

     * @param maximumHits

     * @return

     */

    public static ImageSearcher createFCTHImageSearcher(int maximumHits) {

//        return new GenericImageSearcher(maximumHits, FCTH.class, DocumentBuilder.FIELD_NAME_FCTH);

        return new GenericFastImageSearcher(maximumHits, FCTH.class, DocumentBuilder.FIELD_NAME_FCTH);

    }





    /**

     * Create and return an ImageSearcher for the {@link net.semanticmetadata.lire.imageanalysis.JCD}

     * image feature. Be sure to use the same options for the ImageSearcher as you used for the DocumentBuilder.

     *

     * @param maximumHits

     * @return

     */

    public static ImageSearcher createJCDImageSearcher(int maximumHits) {

        return new GenericFastImageSearcher(maximumHits, JCD.class, DocumentBuilder.FIELD_NAME_JCD);

    }





    /**

     * Create and return an ImageSearcher for the {@link net.semanticmetadata.lire.imageanalysis.JpegCoefficientHistogram}

     * image feature. Be sure to use the same options for the ImageSearcher as you used for the DocumentBuilder.

     *

     * @param maximumHits

     * @return

     */

    public static ImageSearcher createJpegCoefficientHistogramImageSearcher(int maximumHits) {

        return new GenericFastImageSearcher(maximumHits, JpegCoefficientHistogram.class, DocumentBuilder.FIELD_NAME_JPEGCOEFFS);

    }





    /**

     * Create and return an ImageSearcher for the {@link net.semanticmetadata.lire.imageanalysis.SimpleColorHistogram}

     * image feature. Be sure to use the same options for the ImageSearcher as you used for the DocumentBuilder.

     *

     * @param maximumHits

     * @return

     */

    public static ImageSearcher createColorHistogramImageSearcher(int maximumHits) {

//        return new GenericImageSearcher(maximumHits, SimpleColorHistogram.class, DocumentBuilder.FIELD_NAME_COLORHISTOGRAM);

        return new GenericFastImageSearcher(maximumHits, SimpleColorHistogram.class, DocumentBuilder.FIELD_NAME_COLORHISTOGRAM);

    }



    /**

     * Create and return an ImageSearcher for the {@link net.semanticmetadata.lire.imageanalysis.Tamura}

     * image feature. Be sure to use the same options for the ImageSearcher as you used for the DocumentBuilder.

     *

     * @param maximumHits

     * @return

     */

    public static ImageSearcher createTamuraImageSearcher(int maximumHits) {

        return new GenericFastImageSearcher(maximumHits, Tamura.class, DocumentBuilder.FIELD_NAME_TAMURA);

    }



    /**

     * Create and return an ImageSearcher for the {@link net.semanticmetadata.lire.imageanalysis.Gabor}

     * image feature. Be sure to use the same options for the ImageSearcher as you used for the DocumentBuilder.

     *

     * @param maximumHits

     * @return

     */

    public static ImageSearcher createGaborImageSearcher(int maximumHits) {

        return new GenericFastImageSearcher(maximumHits, Gabor.class, DocumentBuilder.FIELD_NAME_GABOR);

    }



    /**

     * Create and return an ImageSearcher for the {@link net.semanticmetadata.lire.imageanalysis.ColorLayout}

     * image feature using the byte[] serialization. Be sure to use the same options for the ImageSearcher as

     * you used for the DocumentBuilder.

     *

     * @param maximumHits

     * @return

     */

    public static ImageSearcher createColorLayoutImageSearcher(int maximumHits) {

        return new GenericFastImageSearcher(maximumHits, ColorLayout.class, DocumentBuilder.FIELD_NAME_COLORLAYOUT);

    }



    /**

     * Create and return an ImageSearcher for the {@link net.semanticmetadata.lire.imageanalysis.ScalableColor}

     * image feature using the byte[] serialization. Be sure to use the same options for the ImageSearcher as

     * you used for the DocumentBuilder.

     *

     * @param maximumHits

     * @return

     */

    public static ImageSearcher createScalableColorImageSearcher(int maximumHits) {

        return new GenericFastImageSearcher(maximumHits, ScalableColor.class, DocumentBuilder.FIELD_NAME_SCALABLECOLOR);

    }



    /**

     * Create and return an ImageSearcher for the {@link net.semanticmetadata.lire.imageanalysis.EdgeHistogram}

     * image feature using the byte[] serialization. Be sure to use the same options for the ImageSearcher as

     * you used for the DocumentBuilder.

     *

     * @param maximumHits

     * @return

     */

    public static ImageSearcher createEdgeHistogramImageSearcher(int maximumHits) {

        return new GenericFastImageSearcher(maximumHits, EdgeHistogram.class, DocumentBuilder.FIELD_NAME_EDGEHISTOGRAM);

    }





    /**

     * Checks if the weight is in [0,1]

     *

     * @param f the weight to check

     * @return true if the weight is in [0,1], false otherwise

     */

    private static boolean isAppropriateWeight(float f) {

        boolean result = false;

        if (f <= 1f && f >= 0) result = true;

        return result;



    }

}


ImageSearcherFactory是用于创建ImageSearcher的。里面有各种create****ImageSearcher()。每个函数的作用在注释中都有详细的说明。


ImageSearchHits

 

/*

 * This file is part of the LIRe project: http://www.semanticmetadata.net/lire

 * LIRe is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * LIRe 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with LIRe; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 * We kindly ask you to refer the following paper in any publication mentioning Lire:

 *

 * Lux Mathias, Savvas A. Chatzichristofis. Lire: Lucene Image Retrieval 鈥�

 * An Extensible Java CBIR Library. In proceedings of the 16th ACM International

 * Conference on Multimedia, pp. 1085-1088, Vancouver, Canada, 2008

 *

 * http://doi.acm.org/10.1145/1459359.1459577

 *

 * Copyright statement:

 * --------------------

 * (c) 2002-2011 by Mathias Lux ([email protected])

 *     http://www.semanticmetadata.net/lire

 */



package net.semanticmetadata.lire;



import org.apache.lucene.document.Document;



/**

 * This class simulates the original Lucene Hits object.

 * Please note the only a certain number of results are returned.<br>

 * <p/>

 * This file is part of the Caliph and Emir project: http://www.SemanticMetadata.net

 * <br>Date: 02.02.2006

 * <br>Time: 23:45:20

 *

 * @author Mathias Lux, [email protected]

 */

public interface ImageSearchHits {

    /**

     * Returns the size of the result list.

     *

     * @return the size of the result list.

     */

    public int length();



    /**

     * Returns the score of the document at given position.

     * Please note that the score in this case is a distance,

     * which means a score of 0 denotes the best possible hit.

     * The result list starts with position 0 as everything

     * in computer science does.

     *

     * @param position defines the position

     * @return the score of the document at given position. The lower the better (its a distance measure).

     */

    public float score(int position);



    /**

     * Returns the document at given position

     *

     * @param position defines the position.

     * @return the document at given position.

     */

    public Document doc(int position);

}


该类主要用于存储ImageSearcher类中search()方法返回的结果。

 


SimpleImageSearchHits是ImageSearcher的实现。该类的源代码如下所示:

 

/*

 * This file is part of the LIRe project: http://www.semanticmetadata.net/lire

 * LIRe is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * LIRe 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with LIRe; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 * We kindly ask you to refer the following paper in any publication mentioning Lire:

 *

 * Lux Mathias, Savvas A. Chatzichristofis. Lire: Lucene Image Retrieval 鈥�

 * An Extensible Java CBIR Library. In proceedings of the 16th ACM International

 * Conference on Multimedia, pp. 1085-1088, Vancouver, Canada, 2008

 *

 * http://doi.acm.org/10.1145/1459359.1459577

 *

 * Copyright statement:

 * --------------------

 * (c) 2002-2011 by Mathias Lux ([email protected])

 *     http://www.semanticmetadata.net/lire

 */



package net.semanticmetadata.lire.impl;



import net.semanticmetadata.lire.ImageSearchHits;

import org.apache.lucene.document.Document;



import java.util.ArrayList;

import java.util.Collection;

import java.util.Iterator;



/**

 * This file is part of the Caliph and Emir project: http://www.SemanticMetadata.net

 * <br>Date: 02.02.2006

 * <br>Time: 23:56:15

 *

 * @author Mathias Lux, [email protected]

 */

public class SimpleImageSearchHits implements ImageSearchHits {

    ArrayList<SimpleResult> results;



    public SimpleImageSearchHits(Collection<SimpleResult> results, float maxDistance) {

        this.results = new ArrayList<SimpleResult>(results.size());

        this.results.addAll(results);

        // this step normalizes and inverts the distance ...

        // although its now a score or similarity like measure its further called distance

        for (Iterator<SimpleResult> iterator = this.results.iterator(); iterator.hasNext(); ) {

            SimpleResult result = iterator.next();

            result.setDistance(1f - result.getDistance() / maxDistance);

        }

    }



    /**

     * Returns the size of the result list.

     *

     * @return the size of the result list.

     */

    public int length() {

        return results.size();

    }



    /**

     * Returns the score of the document at given position.

     * Please note that the score in this case is a distance,

     * which means a score of 0 denotes the best possible hit.

     * The result list starts with position 0 as everything

     * in computer science does.

     *

     * @param position defines the position

     * @return the score of the document at given position. The lower the better (its a distance measure).

     */

    public float score(int position) {

        return results.get(position).getDistance();

    }



    /**

     * Returns the document at given position

     *

     * @param position defines the position.

     * @return the document at given position.

     */

    public Document doc(int position) {

        return results.get(position).getDocument();

    }



    private float sigmoid(float f) {

        double result = 0f;

        result = -1d + 2d / (1d + Math.exp(-2d * f / 0.6));

        return (float) (1d - result);

    }

}


可以看出检索的结果是存在名为results的ArrayList<SimpleResult> 类型的变量中的。

 








 

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