ImageCompareEvaluator.java

/*******************************************************************************
 * Copyright 2006 - 2012 Vienna University of Technology,
 * Department of Software Technology and Interactive Systems, IFS
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/
package at.tuwien.minimee.migration.evaluators;

import java.io.File;
import java.util.ArrayList;
import java.util.List;

import at.tuwien.minimee.util.CommandExecutor;
import at.tuwien.minimee.util.OS;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import eu.scape_project.planning.model.measurement.Measurement;
import eu.scape_project.planning.model.scales.Scale;

/**
 * This evaluator uses the ImageMagick COMPARE script to measure the difference
 * of two images. For this, ImageMagick must be defined properly! That means,
 * you need to set the IMAGEMAGICK_HOME environment variable to point to your
 * installation directory.
 * 
 * @author cb
 * 
 */
public class ImageCompareEvaluator implements IMinimeeEvaluator {
    private String name;
    private Logger log = LoggerFactory.getLogger(this.getClass());
    private String compareCommand = "%IMAGEMAGICK_HOME%/compare %FILE1% %FILE2% -metric %METRIC% tempimagefile";

    private String IMAGEMAGICK_HOME;

    /**
     * @throws IllegalStateException
     *             if IMAGEMAGICK_HOME is not set
     */
    public ImageCompareEvaluator() {
        IMAGEMAGICK_HOME = System.getenv("IMAGEMAGICK_HOME");

        //
        // IMAGEMAGICK_HOME is set and the directory exists
        if (IMAGEMAGICK_HOME != null && new File(IMAGEMAGICK_HOME).exists()) {
            compareCommand = compareCommand.replace("%IMAGEMAGICK_HOME%", new File(IMAGEMAGICK_HOME).getAbsolutePath());

            return;
            //
            // IMAGEMAGICK_HOME is not set, but the operating system is Linux
            // and the ImageMagick is installed
        } else if (IMAGEMAGICK_HOME == null && ("Linux".compareTo(System.getProperty("os.name")) == 0)
            && new File("/usr/bin/compare").exists()) {
            compareCommand = compareCommand.replace("%IMAGEMAGICK_HOME%", "/usr/bin");

            return;
        }

        //
        // in all other cases, where IMAGEMAGICK_HOME is not set, we throw an
        // exception.
        if (IMAGEMAGICK_HOME == null) {
            throw new IllegalStateException(
                "ImageMagick is not propertly configured - IMAGEMAGICK_HOME is not defined.");
        }
    }

    public List<Measurement> evaluate(String tempDir, String file1, String file2) {
        List<Measurement> list = new ArrayList<Measurement>();
        String[] metrics = new String[] { // see
                                          // http://www.imagemagick.org/Usage/compare/#statistics
        "AE", // Absolute Error count of the number of different pixels
              // (0=equal)
            "PAE", // Peak Absolute Error
            "PSNR", // Peak Signal to noise ratio
            "MAE", // Mean absolute error (average channel error distance)
            "MSE", // Mean squared error (averaged squared error distance)
            "RMSE", // (sq)root mean squared error -- IE: sqrt(MSE)
            "MEPP" // Normalized Mean Error AND Normalized Maximum Error
        };

        for (String metric : metrics) {
            Double value = evaluate(tempDir, file1, file2, metric);
            list.add(new Measurement("imagequality:" + metric, value));
        }
        return list;
    }

    public Double evaluate(String tempDir, String file1, String file2, String metric) {
        String commandTemplate = compareCommand.replace("%FILE1%", file1).replace("%FILE2%", file2);

        CommandExecutor cmdEx = new CommandExecutor();
        cmdEx.setWorkingDirectory(OS.getTmpPath());
        String command = commandTemplate.replace("%METRIC%", metric);
        try {
            cmdEx.runCommand(command);
            String out = cmdEx.getCommandError();
            log.debug(command + " == " + out);
            Double value = Scale.MAX_VALUE;

            try {
                if (out.contains(" ")) {
                    out = out.substring(0, out.indexOf(" "));
                }
                value = Double.valueOf(out.trim());
            } catch (NumberFormatException e) {
                log.error("unknown numberformat: " + out + " " + e.getMessage());
            }
            return value;
        } catch (Exception e) {
            log.error("error during image comparison " + command + " : " + cmdEx.getCommandError(), e);
            return null;
        }
    }

    /**
     * unused
     */
    public String getConfigParam() {
        return null;
    }

    /**
     * unused
     */
    public void setConfigParam(String configParam) {
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}