content: /*  ContourCenterOfGravityFeatureExtractor.java
  
      Copyright (c) 2009-2014 Andrew Rosenberg
  
    This file is part of the AuToBI prosodic analysis package.
  
    AuToBI is free software: you can redistribute it and/or modify
    it under the terms of the Apache License (see boilerplate below)
  
   ***********************************************************************************************************************
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
   * the License. You should have received a copy of the Apache 2.0 License along with AuToBI.
   * 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 edu.cuny.qc.speech.AuToBI.featureextractor;
  
  import edu.cuny.qc.speech.AuToBI.core.*;
  import edu.cuny.qc.speech.AuToBI.util.ContourUtils;
  
  import java.util.List;
  
  /**
   * ContourCenterOfGravityFeatureExtractor identifies the "Center of Gravity" in time of a contour.
   * <p/>
   * This has typically been used on f0 contours and called "Tonal Center of Gravity" or ToCG.
   * <p/>
   * Here we allow any contour -- intensity, spectral tilt, etc -- to be processed using the same notion.
   */
  @SuppressWarnings("unchecked")
  public class ContourCenterOfGravityFeatureExtractor extends FeatureExtractor {
    public static final String moniker = "cog";
    private String attribute_name;       // the contour attribute name
  
    public ContourCenterOfGravityFeatureExtractor(String attribute_name) {
      this.attribute_name = attribute_name;
      extracted_features.add("cog[" + attribute_name + "]");
      required_features.add(attribute_name);
    }
  
    /**
     * Extracts center of gravity features for each region from the contour.
     *
     * @param regions The regions to extract features from.
     * @throws FeatureExtractorException if something goes wrong
     */
    public void extractFeatures(List regions) throws FeatureExtractorException {
      for (Region r : (List<Region>) regions) {
        if (r.hasAttribute(attribute_name)) {
          Contour super_c = (Contour) r.getAttribute(attribute_name);
          Contour c;
          try {
            c = ContourUtils.getSubContour(super_c, r.getStart(), r.getEnd());
          } catch (AuToBIException e) {
            throw new FeatureExtractorException(e.getMessage());
          }
          double num = 0.0;
          double denom = 0.0;
          for (Pair<Double, Double> tvp : c) {
            num += tvp.first * tvp.second;
            denom += tvp.second;
          }
          if (denom != 0.0) {
            r.setAttribute("cog[" + attribute_name + "]", ((num / denom) - r.getStart()) / r.getDuration());
          }
        }
      }
    }
  }
  