Adds FeatureExtractor and corresponding test class;

sphinx4-core/src/main/java/edu/cmu/sphinx/api/FeatureExtractor.java

@@ -0,0 +1,146 @@
+package edu.cmu.sphinx.api;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.logging.Logger;
+
+import edu.cmu.sphinx.frontend.Data;
+import edu.cmu.sphinx.frontend.DataEndSignal;
+import edu.cmu.sphinx.frontend.DataProcessingException;
+import edu.cmu.sphinx.frontend.DoubleData;
+import edu.cmu.sphinx.frontend.FloatData;
+import edu.cmu.sphinx.frontend.FrontEnd;
+import edu.cmu.sphinx.frontend.util.StreamDataSource;
+import edu.cmu.sphinx.util.props.ConfigurationManager;
+
+/**
+ * Extracts features from input stream
+ * 
+ * @author Vladisav Jelisavcic
+ * 
+ */
+class FeatureExtractor {
+    private FrontEnd frontEnd;
+    private StreamDataSource audioSource;
+    private int featureLength = -1;
+
+    /** The logger for this class */
+    private static final Logger logger = Logger
+            .getLogger("edu.cmu.sphinx.api.FeatureExtractor");
+
+    /**
+     * Constructs a FeatureExtractor. 
+     * 
+     * @param cm
+     *            the configuration manager
+     * @param frontEndName
+     *            the name for the frontEnd to be used
+     * @param inputStream
+     * 			  data stream 
+     *            
+     * @throws IOException if error occurred
+     */
+    public FeatureExtractor(ConfigurationManager cm, String frontEndName, InputStream inputStream)
+            throws IOException {
+
+        if(cm.lookup(frontEndName) == null) {
+        	throw new RuntimeException("No such frontend: " + frontEndName);
+        }
+
+        frontEnd = (FrontEnd) cm.lookup(frontEndName);
+        audioSource = (StreamDataSource) cm.lookup("streamDataSource");
+        audioSource.setInputStream(inputStream);
+    }
+
+    /**
+     * Extracts all features from the supplied InputStream. 
+     * 
+     * @return float[][] when called first time, null otherwise 
+     * 
+     * @throws DataProcessinException if error occurred
+     */
+	public float[][] getAllFeatures() throws DataProcessingException {
+		List<float[]> featureList = new ArrayList<float[]>();
+
+	    Data feature = frontEnd.getData();
+	    if(feature == null)
+	    	return null;
+
+        while (!(feature instanceof DataEndSignal)) {
+            if (feature instanceof DoubleData) {
+                double[] featureData = ((DoubleData) feature).getValues();
+                if (featureLength < 0) {
+                    featureLength = featureData.length;
+                    logger.info("Feature length: " + featureLength);
+                }
+                float[] convertedData = new float[featureData.length];
+                for (int i = 0; i < featureData.length; i++) {
+                    convertedData[i] = (float) featureData[i];
+                }
+                featureList.add(convertedData);
+            } else if (feature instanceof FloatData) {
+                float[] featureData = ((FloatData) feature).getValues();
+                if (featureLength < 0) {
+                    featureLength = featureData.length;
+                    logger.info("Feature length: " + featureLength);
+                }
+                featureList.add(featureData);
+            }
+            feature = frontEnd.getData();
+        }
+
+	     float[][] allFeatures = new float[featureList.size()][];
+	     for(int i=0;i<featureList.size();i++){
+	    	 allFeatures[i] = featureList.get(i);
+	     }
+	     return allFeatures;
+
+	} 
+
+
+    /**
+     * Extracts a single feature frame from the supplied InputStream. 
+     * 
+     * @return float[] or null if end of stream reached
+     * 
+     * @throws DataProcessinException if error occurred
+     */
+	public float[] getNextFeatureFrame() throws DataProcessingException{
+	    Data feature = frontEnd.getData();
+	    if(feature == null)
+	    	return null;
+
+        while (!(feature instanceof DoubleData || feature instanceof FloatData)) {
+        	feature = frontEnd.getData();
+        	if(feature == null)
+        		return null;
+        }
+
+
+        if (feature instanceof DoubleData) {
+            double[] featureData = ((DoubleData) feature).getValues();
+            if (featureLength < 0) {
+                featureLength = featureData.length;
+                logger.info("Feature length: " + featureLength);
+            }
+            float[] convertedData = new float[featureData.length];
+            for (int i = 0; i < featureData.length; i++) {
+                convertedData[i] = (float) featureData[i];
+            }
+            return convertedData;
+        } else if (feature instanceof FloatData) {
+            float[] featureData = ((FloatData) feature).getValues();
+            if (featureLength < 0) {
+                featureLength = featureData.length;
+                logger.info("Feature length: " + featureLength);
+            }
+            return featureData;
+        }
+        return null;
+
+	} 
+
+
+}

sphinx4-core/src/test/java/edu/cmu/sphinx/api/FeatureExtractorTest.java

@@ -0,0 +1,109 @@
+/**
+ * 
+ */
+package edu.cmu.sphinx.api;
+
+import static org.testng.AssertJUnit.assertEquals;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.util.Scanner;
+
+import org.testng.annotations.AfterTest;
+import org.testng.annotations.BeforeTest;
+import org.testng.annotations.Test;
+
+import edu.cmu.sphinx.util.props.ConfigurationManager;
+
+
+/**
+ * @author Vladisav Jelisavcic
+ *
+ */
+public class FeatureExtractorTest {
+
+	static final String FRONTEND_NAME = "cepstraFrontEnd"; 
+	private float[] features;
+
+	@BeforeTest
+	public void setUp(){
+		InputStream asciiStream = FeatureExtractorTest.class
+                .getResourceAsStream("/edu/cmu/sphinx/api/10001-90210-01803.features");
+		Scanner sc = new Scanner(asciiStream);
+		int numDataPoints = sc.nextInt();
+		System.out.println(numDataPoints);
+
+		features = new float[numDataPoints];
+		int i = 0;
+		while(sc.hasNextFloat()){
+			features[i++] = sc.nextFloat();
+		}
+		sc.close();
+
+	}
+
+	@AfterTest
+	public void tearDown(){
+
+	}
+
+	/**
+	 * Test method for {@link edu.cmu.sphinx.api.FeatureExtractor#getAllFeatures()}.
+	 * @throws IOException 
+	 */
+	@Test
+	public void testGetAllFeatures() throws IOException {	
+		URL url = FeatureExtractorTest.class
+				.getResource("/edu/cmu/sphinx/tools/feature/frontend.config.xml");
+
+		ConfigurationManager cm = new ConfigurationManager(url);
+
+		InputStream audioStream = FeatureExtractorTest.class
+                .getResourceAsStream("/edu/cmu/sphinx/tools/bandwidth/10001-90210-01803.wav");
+
+		FeatureExtractor fe = new FeatureExtractor(cm,FRONTEND_NAME,audioStream);
+		float[][] data = fe.getAllFeatures();
+
+		int numSamples = data.length;
+		int numFeatures = data[0].length;
+
+		int numDataPoints = numSamples * numFeatures;
+
+		assertEquals(features.length,numDataPoints); // check if all data points are loaded
+		for(int i=0;i<numSamples;i++){
+			for(int j=0;j<numFeatures;j++){
+				assertEquals(features[i*numFeatures+j],data[i][j]); 
+			}
+		}
+	}
+
+	/**
+	 * Test method for {@link edu.cmu.sphinx.api.FeatureExtractor#getNextFeatureFrame()}.
+	 * @throws IOException 
+	 */
+	@Test
+	public void testGetNextFeatureFrame() throws IOException {
+		URL url = FeatureExtractorTest.class
+				.getResource("/edu/cmu/sphinx/tools/feature/frontend.config.xml");
+
+		ConfigurationManager cm = new ConfigurationManager(url);
+
+		InputStream audioStream = FeatureExtractorTest.class
+                .getResourceAsStream("/edu/cmu/sphinx/tools/bandwidth/10001-90210-01803.wav");
+
+		FeatureExtractor fe = new FeatureExtractor(cm,FRONTEND_NAME,audioStream);
+
+		int numDataPoints = 0;
+		float[] data;
+		while((data = fe.getNextFeatureFrame()) != null){
+			for(int i=0;i<data.length;i++){
+				assertEquals(features[i+numDataPoints],data[i]); 
+			}
+			numDataPoints += data.length;
+		}
+
+		assertEquals(features.length,numDataPoints); // check if all data points are loaded
+	}
+
+}