/** Convert word graph to phoneme graph */
private Graph buildPhonemeGraph(Graph wordGraph) {
Graph phonemeGraph = new Graph();
phonemeGraph.copyGraph(wordGraph);
for (Node node : phonemeGraph.nodeToArray()) {
if (node.getType().equals(NodeType.WORD)) {
String word = node.getID();
// "false" means graph won't have additional dummy
// nodes surrounding the word
Graph pronunciationGraph = dictionary.getWordGraph(word, false);
phonemeGraph.insertGraph(pronunciationGraph, node);
}
}
return phonemeGraph;
}
/**
* Convert the phoneme graph to an HMM.
*
* @param cdGraph a context dependent phoneme graph
* @return an HMM graph for a context dependent phoneme graph
*/
public Graph buildHMMGraph(Graph cdGraph) {
Graph hmmGraph = new Graph();
hmmGraph.copyGraph(cdGraph);
for (Node node : hmmGraph.nodeToArray()) {
Unit unit = null;
if (node.getType().equals(NodeType.PHONE)) {
unit = unitManager.getUnit(node.getID());
} else if (node.getType().equals(NodeType.SILENCE_WITH_LOOPBACK)) {
unit = unitManager.getUnit("SIL");
} else {
// if it's not a phone, and it's not silence, it's a
// dummy node, and we don't care.
continue;
}
HMM hmm = acousticModel.lookupNearestHMM(unit, HMMPosition.UNDEFINED, false);
Graph modelGraph = buildModelGraph((SenoneHMM) hmm);
modelGraph.validate();
hmmGraph.insertGraph(modelGraph, node);
}
return hmmGraph;
}
/**
* Convert phoneme graph to a context sensitive phoneme graph. This graph expands paths out to
* have separate phoneme nodes for phonemes in different contexts.
*
* @param phonemeGraph the phoneme graph
* @return a context dependendent phoneme graph
*/
public Graph buildContextDependentPhonemeGraph(Graph phonemeGraph) {
// TODO: Dummy stub for now - return a copy of the original graph
Graph cdGraph = new Graph();
cdGraph.copyGraph(phonemeGraph);
return cdGraph;
}
