Linguist Module in Sphinx-4 By Sonthi Dusitpirom

Objective  How to change dictionary in Sphinx-4

Sphinx-4  Sphinx-4 is an open source framework for speech recognition, written in the Java programming to help in the research of speech recognition system. In Sphinx-4 it has 3 main components  The FrontEnd  The Decoder  The Linguist

Sphinx-4

 In this project we focus on the Linguist component that has 3 subcomponents  The Acoustic Model Acoustic model is pronounced of individual characters, known as phonemes.  The Dictionary Dictionary is the pronunciation of all the words that the system can recognize.  The Language Model Language model describes how the grammar looks like.

Acoustic Model  The acoustic model in Sphinx-4 consists of a set of left-to-right Hidden Markov Models for basic sound units. The units represent phones in a triphone context.  The acoustic model in Sphinx-4 is packed in JAR file. The advantage of packing it in a JAR file is that the file can be included in the classpath and referenced in the configuration file for it to be used in a Sphinx-4 application.

Acoustic Model  In sphix-4 we have two important models that are for difference purpose  TIDIGITS_8gau_13dCep_16k_40mel_130Hz_6800.jar is designed and created for number. If you need to recognize number then you should use this model  WSJ_8gau_13dCep_16k_40mel_130Hz_6800.jar is designed and created for text. If you want to recognize text then you should use this model.

Dictionary  Dictionary provides pronunciations for words found in the language model. The pronunciations split words into sequences of phonemes that found in the acoustic model.

Language Model  There are two types of model that describe language  Grammars language model Grammars describe very simple types of languages for command and control, and you are written by hand or generated automatically with plain code.  Statistical language model Statistical language model estimate the probability of the distribution of natural language. The most widely used statistical language model is N-gram

Create a new dictionary  In Sphinx-4 we already have a dictionary. This is the way to change dictionary  Extract WSJ_8gau_13dCep_16k_40mel_130Hz_6800Hz.jar in lib directory.  Go to dict folder and open cmudict.0.6.d file in that folder.  Insert words and phonemes into cmudict.0.6d file and save.  Zip the folder that we extract in zip file.  Remove WSJ_8gau_13dCep_16k_40mel_130Hz_6800Hz.jar from libraries in build path and add zip file into libraries in build path.

XML Configuration File  The configuration of a particular Sphin-4 system is determined by a configuration file. This configuration file defines the following  The names and types of all of the components of the system.  The connectivity of these components – that is, which components talk to each other.  The detailed configuration for each of these elements.

XML configuration File  Determining which components are to be used in the system.  Determining the detailed configuration of each of these components.

Use Model in Sphinx-4  There are three steps to use new model from Sphinx-4  Defining a language model.  Defining a dictionary.  Defining an acoustic model.

Define a Language Model <property name="grammarLocation“ value=" the path to the grammar folder "/> <property name="dictionary" value="dictionary"/> <property name="grammarName" value=“the name of grammar"/> <property name="logMath“ value="logMath"/>

Define a Language Model <property name="unigramWeight“ value="0.7"/> <property name="maxDepth" value="3"/> <property name="logMath" value="logMath"/> <property name="dictionary" value="dictionary"/> <property name="location" value="the name of the language model file "

Define a Dictionary <property name="dictionaryPath" value="the name of the dictionary file" value="the name of the filler file"/> <property name="allowMissingWords" value="false"/> <property name="unitManager" value="unitManager"/>

Define an Acoustic Model <property name="location" value="the path to the model folder"/> <property name="location" value="the path to the model folder"/>

Any Question ?