I’m back with a very big question.
How to improve accuracy ?!?!?
Its been a week, I’m getting 2-3 mails everyday regarding “How to improve accuracy”. So this post is answer to all those and upcoming mails. First of all the problem is really big and complex, And to understand the problem first you need to understand the very basics of Speech Recognition and background process of Speech Recognition.
Basics of Speech Recognition are not Java coding part Or Whats gram file Or Why we use Recognizer and Microphone classes .. NO !
Remember ! Changes in Java Coding will not make any major effect in Accuracy. You need to focus on config.xml file.
To solve this problem, All you need to do is, understand the Automatic Speech Recognition, Search and Language Processing Algo’s. Specifically on Sphinx, you need understanding of Hidden Markov Models ( HMMs ) methods of Speech Recognition, Beam Searching, Language Configs and Modeling. Its highly recommended to read any good book before you continue to work on it.
Before we apply the configs on our application to give more accurate results, We must know to how to track results.
Next part is, Knowing what kind of SR application you are creating. Basically, SR applications are divided into 2 major categories : Dictation and Command
Command Application When words are very few And Dictation Application When you have a large vocabulary.
And for both type of applications we need a language model or grammar file respectively. A language model is a file containing the probabilities of sequences of words. A grammar is a much smaller file containing sets of predefined combination of words.
Now again on the most important part, Accuracy Tracking. Find as many resources, examples, notes you can. Finally collect databases, Few are also available on Sphinx website. Work on it. Recognize it. Try to get your best results.
Expected Results in Silent Environment :
Command : 5% WER
Medium Vocabulary : 15% WER
Large Vocabulary : 30% WER
If environment is noisy, Multiply the results by 2.
If you are not getting the expected results. Keep trying and try to find the bugs in config file and run time reports.
Still if you are not happy with the results And have got extra time. Open the config.xml file and start playing with Configs and keep experimenting. Also, Make sure you make notes on every configs and their outputs.
If you have any better ideas or any suggestions, Please feel free to post comments.
That’s it for now ! Signing off.