Easy Speech Recognition in Python with PyAudio and Pocketsphinx

If you remember, I was getting started with Audio Processing in Python (thinking of implementing an audio classification system) a couple of weeks back (see my earlier post). I got the PyAudio package setup and was having some success with it. As you know, one of the more interesting areas in audio processing in machine learning is Speech Recognition. So, although it wasn't my original intention of the project, I thought of trying out some speech recognition code as well.

I searched around to see what Python packages are available for the task and found the SpeechRecognition package.

Python Speech Recognition running with Sphinx

SpeechRecognition is a library for Speech Recognition (as the name suggests), which can work with many Speech Engines and APIs. The current version supports the following engines and APIs,

• CMU Sphinx
• Google Speech Recognition
• Google Cloud Speech API
• Wit.ai
• Microsoft Bing Voice Recognition
• Houndify API
• IBM Speech to Text

I decided to start with the Sphinx engine since it was the only one that worked offline. But keep in mind that Sphinx is not as accurate as something like Google Speech Recognition.

First, let's set up the SpeechRecognition package.

Setting up TensorFlow with CUDA on Windows

I did the post about How to setup TensorFlow on Windows about a month back. I only covered setting up the CPU version of TensorFlow there, and promised that I'll do the guide for the GPU version soon. But I haven't had the change to come round to write the guide until now.

I guess better late than never. So, here's how to setup the GPU version of TensorFlow on Windows.

So, what do you need to get TensorFlow working on GPU?
You need to setup the following prerequisites, in that order.

1. Microsoft Visual Studio 2015 (The free community edition of VS 2015 will work)
2. CUDA 8.0
3. cuDNN 5.1 for CUDA 8.0

Start by installing Visual Studio 2015. You can get the free community edition from here. When you install, make sure to select ‘Custom Installation’, and select ‘Visual C++’ in the programming language selection (by default, C++ is not selected). Once installed, check whether you have C++ capability by checking the ‘New Project’ options.

Visual Studio 2015 installed with C++

How to Graph Model Training History in Keras

When we are training a machine learning model in Keras, we usually keep track of how well the training is going (the accuracy and the loss of the model) using the values printed out in the console. Wouldn't it be great if we can visualize the training progress? Not only would it be easier to see how well the model trained, but it would also allow us to compare models.

Something like this?

Training accuracy and loss for 100 epochs

Well, you can actually do it quite easily, by using the History objects of Keras along with Matplotlib.