Fixing the KeyError: 'acc' and KeyError: 'val_acc' Errors in Keras 2.3.x

Have you been using the 'History' object returned by the fit() functions of Keras to graph or visualize the training history of your models? And have you been getting a 'KeyError' type error such as the following since recent Keras upgrade and wondering why?

Traceback (most recent call last):
  File "lenet_mnist_keras.py", line 163, in <module>
    graph_training_history(history)
  File "lenet_mnist_keras.py", line 87, in graph_training_history
    plt.plot(history.history['acc'])
KeyError: 'acc'

The KeyError: 'acc' when attempting to read the history object

Traceback (most recent call last):
  File "lenet_mnist_keras.py", line 163, in <module>
    graph_training_history(history)
  File "lenet_mnist_keras.py", line 88, in graph_training_history
    plt.plot(history.history['val_acc'])
KeyError: 'val_acc'

The KeyError: 'val_acc' when attempting to read the history object

Well, this is due to a breaking change introduced in Keras release 2.3.0.

Cleaning up your Anaconda installations

If you've been using Anaconda Python for a while, and been creating multiple environments and adding/removing packages, you may have noticed that it's starting to take up a lot of disk space (sometimes tens of GBs).

Anaconda installation can get big

One reason is that anaconda environments are completely isolated workspaces from each other with their own copy of Python. So, the more environments you have, the larger the space needed by anaconda. But the other reason is that anaconda keeps a cache of the package files, tarballs etc. of the packages you've installed. This is great when you need to reinstall the same packages. But, over time, the space can add up.

So, how do we clean up this cache and regain some disk space?

Fixing the Matplotlib PyPlot import errors

About a week back, I was reinstalling Keras, TensorFlow and all the other libraries after a reformat of my PC. When I started verifying the library installations, I came across a strange error. When I tried to run a simple deep learning model, Python runtime crashed. As soon as I execute the script I was getting the "python.exe has stopped working" error message (I'm using Windows 10).

Matplotlib is an important part of my deep learning workflows

A little bit of debugging narrowed down the error to the following line in my script.

import matplotlib.pyplot as plt

(I was using matplotlib to graph the training history of the model. See "How to Graph Model Training History in Keras")

The error did not occur if I simply import matplotlib. It only occurred when specifically importing the pyplot module.

import matplotlib
# no errors

import matplotlib.pyplot as plt
# crash!!!

This is a known issue due to some library conflicts in the installation, which should hopefully be fixed in a future release. Until then, if you're getting this error, you can fix it by following the steps below.

Need More Fonts on OpenCV?

OpenCV has a built-in simple function to add text on your images - the cv2.putText() function. With just one line of code, you can add text anywhere on the image. You just need to specify the position, colour, scale (font size), and which the font to use as the minimum parameters.

 cv2.putText(image,  
           text_to_show,  
           (20, 40),  
           fontFace=cv2.FONT_HERSHEY_SIMPLEX,  
           fontScale=1,  
           color=(255, 255, 255))  

OpenCV also gives you a choice from a handful of fonts - all variants of the "Hershey" font.

But, there may come a point where you want more fonts. Have you wished that you could use a specific True Type or Open Type font on OpenCV?

The good news is, it's possible.

True Type Fonts working on OpenCV

Snapchat like Image Overlays with Dlib, OpenCV, and Python

You're probably familiar with Snapchat, and it's filters feature where you can put some cool and funny image overlays on your face images. As computer vision enthusiasts, we typically look at applications like these, and try to understand how it's done, and whether we can build something similar.

It turns out, we can make our own application with Snapchat like image overlays using Python, OpenCV, and Dlib.

Snapchat like Image Overlays with Dlib, OpenCV, and Python

So, how do we build it?

1. We'll first load the Webcam feed using OpenCV.
2. We'll load an image (in our example, and image for the 'eye') to be used as the overlay.
3. Use Dlib's face detection to localize the faces, and then use facial landmarks to find where the eyes are.
4. Calculate the size and the position of the overlay for each eye.
5. Finally, place the overlay image over each eye, resized to the correct size.

Let's start.

Machine UI : An IDE for Machine Learning, currently in Alpha

Machine UI, or just "Machine" as it's commonly referred, is an IDE for Machine Learning, which is currently in its Alpha stage. It has been designed to work with TensorFlow, and aims at simplifying setting up machine Learning experiments so that you spend more time experimenting, and less time configuring.

The interface of Machine UI (Note: This is a screenshot from their announcement video)

As per their announcement video, the machine learning experiments are set up visually. The input data, convolutions, and the outputs are placed as nodes on a graph. You can think of it as a more interactive version of the Tensor Board which comes with TensorFlow.

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++

Installing OpenCV 3 on Anaconda Python 3.5 on Windows

If you checked my last post, you know that TensorFlow now officially works on Windows. This was really exciting to me, since I was using a Linux machine for my TensorFlow experiments, I had to switch between the Linux and Windows for my other tasks. Now, I should be able to perform some of those experiments on Windows as well. (I would still switch to Linux for more processor intensive deep learning models). So, I decided to set everything up on Windows again.

I've been using OpenCV 3 on Anaconda Python 3.5 on Linux. (Check out my guide on Installing OpenCV from source on Anaconda Python on Ubuntu 16.10 if you are trying to install on Linux). But on Windows, I've previously only tried OpenCV on Python 2.7. Since the OpenCV Downloads page has pre-built binaries for OpenCV 3 (version 3.2 being latest), I thought the installation would be straightforward.

I downloaded and ran the OpenCV 3.2 installer (which just extracts OpenCV to a directory of your choosing), set the OPENCV_DIR environment variable, add the bin dir in OpenCV to the PATH, and finally copy the cv2.pyd file to the site-packages directory in my Anaconda environment. I fired up the Anaconda environment, and tried loading cv2 in Python. But I got the following error,

 (tensorflow) C:\>python  
 Python 3.5.2 |Continuum Analytics, Inc.| (default, Jul 5 2016, 11:41:13) [MSC v  
 .1900 64 bit (AMD64)] on win32  
 Type "help", "copyright", "credits" or "license" for more information.  
 >>> import cv2  
 Traceback (most recent call last):  
  File "<stdin>", line 1, in <module>  
 ImportError: DLL load failed: The specified module could not be found.  

Stepping into audio classification - Getting started with PyAudio

I've had an idea to attempt to train a deep learning model that can classify different audio noises. Having a system that can accurately identify different sounds would have implications in many fields, from medical diagnostics to echo locations systems, among others. I wouldn't expect building such a system would be an easy task. But, let's give it a try.

I first had the idea about 8 years back. But back then, libraries that enable audio processing were scarce, and what was available required a massive effort to get installed. Now it seems that things have improved a lot. I myself was searching online for audio processing libraries for Python, and I came across this excellent post - Realtime Audio Visualization in Python - by Scott Harden of University of Florida.

Realtime Audio Visualization with PyAudio

The tutorial uses the PyAudio Python package (PyAudio homepage), which is the Python bindings for PortAudio (PortAudio homepage) - a cross-platform audio I/O library - allowing PyAudio to give a consistent interface to process audio across platforms. So, I decided to give PyAudio a try. First of all, I needed to install PyAudio.

Installing PyAudio

At the time of this writing, the latest version of PyAudio is v0.2.9, and the PyAudio team has made the installation as simple as possible.

Installing OpenCV from source on Anaconda Python on Ubuntu 16.10

I recently switched to Linux for my Machine Learning experiments, and I did a post on How to install Keras and Anaconda Python on Ubuntu 16.10.

Now, I wanted to install OpenCV on Ubuntu also. Since OpenCV does not have a pre-built package for Linux, it meant I had to compile OpenCV from source.

OpenCV 3.1 running on Lubuntu 16.10

Adrian of PyImageSearch has recently done a post about how to compile OpenCV on Ubuntu 16.04 using virtualenv. I followed his steps as a base, but had to make numerous adjustments to some of the packages which gets installed (e.g. libpng-dev, libhdf5-serial-dev) and the build commands due to the changes from Ubuntu 16.04 to 16.10, and because I'm using Anaconda environments rather than virtualenv.

I'll be installing OpenCV 3.1, and will be using the Lubuntu 16.10 virtual machine which I used in my earlier post. But the steps and commands will be exactly the same for any flavor of Ubuntu 16.10.

First, as a habit, get and install the latest updates for Ubuntu,

 sudo apt-get update   
 sudo apt-get upgrade   

Then (if you have not done already) install the necessary build tools,

 sudo apt-get install build-essential cmake git unzip pkg-config  

Then, we install the following packages which allows OpenCV to interact with various image and video formats,

 sudo apt-get install libjpeg8-dev libtiff5-dev libjasper-dev libpng-dev  
 sudo apt-get install libavcodec-dev libavformat-dev libswscale-dev libv4l-dev  
 sudo apt-get install libxvidcore-dev libx264-dev  

Note: on Ubuntu 16.04, the package name for libpng was libpng12-dev. But on 16.10, it should be libpng-dev.

Getting the LeNet model working with Face Recognition

In my last post, I talked about how the LeNet Convolutional Neural Network model is capable of handling much more complex data than the intended MNIST dataset. We saw how it got ~99% accuracy when it learned to identify 10 faces from the raw pixel intensities.

So, let’s see the code I used to get it working.

First of all, I needed a training dataset. For that, I created a set of face images of 10 subjects with around 500 images each.

The training dataset (yep, that's my face)

I use a file naming convention as <subject_label>-<subject_name>-<unique_number>.jpg (e.g. 0-Thimira-1475137898.65.jpg) for the training images to make it easier to read in and get the metadata of the images in one go. (I will do a separate post on how to easily create training datasets of face images like this).

We'll mainly be using Keras to build the model, and scikit-learn for some utility functions. We’ll need to import the following packages,

 from sklearn.cross_validation import train_test_split  
 from keras.optimizers import SGD  
 from keras.utils import np_utils  
 import numpy as np  
 import argparse  
 import cv2  
 import os  
 import sys  
 from PIL import Image  

Switching between TensorFlow and Theano on Keras

Keras speeds up the task of building Neural Networks by providing high-level simplified functions to create and manipulate neural models. It itself does not provide the lower level neural and deep learning functions, but it’s rather meant to be run on an engine – which Keras refers to as a “backend” - which would provide such low-level functions.

Currently, Keras supports two such backends – TensorFlow and Theano.

The current version of Keras (v1.1.0 at the time of this writing) uses TensorFlow by default.

Most models written on top of Keras can be switched to a different backend without changes – at least it’s what’s said in the documentation. I’m yet to test this.

Which backend Kesas will use is defined in the Keras config file, which is located in the .keras directory in your home directory:
e.g.: on linux it would be ~/.keras/keras.json and on windows you can get to it on %USERPROFILE%\.keras\keras.json

For the default of using the TensorFlow backend, use the following config,

 {  
   "image_dim_ordering": "tf",  
   "epsilon": 1e-07,  
   "floatx": "float32",  
   "backend": "tensorflow"  
 }  

Notice the "backend" is set to "tensorflow" and "image_dim_ordering" is set to "tf".

To use the Theano backend, use the following,

 {  
   "image_dim_ordering": "th",   
   "epsilon": 1e-07,   
   "floatx": "float32",   
   "backend": "theano"  
 }  

Apart from the obvious "backend": "theano", note that "image_dim_ordering" is set to "th".

See my new post to see what the image_dim_ordering parameter in Keras does, and why is it important to set it properly.

Update: If you use Jupyter notebooks, and need to switch between TensorFlow and Theano backends quite often, fellow blogger desertnaut has a solution to dynamically switch the backend. Check out his solution at: Dynamically switch Keras backend in Jupyter notebooks

Related posts:
What is the image_dim_ordering parameter in Keras, and why is it important

Related links:
https://keras.io/backend/

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Getting Dlib Face Landmark Detection working with OpenCV

Dlib has excellent Face Detection and Face Landmark Detection algorithms built-in. Its face detection is based on Histogram of Oriented Gradients (HOG) feature combined with a linear classifier, on a sliding window detection scheme (Ref. http://dlib.net/) and it provides pre-trained models for face landmark detection. It also provides handy utility functions like dlib.get_frontal_face_detector() to make our lives easier.

Dlib Face Landmark Detection in action

Note: Image used for testing is in the Public Domain - https://en.wikipedia.org/wiki/File:Arnold_Schwarzenegger_edit%28ws%29.jpg

To check out Dlib with it's native functions, you can try out the Dlib example from the official site: http://dlib.net/face_landmark_detection.py.html.It works well, but we can do better.

Although Dlib offers all the simplicity in implementing face landmark detection, it's still no match for the flexibility of OpenCV. (Simply put, Dlib is a library for Machine Learning, while OpenCV is for Computer Vision and Image Processing)

So, can we use Dlib face landmark detection functionality in an OpenCV context? Yes, here's how.

Installing Dlib on Anaconda Python on Windows

Update - 16/Dec/2019: There is now an easier way to install Dlib from the official pip package. Check out the new tutorial How to Build and Install the Latest Version of Dlib on Anaconda on Windows

Dlib is a Machine Learning library, primarily written in C++, but has a Python package also. It has many useful and optimized algorithms useful for machine learning, linear algebra, data structures, image processing, and much more available out-of-the-box.

"Dlib is a modern C++ toolkit containing machine learning algorithms and tools for creating complex software in C++ to solve real world problems. It is used in both industry and academia in a wide range of domains including robotics, embedded devices, mobile phones, and large high performance computing environments. Dlib's open source licensing allows you to use it in any application, free of charge." - dlib.net

One of the most popular features in Dlib is Facial Landmark Detection. Dlib installation ships with a pre-trained shape predictor model named shape_predictor_68_face_landmarks.dat, which as the name suggests, is trained to detect 68 facial keypoints including eyes, eyebrows, mouth, nose, face outline, etc.

Dlib's Facial Landmark Detection in action

You can view the sample code for face landmark detection here at the Dlib website, and download the pre-trained model from http://dlib.net/files/shape_predictor_68_face_landmarks.dat.bz2

(Make sure to unzip the .bz2 file once you download it)

Of course, Dlib is capable of much more than face landmark detection. I'm hoping to dig into some cool features of Dlib in later posts.

But first, we need to install it.

Getting Keras working with Anaconda Python

I've started using the Anaconda Python distribution for most of my Machine Learning. It has pre-built binaries of Python for many platforms and architectures, has hundreds of pre-built and tested Python packages directly available through the conda package manager, and it allows easy creation of virtual isolated environments - with its own Python version and packages - to experiment with.

You can get an idea of the capabilities of Anaconda by going through their Anaconda Test Drive guide.

Getting Keras (with Theano backend) working on any Python distribution is usually straightforward, but you do run into some errors occasionally based on the platform you're on and your environment settings.

So, here are the steps that worked for me to get Keras working on the Anaconda Python distribution:

First, you need to install Anaconda. It's as easy as getting the binary for your platform from Anaconda download page and running it. Once it's installed, the conda command will be available from your terminal or command prompt.

Now you can create an anaconda environment to install Keras and related packages,

 conda create --name keras-test numpy scipy scikit-learn pillow h5py mingw libpython  

'keras-test' is the name of the environment we're creating. You can give it a different name.
You can also create an environment with a different Python version. For example, if you want to create the environment with Python 2.7,

 conda create --name keras-test python=2.7 numpy scipy scikit-learn pillow h5py mingw libpython  

Once the environment is created, activate it.

 activate keras-test  

Then, we'll install Theano from Git, since we want the latest development version,

 pip install --upgrade --no-deps git+git://github.com/Theano/Theano.git  

And then, we install Keras from PIP,

 pip install keras  

Finally, we setup OpenBLAS and configure Theano to use it. My earlier blog post - Getting Theano working with OpenBLAS on Windows - details how to setup Theano with OpenBLAS in detail.

We can test whether the setup was successful by running the Python interpreter and importing Keras package,

 python  
 >>> import keras  
 Using Theano backend.  

Keras loading successfully

If you don't get any errors when the Keras package is loading, then all is set.

Related posts:
Switching between TensorFlow and Theano on Keras
What is the image_dim_ordering parameter in Keras, and why is it important

Related Links:
https://www.continuum.io/downloads
https://docs.continuum.io/anaconda/pkg-docs
http://conda.pydata.org/docs/test-drive.html

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Working Theano configs

Here are the Theano configurations that I have tested and worked.
These were tested on Windows 10 64-Bit, and Windows 7 64-Bit.
(I will update when I test on other OS's and setups)

With GPU support, on CUDA and cuDNN

In order to allow Theano to use the GPU, you need to be on a machine with a supported Nvidia GPU, and have the CUDA toolkit and cuDNN setup. I will cover how to setup CUDA on a different post.

 [global]  
 floatX = float32  
 device = gpu  
   
 [nvcc]  
 flags=-LC:\Users\Thimira\Anaconda3  
 compiler_bindir=C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\bin  
   
 [dnn]  
 enabled = True  
   
 [lib]  
 cnmem=0.75  
   
 [blas]   
 ldflags=-LC:\Dev_Tools\openblas\bin -lopenblas  

device = gpu tells Theano to use the GPU instead of the CPU.
flags=-LC:\Users\Thimira\Anaconda3 point this to your Python installation (I'm using Anaconda Python)
compiler_bindir=C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\bin point this to the bin dir of your Visual Studio installation (Note: CUDA only worked with Visual Studio 2013 for me)
[dnn] enabled = True this enables cuDNN
cnmem=0.75 set the memory limit Theano can use of the GPU. Here it's set to 75% of the GPU memory
ldflags=-LC:\Dev_Tools\openblas\bin -lopenblas point to your OpenBLAS installation. Refer to my earlier post Getting Theano working with OpenBLAS on Windows

With only CPU support

Since not everyone have a compatible Nvidia GPU to have CUDA.

 [global]  
 floatX = float32  
 device = cpu  
   
 [blas]  
 ldflags=-LC:\Dev_Tools\openblas\bin -lopenblas  

device = cpu tells Theano to use the CPU.
ldflags=-LC:\Dev_Tools\openblas\bin -lopenblas point to your OpenBLAS installation. Refer to my earlier post Getting Theano working with OpenBLAS on Windows

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Getting Theano working with OpenBLAS on Windows

I wanted to try out Machine Learning with Python, so my first choice was Keras with Theano.

Got Theano installed from Git (to get the latest development version):

 pip install --upgrade --no-deps git+git://github.com/Theano/Theano.git  

Then, I needed to setup Theano with OpenBLAS (otherwise, training Keras models was painfully slow).
Since I was on Windows, I had to look around for instructions on how to setup OpenBLAS properly.

Luckily, OpenBLAS provides binaries for Windows - both 32Bit and 64Bit - although, they may not be for the latest version of OpenBLAS.

Head over to https://sourceforge.net/projects/openblas/files/ and see which release has the binaries already built for Windows. We need both OpenBLAS and MinGW binaries.

At the time of this writing the latest version of OpenBLAS was v0.2.19, which unfortunately doesn't have the Windows binaries released.

But, going back a few releases, we find that the release v0.2.15 includes the binaries - OpenBLAS-v0.2.15-Win64-int32.zip and mingw64_dll.zip.

Download both of the Zip files, and first extract the OpenBLAS Zip to a globally accessible location on your hard disk. (I would suggest a location such as C:\Dev_Tools\openblas\).
Then, extract the mingw Zip, and copy it's contents to the bin directory of your extracted OpenBLAS directory. e.g. If you extracted OpenBLAS to C:\Dev_Tools\openblas\, then copy the contents (3 DLL files) of mingw to C:\Dev_Tools\openblas\bin\.
i.e.: The extracted openblas\bin will have the libopenblas.dll in it. When you extract mingw, it will have 3 more DLLs - libgcc_s_seh-1.dll, libgfortran-3.dll, libquadmath-0.dll. Copy those to openblas\bin also.

Then, add the openblas\bin directory to your system path.

Finally, edit (or create) your .theanorc file with the following settings: (assuming you extracted OpenBLAS to C:\Dev_Tools\openblas\)
Note: If you don't already have a .theanorc file, create a file named .theanorc in the home directory of your user account, e.g. C:\Users\<your user>\.theanorc

 [global]  
 floatX = float32  
 device = cpu  
   
 [blas]  
 ldflags=-LC:\Dev_Tools\openblas\bin -lopenblas  

Now, run your Keras/Theano program and see whether Theano picks up OpenBLAS.


Related Links:
http://www.openblas.net/

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