Theano

Colour image classification (CIFAR-10) using a CNN

As I mentioned in a previous post, a convolutional neural network (CNN) can be used to classify colour images in much the same way as grey scale classification. The way to achieve this is by utilizing the depth dimension of our input tensors and kernels. In this example I’ll be using the CIFAR-10 dataset, which … Read moreColour image classification (CIFAR-10) using a CNN

Visualizing Convolutional Neural Networks using nolearn

We previously talked about Convolutional Neural Networks (CNN) and how use them to recognize handwritten digits using Lasagne. While we can manually extract kernel parameters to visualize weights and activation maps (as discussed in the previous post), the nolearn package offers an easy way to visualize different elements of CNNs. nolearn is a wrapper around Lasagne … Read moreVisualizing Convolutional Neural Networks using nolearn

Handwritten digit recognition with a CNN using Lasagne

Following my overview of Convolutional Neural Networks (CNN) in a previous post, now lets build a CNN model to 1) classify images of handwritten digits, and 2) see what is learned by this type of model. Handwritten digit recognition is the ‘Hello World’ example of the CNN world. I’ll be using the MNIST database of … Read moreHandwritten digit recognition with a CNN using Lasagne

XOR Logic Gate – Neural Networks

We have previously discussed OR logic gates and the importance of bias units in AND gates. Here, we will introduce the XOR gate and show why logistic regression can’t model the non-linearity required for this particular problem. As always, the full code for these examples can be found in my GitHub repository here. XOR gates … Read moreXOR Logic Gate – Neural Networks

AND Logic Gate – Importance of bias units

Previously, we talked about simple OR gates and now we’ll continue that discussion with AND gates, and specifically the role of bias units. We often neglect to consider the role bias plays in our models. We know that we should include bias units, but why? Here, I’ll walk through a short example using an AND … Read moreAND Logic Gate – Importance of bias units

OR Logic Gate using Theano

Theano is a powerful Python library that provides some useful tools for machine learning, such as GPU training and symbolic differentiation of the cost function during gradient descent. It can be a bit challenging to understand how Theano works, so before jumping into more complex non-linear models, we can get to grips with Theano by … Read moreOR Logic Gate using Theano