Introduction to Deep Learning


Figure 1

Three nested circles defining deep learning as a subset of machine learning which is a subset of artifical intelligence
The image above is by Tukijaaliwa, CC BY-SA 4.0, via Wikimedia Commons, original source

Figure 2

Four types of image classification tasks include semantic segmentation to label every pixel; classification and localisation to detect a single object like a cat; object detection to detect multiple objects like cats and dogs; and instance segmentation to detect each pixel of multiple objects
The image above is by Li, Johnson, & Yeung, Stanford University CS231n: Deep Learning for Computer Vision, 2017

Figure 3

Subset of 25 CIFAR-10 images representing different object classes

Figure 4

poor resolution image of a cat

Introduction to Image Data


Figure 1

Jabiru image that is 552 pixels wide and 573 pixels high. A red square around the neck region indicates the area to zoom in on.

Figure 2

zoomed in area of Jabiru where the individual pixels stand out

Figure 3

Screenshot of Spyder window displaying the entire train_labels array.

Build a Convolutional Neural Network


Figure 1

diagram of a single neuron taking multiple inputs and their associated weights in and then applying an activation function to predict a single output

Figure 2

diagram of a neural with four neurons taking multiple inputs and their weights and predicting multiple outputs
The image above is by Glosser.ca, CC BY-SA 3.0, via Wikimedia Commons, original source

Figure 3

6x5 input matrix representing a single colour channel image being multipled by a 3x3 kernel to produce a 4x4 output matrix to detect horizonal edges in an image

Figure 4

single colour channel image of a cat multiplied by a 3x3 kernel to produce an image of a cat where the edges  stand out

Figure 5

diagram of a neural network with multiple inputs feeding into to two seperate dense layers with connections between all the inputs and outputs

Compile and Train (Fit) a Convolutional Neural Network


Figure 1

Plot of loss over weight value illustrating how a small learning rate takes a long time to reach the optimal solution.
Small learning rate leads to inefficient approach to loss minima

Figure 2

Plot of loss over weight value illustrating how a large learning rate never approaches the optimal solution because it bounces between the sides.
A large learning rate results in overshooting the gradient descent minima

Figure 3

Plot of loss over weight value illustrating how a good learning rate gets to optimal solution gradually.
An optimal learning rate supports a gradual approach to the minima

Figure 4

two panel figure; the figure on the left illustrates the training loss starting at 1.5 and decreasing to 0.7 and the validation loss decreasing from 1.3 to 1.0 before leveling out; the figure on the right illustrates the training accuracy increasing from 0.45 to 0.75 and the validation accuracy increasing from 0.53 to 0.65 before leveling off

Figure 5

diagram of two neural networks; the first network is densely connected without dropout and the second network has some of the neurons dropped out of of the network

Figure 6

two panel figure; the figure on the left illustrates the training loss starting at 1.7 and decreasing to 1.0 and the validation loss decreasing from 1.4 to 0.9 before leveling out; the figure on the right illustrates the training accuracy increasing from 0.40 to 0.65 and the validation accuracy increasing from 0.5 to 0.67

Evaluate a Convolutional Neural Network and Make Predictions (Classifications)


Figure 1

for ten classes an example confusion matrix has 10 rows and 10 columns where the value in each cell is the number of observations predicted in that class and known to be in that class. The diagonal cells are where the true and predicted classes match.

Figure 2

Confusion matrix of model predictions where the colour scale goes from black to light to represent values from 0 to the total number of test observations in our test set of 1000. The diagonal has much lighter colours, indicating our model is predicting well, but a few non-diagonal cells also have a lighter colour to indicate where the model is making a large number of prediction errors.

Figure 3

test loss plotted against five dropout rates ranging from 0.15 to 0.75 where the minimum test loss appears to occur between 0.4 and 0.5

Figure 4

Validation accuracy plotted against ten epochs for five different activations functions. relu and Leaky relu have the highest accuracy atound 0.60; sigmoid and selu are next with accuracy around 0.45 and tanh has the lowest accuracy of 0.35

Share a Convolutional Neural Network and Next Steps