Deep Learning
–
A hands-on introduction to image classification
Immanuel Weber, University of Applied Sciences Koblenz
2019/05/21
Deep Learning?
(Deep) Neural Networks
The ImageNet Moment
(patrykchrabaszcz.github.io/Imagenet32)
ImageNet is dataset of more than 14M
images and more than 20k categories
(ImageNet Performance: nvidia.com)
AlexNet
ResNet-34
residual connections
AlexNet: 60M parameters
ResNet-34: 21M parameters
Thanks to the gamers we got…
(LAN Party: wikipedia.org)
NVIDIA DGX-2 (nvidia.com)(Tesla Performance: nvidia.com)
Let’s classify beer and pizza…
(Pizza, Beer: wikipedia.org)
sigmoid
ReLU
w1
w2
w3
Σ
+ b
Single artificial neuron
pizza?
color
size
shape
color
size
shape
pizza
beer
Slighlty simplified, as biases and activation functions are omitted
Simple neural network
x W1 W2 W3 y
Slighlty simplified, as biases and activation functions are omitted
Simple neural network
x W1 W2 W3 y
• • • =
Slighlty simplified, as biases and activation functions are omitted
Simple neural network
Deep neural networks are just
networks with many layers.
convolution
kernel
○ =
Σ
Convolutions
convolution
kernels
* =
Convolutions
convolution
kernels
Convolutions
residual connections
convolutional layers
fully
connected
layer
pizza
beer
Beer & Pizza Classifier
Simple math, however…
weights, biases and kernels
are unkown.
0.8
0.2
(Pizza: wikipedia.org)
Beer & Pizza Classifier
0.55
0.45
(Beer: wikipedia.org)
Beer & Pizza Classifier
inputs
labels/targets
Beer
Pizza
Beer
Pizza
Pizza
Pizza
Beer
Beer
Beer
…
Beer & Pizza Dataset
(Pizzas, Beers: wikipedia.org)
(Pizzas, Beers: wikipedia.org)
Beer & Pizza Classifier
Pizza
Beer
Beer
Pizza
Beer
Pizza
Pizza
Pizza
Beer
…
outputs labels
Beer
Pizza
Beer
Pizza
Pizza
Pizza
Beer
Beer
Beer
…
loss function
Simplified: outputs are not discrete labels
Backpropagation
+ optimizer
Iterating over datasets and optimizing values
still takes a long time
Don‘t start from the beginning…
use pretrained networks
and do transfer learning.
Demo.
Thank you.

Deep Learning - A hands-on introduction to image classification