Convolutional neural network practical (2)

A computer vision practical by the Oxford Visual Geometry group, authored by Andrea Vedaldi, Karel Lenc, and Joao Henriques.

Start from doc/instructions.html.

Note that this practical requires compiling the (included) MatConvNet library. This should happen automatically (see the setup.m script), but make sure that the compilation succeeds on the laboratory computers.

Package contents

The practical consists of four exercises, organized in the following files:

• exercise1.m -- Part 1: Building blocks: convolution and ReLU
• exercise2.m -- Part 2: Derivatives and backpropagation
• exercise3.m -- Part 3: Learning a CNN for text deblurring

The practical runs in MATLAB and uses MatConvNet. This package contains the following MATLAB functions:

• checkDerivativeNumerically.m: check a layer derivatives numerically.
• customLayerForward.m and customLayerBackward.m: code (partially) implementing a custom layer.
• getBatch.m:: get a batch of images for training.
• getCustomLayer.m: get the custom layer in SimpleNN format.
• initializeSmallCNN.m and initializeLargeCNN.m: initialize CNN models for text deblurring.
• setup.m: setup MATLAB environment.
• showDeblurringResult.m: show results for the deblurring network.
• showFeatureChannels.m: show the feature channels in a tensor.
• xavier.m: Xaiver's initialization of the network weights.

Appendix: Installing from scratch

The practical requires both VLFeat and MatConvNet. VLFeat comes with pre-built binaries, but MatConvNet does not.

0. Set the current directory to the practical base directory.
1. From Bash:
   1. Run git submodule update -i to download the submodules.
   2. Run make -f ./extras/Makefile preproc. This will create a copy of the data for the practical
2. From MATLAB run addpath extra ; preprocess ;. This will create data/text_imdb.mat.
3. Test the practical: from MATLAB run all the exercises in order.

Changes

• 2016a - Initial edition

License

Copyright (c) 16 Andrea Vedaldi, Karel Lenc, and Joao Henriques

Permission is hereby granted, free of charge, to any person
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The above copyright notice and this permission notice shall be
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