CIlib - A software library for compressive imaging

This repository contains a broad set of functions and tools for experimenting with various compressive imaging reconstruction techniques. It is meant as a companion to the book Compressive imaging: Structure, Sampling, Learning by Ben Adcock and Anders C. Hansen (Cambridge University Press, 2020), and can be used to reproduce most of the figures presented in the book. The code has been developed by Vegard Antun (see acknowledgement section for details).

Getting started

Paths, data, and default values

As with any toolbox in MatLab it is important to add the right paths to your MatLab session. To do this automatically when starting MatLab, you can try to run the install_cilib.m file. This script will locate your startup.m file, and append the necessary lines to this file. If not, you can also manually add the necessary paths by running the lines below.

path_to_cilib_dir = pwd;
addpath(fullfile(path_to_cilib_dir, 'src', 'samp_patt'));
addpath(fullfile(path_to_cilib_dir, 'src', 'utils'));
addpath(fullfile(path_to_cilib_dir, 'src', 'var'));
clear path_to_cilib_dir

Make sure to modify the pwd argument if you are not running this from the CIlib directory.

The test images used in the figures can be downloaded here (347 MB).

To ensure that font sizes, colours etc., are consistent between all the figures, we define a set of default variables in etc/set_defaults.m. This file will create the file 'var/cilib_defaults.mat', with the chosen default parameters. This file is read by all scripts producing figures for the book. Thus to run the code successfully, it is required to run the set_defaults.m file once, to produce the file cilib_defaults.mat. Make sure you you modify the cil_dflt.data_path in the set_defaults.m file, so that it points to the directory with the test images.

Dependencies

It is required to install the following packages.

SPGL1 A solver for large-scale sparse reconstruction
NESTA A Fast and Accurate First-order Method for Sparse Recovery (in particular TV minimization).
Fastwht A fast implementation of of matlabs fwht-function (Optional, but recommended).
ShearLab Shearlets (ShearLab3D v1.1)
CurveLab Curvelets (CurveLab 2.1.3)
ShearletReweighting Iterative reweighing strategy described in Chapter 4.6.

Note on wavelet boundary handling

By default, MatLab does not use periodic wavelets. For all the scripts in this library, it is assumed that the periodic wavelet extension is used. Thus many of the scripts call the function dwtmode('per', 'nodisp'), which changes the default wavelet extension in a MatLab session without notifying the user. Be aware of this behaviour, and explicitly change the wavelet extension back again if required.

Overview of the code

All the code is located in the src directory. Within this directory, we find the following directories.

src/utils: Contain all functions used to create the figures
src/samp_patt: Contain code to generate all the sampling patterns.
src/misc: Code from various other toolboxes.
src/chX: Code to generate figures in chapter X. See the README.md file within each directory for details on which figure the scripts create.

Citing

To cite the book, please use

@book{adcock2020compressive,
	Author = {Ben Adcock and Anders C. Hansen},
	Publisher = {Cambridge University Press},
	Title = {Compressive Imaging: Structure, Sampling, Learning},
	Year = {2020}
}

and to cite the code, please use

@misc{CIlib,
	Author = {Vegard Antun},
	Year = {2020},
	Title = {{CI}lib --  A software library for compressive imaging},
	note = {https://github.com/vegarant/cilib},
}

Acknowledgments

First and foremost, I need to thank Ben Adcock and Anders Hansen, without whom this code would never have existed. It has taken numerous iterations back and forth between the three of us to produce the desired images for the book. I would like to thank Kristian Monsen Haug, for coding up the backend used for all of the multilevel Gaussian sampling patterns. I want to thank Edvard Aksnes, for coding up functions to reorder wavelet coefficients and the first version of the scripts producing Figures 1.3 and 4.10. Initially, I planned to host this code its own webpage. A few years ago, Mathias Lohne, therefore, created a skeleton for such a webpage from scratch. In the end, I decided it was easier and better to use Github, but I would like to thank Mathias for the effort he put into this.

vegarant / cilib