LenslessPiCam

A Hardware and Software Toolkit for Lensless Computational Imaging

This toolkit has everything you need to perform imaging with a lensless camera. The sensor in most examples is the Raspberry Pi HQ, camera sensor as it is low cost (around 50 USD) and has a high resolution (12 MP). The lensless encoder/mask used in most examples is either a piece of tape or a low-cost LCD. As modularity is a key feature of this toolkit, we try to support different sensors and/or lensless encoders.

The toolkit includes:

• Camera assembly tutorials (link).
• Measurement scripts (link).
• Dataset preparation and loading tools, with Hugging Face integration (slides on uploading a dataset to Hugging Face with this script).
• Reconstruction algorithms (e.g. FISTA, ADMM, unrolled algorithms, trainable inversion, pre- and post-processors).
• Training script for learning-based reconstruction.
• Pre-trained models that can be loaded from Hugging Face, for example in this script.
• Mask design and fabrication tools.
• Simulation tools.
• Evalutions tools (e.g. PSNR, LPIPS, SSIM, visualizations).
• Demo that can be run on Telegram!

Please refer to the documentation for more details, while an overview of example notebooks can be found here.

We've also written a few Medium articles to guide users through the process of building the camera, measuring data with it, and reconstruction. They are all laid out in this post.

Setup

If you are just interested in using the reconstruction algorithms and plotting / evaluation tools you can install the package via pip:

pip install lensless

For plotting, you may also need to install Tk.

For performing measurements, the expected workflow is to have a local computer which interfaces remotely with a Raspberry Pi equipped with the HQ camera sensor (or V2 sensor). Instructions on building the camera can be found here.

The software from this repository has to be installed on both your local machine and the Raspberry Pi. Note that we highly recommend using Python 3.9, as some Python library versions may not be available with earlier versions of Python. Moreover, its end-of-life is Oct 2025.

Local machine setup

Below are commands that worked for our configuration (Ubuntu 21.04), but there are certainly other ways to download a repository and install the library locally.

# download from GitHub
git clone git@github.com:LCAV/LenslessPiCam.git
cd LenslessPiCam

# create virtual environment (as of Oct 4 2023, rawpy is not compatible with Python 3.12)
# -- using conda
conda create -n lensless python=3.11
conda activate lensless

# -- OR venv
python3.11 -m venv lensless_env
source lensless_env/bin/activate

# install package
pip install -e .

# extra dependencies for local machine for plotting/reconstruction
pip install -r recon_requirements.txt

# (optional) try reconstruction on local machine
python scripts/recon/admm.py

# (optional) try reconstruction on local machine with GPU
python scripts/recon/admm.py -cn pytorch

Note (25-04-2023): for using the :py~lensless.recon.apgd.APGD reconstruction method based on Pycsou (now Pyxu), a specific commit has to be installed (as there was no release at the time of implementation):

pip install git+https://github.com/matthieumeo/pycsou.git@38e9929c29509d350a7ff12c514e2880fdc99d6e

If PyTorch is installed, you will need to be sure to have PyTorch 2.0 or higher, as Pycsou is not compatible with earlier versions of PyTorch. Moreover, Pycsou requires Python within [3.9, 3.11).

Moreover, numba (requirement for Pycsou V2) may require an older version of NumPy:

pip install numpy==1.23.5

Raspberry Pi setup

After flashing your Raspberry Pi with SSH enabled, you need to set it up for passwordless access. Do not set a password for your SSH key pair, as this will not work with the provided scripts.

On the Raspberry Pi, you can then run the following commands (from the home directory):

# dependencies
sudo apt-get install -y libimage-exiftool-perl libatlas-base-dev \
python3-numpy python3-scipy python3-opencv
sudo pip3 install -U virtualenv

# download from GitHub
git clone git@github.com:LCAV/LenslessPiCam.git

# install in virtual environment
cd LenslessPiCam
virtualenv --system-site-packages -p python3 lensless_env
source lensless_env/bin/activate
pip install --no-deps -e .
pip install -r rpi_requirements.txt

# test on-device camera capture (after setting up the camera)
source lensless_env/bin/activate
python scripts/measure/on_device_capture.py

You may still need to manually install numpy and/or scipy with pip in case libraries (e.g. libopenblas.so.0) cannot be detected.

Acknowledgements

The idea of building a lensless camera from a Raspberry Pi and a piece of tape comes from Prof. Laura Waller's group at UC Berkeley. So a huge kudos to them for the idea and making tools/code/data available! Below is some of the work that has inspired this toolkit:

• Build your own DiffuserCam tutorial.
• DiffuserCam Lensless MIR Flickr dataset¹.

A few students at EPFL have also contributed to this project:

• Julien Sahli: support and extension of algorithms for 3D.
• Yohann Perron: unrolled algorithms for reconstruction.
• Aaron Fargeon: mask designs.
• Rein Bentdal: mask fabrication with 3D printing.

Citing this work

If you use these tools in your own research, please cite the following:

@article{Bezzam2023,
   doi = {10.21105/joss.04747},
   url = {https://doi.org/10.21105/joss.04747},
   year = {2023},
   publisher = {The Open Journal},
   volume = {8},
   number = {86},
   pages = {4747},
   author = {Eric Bezzam and Sepand Kashani and Martin Vetterli and Matthieu Simeoni},
   title = {LenslessPiCam: A Hardware and Software Platform for Lensless Computational Imaging with a Raspberry Pi},
   journal = {Journal of Open Source Software}
}

References

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1. Monakhova, K., Yurtsever, J., Kuo, G., Antipa, N., Yanny, K., & Waller, L. (2019). Learned reconstructions for practical mask-based lensless imaging. Optics express, 27(20), 28075-28090.↩