cryoCARE-mpido 0.2

cryoCARE is a deep learning approach for cryo-TEM tomogram denoising.

cryoCARE (MPI Dortmund Edition)

This package is a fork of a memory efficient implementation of cryoCARE.

Compared to the original implementation, the "MPI Dortmund" edition contains the following changes:

• cyroCARE_train produces new, compressed and more protable model. This model can be copied and shared with others without relying on a certain folder structure.
• cryoCARE_predict supports to predict multiple tomograms in one run. Streamlined with respect to the changes of cryoCARE_train.
• Streamlined installation instructions
• Minor changes/ fixed couple of bugs:
  • Proper padding of tomograms to avoid black frames in the denoised tomograms
  • Fix computation of validation cut off for small tomograms

This setup trains a denoising U-Net for tomographic reconstruction according to the Noise2Noise training paradigm. Therefor the user has to provide two tomograms of the same sample. The simplest way to achieve this is with direct-detector movie-frames. These movie-frames can be split in two halves (e.g. with MotionCor2 -SplitSum 1 or with IMOD alignframes -debug 10000) from which two identical, up to random noise, tomograms can be reconsturcted. These two (even and odd) tomograms can be used as input to this cryoCARE implementation.

Installation

Note: We assume that you have miniconda installed.

Create a the following conda environment with: conda create -n cryocare -c conda-forge -c anaconda python=3 keras-gpu=2.3.1

Then activate it with: conda activate cryocare

Then you can install cryoCARE with pip: pip install cryoCARE_mpido

Manual

cryoCARE uses .json configuration files and is run in three steps:

1. Prepare Training Data

To prepare the training data we have to provide all tomograms on which we want to train. Create an empty file called train_data_config.json, copy-paste the following template and fill it in.

{
  "even": [
    "/path/to/even.rec"
  ],
  "odd": [
    "/path/to/odd.rec"
  ],
  "patch_shape": [
    72,
    72,
    72
  ],
  "num_slices": 1200,
  "split": 0.9,
  "tilt_axis": "Y",
  "n_normalization_samples": 500,
  "path": "./"
}

Parameters:

• "even": List of all even tomograms.
• "odd": List of all odd tomograms. Note the order has to be the same as in "even".
• "patch_shape": Size of the sub-volumes used for training. Should not be smaller than 64, 64, 64.
• "num_slices": Number of sub-volumes extracted per tomograms.
• "tilt_axis": Tilt-axis of the tomograms. We split the tomogram along this axis to extract train- and validation data separately.
• "n_normalization_samples": Number of sub-volumes extracted per tomograms, which are used to compute mean and standard deviation for normalization.
• "path": The training and validation data are saved here.

Run Training Data Preparation:

After installation of the package we have access to built in Python-scripts which we can call. To run the training data preparation we run the following command: cryoCARE_extract_train_data.py --conf train_data_config.json

2. Training

Create an empty file called train_config.json, copy-paste the following template and fill it in.

{
  "train_data": "./",
  "epochs": 100,
  "steps_per_epoch": 200,
  "batch_size": 16,
  "unet_kern_size": 3,
  "unet_n_depth": 3,
  "unet_n_first": 16,
  "learning_rate": 0.0004,
  "model_name": "model_name",
  "path": "./"
}

Parameters:

• "train_data": Path to the directory containing the train- and validation data. This should be the same as the "path" from above.
• "epochs": Number of epochs used to train the network.
• "steps_per_epoch": Number of gradient steps performed per epoch.
• "batch_size": Used training batch size.
• "unet_kern_size": Convolution kernel size of the U-Net. Has to be an odd number.
• "unet_n_depth": Depth of the U-Net.
• "unet_n_first": Number of initial feature channels.
• "learning_rate": Learning rate of the model training.
• "model_name": Name of the model.
• "path": Output path for the model.

Run Training:

To run the training we run the following command: cryoCARE_train.py --conf train_config.json

You will find a .tar.gz file in the directory you specified as path. This your model an will be used in the next step.

3. Prediction

Create an empty file called predict_config.json, copy-paste the following template and fill it in.

{
  "path": "path/to/your/model.tar.gz",
  "even": "/path/to/even/tomos/",
  "odd": "/path/to/odd/tomos/",
  "n_tiles": [1, 1, 1],
  "output": "/path/to/output/folder/"
}

Parameters:

• "path": Path to your model file.
• "even": Path to directory with even tomograms or a specific even tomogram.
• "odd": Path to directory with odd tomograms or a specific odd tomogram.
• "n_tiles": Initial tiles per dimension. Gets increased if the tiles do not fit on the GPU.
• "output": Path where the denoised tomograms will be written.

Run Prediction:

To run the training we run the following command: cryoCARE_predict.py --conf predict_config.json

How to Cite

@inproceedings{buchholz2019cryo,
  title={Cryo-CARE: content-aware image restoration for cryo-transmission electron microscopy data},
  author={Buchholz, Tim-Oliver and Jordan, Mareike and Pigino, Gaia and Jug, Florian},
  booktitle={2019 IEEE 16th International Symposium on Biomedical Imaging (ISBI 2019)},
  pages={502--506},
  year={2019},
  organization={IEEE}
}

@article{buchholz2019content,
  title={Content-aware image restoration for electron microscopy.},
  author={Buchholz, Tim-Oliver and Krull, Alexander and Shahidi, R{\'e}za and Pigino, Gaia and J{\'e}kely, G{\'a}sp{\'a}r and Jug, Florian},
  journal={Methods in cell biology},
  volume={152},
  pages={277--289},
  year={2019}
}