Denoising Autoencoder for Auroral Radio Emissions

Table of Contents

1. About
2. Approach
3. Usage
4. Command Line Arguments
5. API Tutorial
6. Citation

About

The Denoising Autoencoder for Auroral Radio Emissions (DAARE) is a tool to remove Radio Frequency Interference (RFI) commonly emerging as horizontal emission lines from time-frequency spectrograms. This tool was built to denoise Auroral Kilometric Radiation (AKR) observations from the South Pole Station.

This work was generously supported by National Science Foundation grant AST-1950348, conducted at the MIT Haystack Observatory REU 2022 by Allen Chang, and advised by Mary Knapp.

Approach

Usage

1. Install required packages.

pip install -r requirements.txt

2. To train a new model, run train.py.
3. To use a pretrained model, use api.py.

Command Line Arguments

train.py

Paths

--path_to_data: Path to the data directory.

--path_to_logs: Path to the logs directory.

--path_to_output: Path to the output directory.

Run options

--model_name: Name of the model when logging and saving.

--verbose: Trains with debugging outputs and print statements.

--tqdm_format: Flag bar_format for the TQDM progress bar.

--disable_logs: Disables logging to the output log directory.

--refresh_brushes_file: Rereads brush images and saves them to the loaded CSV file.

Simulation parameters

--theta_bg_intensity: Bounds of the uniform distribution to draw background intensity.

--theta_n_akr: Expected number of akr from the Poisson distribution.

--theta_akr_intensity: (Before absolute value) mean and std of AKR intensity.

--theta_gaussian_intensity: Bounds of the uniform distribution to determine the intensity of Gaussian noise.

--theta_overall_channel_intensity: Bounds of the uniform distribution to determine the overall intensity of channels.

--theta_n_channels: Expected number of channels from the Poisson distribution.

--theta_channel_height: Expected half height of the channel from the exponential distribution.

--theta_channel_intensity: Bounds of the uniform distribution to determine the individual intensity of channels.

--disable_dataset_scaling: Disables scaling of synthetic AKR in the dataset.

--dataset_intensity_scale: Mean and standard deviation to scale the images to.

Model parameters

--img_size: Input size to DAARE.

--n_cdae: The number of stacked convolutional denoising autoencoders in DAARE.

--depth: Depth of each convolutional denoising autoencoder.

--n_hidden: Size of each hidden conv2d layer.

--kernel: Kernel shape for the convolutional layers.

--n_norm: The first n convolutional autoencoders to apply layernorm to.

Optimization

--device_ids: Device ids of the GPUs, if GPUs are available.

--n_train: The number of training samples that are included in the training set.

--n_valid: The number of validation samples that are included in the validation set.

--batch_size: Batch size of to use in training and validation.

--n_epochs_per_cdae: The number of epochs to train each convolutional denoising autoencoder.

--learning_rate: The learning rate of each convolutional denoising autoencoder.

API Tutorial

The API was developed to load and run a pretrained model without needing to have a prior understanding of PyTorch. It is also meant to enable easy reading of radio data written to disk and spectrogram generation.

API initialization

from lib.api import DAARE_API

PATH_TO_PRETRAINED = 'daare_pretrained.pt'
api = DAARE_API(PATH_TO_PRETRAINED)

Reading digital_rf files

import numpy as np

# List of file paths
files = ['<path_to_file1>', '<path_to_file2>']
channels = ['ant0', 'ant0']

# Spectrogram parameters
nfft = 1024
bins = 1536
verbose = True

# Read files
obs, freqs, times, starts = api.read_drf(files, channels, 
                                         nfft, bins, verbose=verbose)

Batch denoising with a numpy array

# Larger batch sizes will enable faster
# denoising, though the maximum batch size
# is constrained by the memory available
# on your machine.
batch_size = 16

# DAARE works with 256 x 384 pixel images
# and will resize the spectrogram to fit these
# dimensions. Enabling this flag will
# make the API rescale to the input image
# dimensions; otherwise, it will default to
# return the 256 x 384 pixel output.
retain_size = True

# batch_size, return_same_size, and verbose arguments are optional
obs_denoised = api.denoise(obs, batch_size, retain_size)

Visualize spectrogram

from lib.plot import spects

# Indices of spectrograms to visualize
samples = [0]
# Dimensions of the output figure
nrows_ncols = (len(samples), 2)
# Column that changes the extent of the colorbar
cbar_col = 0
# Plot spectrograms
spects([obs[samples], obs_denoised[samples]], nrows_ncols, cbar_col)

Citation

@article{chang2022removing,
  title={Removing Radio Frequency Interference from Auroral Kilometric Radiation with Stacked Autoencoders},
  author={Chang, Allen and Knapp, Mary and LaBelle, James and Swoboda, John and Volz, Ryan and Erickson, Philip J},
  journal={arXiv preprint arXiv:2210.12931},
  year={2022}
}