argosim.imaging_utils module#
Imaging utils.
This module contains functions to perform radio interferometric imaging.
- Authors:
Ezequiel Centofanti <ezequiel.centofanti@cea.fr> Samuel Gullin <gullin@ia.forth.gr>
- argosim.imaging_utils.add_noise_uv(vis, uv_mask, sigma=0.1, seed=None)[source]#
Add noise in uv-plane.
Function to add white gaussian noise to the visibilities in the uv-plane.
- Parameters:
vis (np.ndarray) – The visibilities.
mask (np.ndarray) – The uv sampling mask.
sigma (float) – The standard deviation of the noise.
seed (int) – Optional seed to set.
- Returns:
vis – The visibilities with added noise.
- Return type:
np.ndarray
- argosim.imaging_utils.compute_visibilities_grid(sky_uv, uv_mask)[source]#
Compute visibilities gridded.
Function to compute the visibilities from the fourier sky and the uv sampling mask.
- Parameters:
sky_uv (np.ndarray) – The sky model in Fourier/uv domain.
uv_mask (np.ndarray) – The uv sampling mask.
- Returns:
visibilities – Gridded visibilities on the uv-plane.
- Return type:
np.ndarray
- argosim.imaging_utils.grid_uv_samples(uv_samples, sky_uv_shape, fov_size, mask_type='binary', weights=None)[source]#
Grid uv samples.
Compute the uv sampling mask from the uv samples.
- Parameters:
uv_samples (np.ndarray) – The uv samples coordinates in meters.
sky_uv_shape (tuple) – The shape of the sky model in pixels.
fov_size (tuple) – The field of view size in degrees.
mask_type (str) – The type of mask to use. Choose between ‘binary’, ‘histogram’ and ‘weighted’.
weights (np.ndarray) – The weights to use for the mask type ‘weighted’.
- Returns:
uv_mask (np.ndarray) – The uv sampling mask.
uv_samples_indices (np.ndarray) – The indices of the uv samples in pixel coordinates.
- argosim.imaging_utils.simulate_dirty_observation(sky, track, fov_size, multi_band=False, freqs=None, beam=None, sigma=0.2, seed=None)[source]#
Simulate dirty observation.
Function to simulate a radio observation of the sky model from the track uv-samples.
- Parameters:
sky (np.ndarray) – The sky model image.
track (np.ndarray) – The uv sampling points.
fov_size (float) – The field of view size in degrees.
multi_band (bool) – If True, simulate a multi-band observation.
freqs (list) – The frequency list for the multi-band simulation.
beam (Beam) – The beam object to apply to the sky, only used in multi-band simulations.
sigma (float) – The standard deviation of the noise.
seed (int) – Optional seed to set for reproducibility in noise realisation.
- Returns:
obs (np.ndarray) – The dirty observation(s).
dirty_beam (np.ndarray) – The dirty beam(s).