BRISK: An accelerated wide-field imager for radio astronomy
Abstract
Wide-field interferometric imaging with non-coplanar arrays is computationally expensive, particularly as we move towards imaging large datasets from next-generation telescopes such as the Square Kilometre Array (SKA). The dominant imaging cost arises during the gridding and degridding steps, where large w-terms require correction. In w-projection, this correction uses w-dependent convolution kernels whose support grows rapidly with field of view (FoV) and maximum |w|. In w-stacking, visibilities are partitioned into discrete w-layers, each requiring a 2D Fourier transform and image-domain phase correction; the required number of layers increases with |w|max and FoV. We present BRISK (Baseline-aware Rank-compressed Interferometric Sky-imaging Toolkit), a wide-field interferometric imaging algorithm that accelerates w-projection by exploiting the low-rank structure of its convolution kernels. For each w-plane, the full 2D gridding kernel is compressed using a truncated randomised singular value decomposition (SVD), yielding a compact representation from which the SVD-compressed kernel can be reconstructed on the fly while preserving the dominant kernel energy. We benchmark memory usage, runtime, and accuracy against CASA's w-projection and WSClean's w-stacking, w-gridding and image-domain gridding algorithms on a simulated 15 × 15 grid of point sources, as well as the SKA1-Low GLEAM simulated measurement sets. BRISK runs up to 2443 times faster than CASA, and up to 132 times faster than WSClean, while maintaining a peak-flux bias of less than 1% at the largest image sizes and comparable peak memory usage.
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BibTeX
@misc{ogden2026brisk,
title = {{BRISK: An accelerated wide-field imager for radio astronomy}},
author = {Oliver Ogden and Wesley Armour},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.23671},
eprint = {2610.23671},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.23671},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - BRISK: An accelerated wide-field imager for radio astronomy
AU - Oliver Ogden
AU - Wesley Armour
PY - 2026
DA - 2026/10/16
PB - arXiv
DO - 10.48550/arxiv.2610.23671
UR - https://arxiv.org/abs/2610.23671
AB - Wide-field interferometric imaging with non-coplanar arrays is computationally expensive, particularly as we move towards imaging large datasets from next-generation telescopes such as the Square Kilometre Array (SKA). The dominant imaging cost arises during the gridding and degridding steps, where large w-terms require correction. In w-projection, this correction uses w-dependent convolution kernels whose support grows rapidly with field of view (FoV) and maximum |w|. In w-stacking, visibilities are partitioned into discrete w-layers, each requiring a 2D Fourier transform and image-domain phase correction; the required number of layers increases with |w|_max and FoV. We present BRISK (Baseline-aware Rank-compressed Interferometric Sky-imaging Toolkit), a wide-field interferometric imaging algorithm that accelerates w-projection by exploiting the low-rank structure of its convolution kernels. For each w-plane, the full 2D gridding kernel is compressed using a truncated randomised singular value decomposition (SVD), yielding a compact representation from which the SVD-compressed kernel can be reconstructed on the fly while preserving the dominant kernel energy. We benchmark memory usage, runtime, and accuracy against CASA's w-projection and WSClean's w-stacking, w-gridding and image-domain gridding algorithms on a simulated 15 × 15 grid of point sources, as well as the SKA1-Low GLEAM simulated measurement sets. BRISK runs up to 2443 times faster than CASA, and up to 132 times faster than WSClean, while maintaining a peak-flux bias of less than 1% at the largest image sizes and comparable peak memory usage.
ER -