2013A&A...559A..73F


Query : 2013A&A...559A..73F

2013A&A...559A..73F - Astronomy and Astrophysics, volume 559A, 73-73 (2013/11-1)

Optimal arrays for compressed sensing in snapshot-mode radio interferometry.

FANNJIANG C.

Abstract (from CDS):

Radio interferometry has always faced the problem of incomplete sampling of the Fourier plane. A possible remedy can be found in the promising new theory of compressed sensing (CS), which allows for the accurate recovery of sparse signals from sub-Nyquist sampling given certain measurement conditions. We provide an introductory assessment of optimal arrays for CS in snapshot-mode radio interferometry, using orthogonal matching pursuit (OMP), a widely used CS recovery algorithm similar in some respects to CLEAN. We focus on comparing centrally condensed (specifically, Gaussian) arrays to uniform arrays, and randomized arrays to deterministic arrays such as the VLA. The theory of CS is grounded in a) sparse representation of signals and b) measurement matrices of low coherence. We calculate the mutual coherence of measurement matrices as a theoretical indicator of arrays' suitability for OMP, based on the recovery error bounds in Donoho et al. (2006, IEEE Trans. Inform. Theory, 52, 1289). OMP reconstructions of both point and extended objects are also run from simulated incomplete data. Optimal arrays are considered for objects represented in 1) the natural pixel basis and 2) the block discrete cosine transform (BDCT). We find that reconstructions of the pixel representation perform best with the uniform random array, while reconstructions of the BDCT representation perform best with normal random arrays. Slight randomization to the VLA also improves it dramatically for CS recovery with the pixel basis. In the pixel basis, array design for CS reflects known principles of array design for small numbers of antennas, namely of randomness and uniform distribution. Differing results with the BDCT, however, emphasize the need to study how sparsifying bases affect array design before CS can be optimized for radio interferometry.

Abstract Copyright:

Journal keyword(s): instrumentation: interferometers - methods: numerical - techniques: image processing - radio continuum: general

Simbad objects: 8

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Number of rows : 8
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 NGC 383 rG 01 07 24.9647814840 +32 24 45.132586200   13.6 12.14     ~ 756 3
2 M 33 GiG 01 33 50.8965749232 +30 39 36.630403128 6.17 6.27 5.72     ~ 5603 1
3 SNR G130.7+03.1 SNR 02 05 37.0 +64 49 42           ~ 595 4
4 3C 75 PaG 02 57 41.64 +06 01 28.0           ~ 297 1
5 M 1 SNR 05 34 32 +22 00.8           ~ 6002 1
6 NGC 2403 AGN 07 36 51.3381434280 +65 36 09.650825640 9.31 8.84 8.38 8.19   ~ 1721 1
7 M 87 AGN 12 30 49.42338414 +12 23 28.0436859 10.16 9.59 8.63   7.49 ~ 6826 3
8 NAME Cas A SNR 23 23 24.000 +58 48 54.00     14.30     ~ 2668 1

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2023.01.30-22:05:32

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