The varying w spread spectrum effect for radio interferometric imaging

TL;DR

This paper investigates how the spread spectrum effect, caused by wide field-of-view in radio interferometry, enhances image reconstruction quality by increasing incoherence and sparsity, especially when the chirp modulation varies per measurement.

Contribution

It extends previous studies by analyzing the impact of variable chirp modulation on image quality, showing significant improvements over no modulation.

Findings

Reconstruction quality improves with variable chirp modulation.

Performance approaches that of maximal, constant chirp modulation.

Variable chirp enhances incoherence and sparsity in measurements.

Abstract

We study the impact of the spread spectrum effect in radio interferometry on the quality of image reconstruction. This spread spectrum effect will be induced by the wide field-of-view of forthcoming radio interferometric telescopes. The resulting chirp modulation improves the quality of reconstructed interferometric images by increasing the incoherence of the measurement and sparsity dictionaries. We extend previous studies of this effect to consider the more realistic setting where the chirp modulation varies for each visibility measurement made by the telescope. In these first preliminary results, we show that for this setting the quality of reconstruction improves significantly over the case without chirp modulation and achieves almost the reconstruction quality of the case of maximal, constant chirp modulation.