A New Concept for Compressive Radio-interferometric Imaging: the Modulated Rank-one Projection Model

The emerging generation of radio-interferometric (RI) arrays will form images with unprecedented sensitivity and resolution, generating visibility data volumes scaling as O(Q²B) for Q antennas and B snapshots. Under the assumption that the radio emission exhibits a flat spectrum, we extend the modulated rank-one projection (MROP) model to monochromatic image formation from wideband observations with K frequency channels. The multi-frequency extension of the MROP model introduces additional random modulations across frequency channels. The extended MROP is validated in both simulation and from real data, with comparison to the classical and baseline-dependent averaging (BDA) models, using the uSARA optimisation algorithm for image formation. Our results are in agreement with our earlier results using single-channel observation that the data size necessary to preserve imaging quality using MROPs is reduced to the order of image size, well below the original and BDA data sizes.