Scale sensitive deconvolution of interferometric images

I. Adaptive Scale Pixel (Asp) decomposition

National Radio Astronomy Observatory (Associated Universities Inc. operates the National Radio Astronomy Observatory under cooperative agreement with the National Science Foundation.) , 1003 Lopezville Road, Socorro, NM-87801, USA e-mail: [sbhatnag;tcornwel]@aoc.nrao.edu

Received: 27 February 2004
Accepted: 6 July 2004

Abstract

Deconvolution of the telescope Point Spread Function (PSF) is necessary for even moderate dynamic range imaging with interferometric telescopes. The process of deconvolution can be treated as a search for a model image such that the residual image is consistent with the noise model. For any search algorithm, a parameterized function representing the model such that it fundamentally separates signal from noise will give optimal results. In this paper, the first in a series of forthcoming papers, we argue that in general, spatial correlation length (a measure of the scale of emission) is a stronger separator of the signal from the noise, compared to the strength of the signal alone. Consequently scale sensitive deconvolution algorithms result into more noise-like residuals. We present a scale-sensitive deconvolution algorithm for radio interferometric images, which models the image as a collection of Adaptive Scale Pixels (Asp). Some attempts at optimizing the runtime performance are also presented.