Fundamental limitation of resolution enhancement by wave-field extrapolation

Discrete bandlimited wave-field extrapolation is a resolution enhancement technique equivalent to extending the aperture by analytic continuation of the wave field. This converts the knowledge of the frequency passband of the wave field and the measurement constraints into the form of aperture expansion. This article describes the formulation and structure of the extrapolation algorithm in terms of orthogonal decomposition and recombination. It is also pointed out that the resolution enhancement by wave-field extrapolation is, in general, signal dependent, and the enhancement capability is governed by the effective subspace associated with the singular-value distribution.