Superresolution limit of the ESPRIT algorithm
Abstract
The problem of imaging point objects can be formulated as estimation of an unknown atomic measure from its $M+1$ consecutive noisy Fourier coefficients. The standard resolution of this inverse problem is $1/M$ and superresolution refers to the capability of resolving atoms at a higher resolution. When any two atoms are less than $1/M$ apart, this recovery problem is highly challenging and many existing algorithms either cannot deal with this situation or require restrictive assumptions on the sign of the measure. ESPRIT is an efficient method that does not depend on the sign of the measure. This paper provides an explicit error bound on the support matching distance of ESPRIT in terms of the minimum singular value of Vandermonde matrices. When the support consists of multiple wellseparated clumps and noise is sufficiently small, the support error by ESPRIT scales like ${\rm SRF}^{2\lambda+2} \times {\rm Noise}$, where the SuperResolution Factor (${\rm SRF}$) governs the difficulty of the problem and $\lambda$ is the cardinality of the largest clump. {If the support contains one clump of closely spaced atoms, the minmax error is ${\rm SRF}^{2\lambda +2} \times {\rm Noise}/M$. Our error bound matches the minmax rate up to a factor of $M$ in the small noise regime. Our results therefore establishes the nearoptimality of ESPRIT,} and our theory is validated by numerical experiments.
 Publication:

arXiv eprints
 Pub Date:
 May 2019
 arXiv:
 arXiv:1905.03782
 Bibcode:
 2019arXiv190503782L
 Keywords:

 Computer Science  Information Theory
 EPrint:
 30 pages