15 research outputs found
Super-Resolution from Short-Time Fourier Transform Measurements
While spike trains are obviously not band-limited, the theory of
super-resolution tells us that perfect recovery of unknown spike locations and
weights from low-pass Fourier transform measurements is possible provided that
the minimum spacing, , between spikes is not too small. Specifically,
for a cutoff frequency of , Donoho [2] shows that exact recovery is
possible if , but does not specify a corresponding recovery
method. On the other hand, Cand\`es and Fernandez-Granda [3] provide a recovery
method based on convex optimization, which provably succeeds as long as . In practical applications one often has access to windowed Fourier
transform measurements, i.e., short-time Fourier transform (STFT) measurements,
only. In this paper, we develop a theory of super-resolution from STFT
measurements, and we propose a method that provably succeeds in recovering
spike trains from STFT measurements provided that .Comment: IEEE International Conference on Acoustics, Speech, and Signal
Processing (ICASSP), May 2014, to appea
Sampling and Super-resolution of Sparse Signals Beyond the Fourier Domain
Recovering a sparse signal from its low-pass projections in the Fourier
domain is a problem of broad interest in science and engineering and is
commonly referred to as super-resolution. In many cases, however, Fourier
domain may not be the natural choice. For example, in holography, low-pass
projections of sparse signals are obtained in the Fresnel domain. Similarly,
time-varying system identification relies on low-pass projections on the space
of linear frequency modulated signals. In this paper, we study the recovery of
sparse signals from low-pass projections in the Special Affine Fourier
Transform domain (SAFT). The SAFT parametrically generalizes a number of well
known unitary transformations that are used in signal processing and optics. In
analogy to the Shannon's sampling framework, we specify sampling theorems for
recovery of sparse signals considering three specific cases: (1) sampling with
arbitrary, bandlimited kernels, (2) sampling with smooth, time-limited kernels
and, (3) recovery from Gabor transform measurements linked with the SAFT
domain. Our work offers a unifying perspective on the sparse sampling problem
which is compatible with the Fourier, Fresnel and Fractional Fourier domain
based results. In deriving our results, we introduce the SAFT series (analogous
to the Fourier series) and the short time SAFT, and study convolution theorems
that establish a convolution--multiplication property in the SAFT domain.Comment: 42 pages, 3 figures, manuscript under revie