IEEE TRANSACTIONS ON INFORMATION THEORY, VOL. 52, NO. 4, APRIL 2006 1289 Compressed detecting David L. Donoho, Member, IEEE robSuppose is an unknown vector in (a digital contrive or signal); we plan to measure general linear functionals of and then(prenominal) reconstruct. If is known to be compressible by transform jurisprudence with a known transform, and we reconstruct via the nonlinear procedure de?ned here, the sink of measurements can be dramatically smaller than the size . Thus, incontestable natural classes of images with picture elements need only = ( 1 4 log5 2 ( )) nonadaptive nonpixel samples for faithful recovery, as opposed to the usual pixel samples. More speci?cally, suppose has a sparse representation in some orthonormal basis (e.g., wavelet, Fourier) or tight frame (e.g., curvelet, Gabor)so the coef?cients belong to an ball for 0 1. The closely cardinal coef?cients in that expansion allow reconstructive memory with 2 error ( 1 2 1 ). It is poss ible to design = ( log( )) nonadaptive measurements allowing reconstruction with accuracy comparable to that attainable with direct intimacy of the most important coef?cients. Moreover, a good approximation to those important coef?cients is extracted from the measurements by solving a linear program primer coat hobbyhorse in signal processing.
The nonadaptive measurements have the suit of ergodic linear combinations of basis/frame elements. Our results use the notions of optimum recovery, of -widths, and information-based complexity. We depend the jellyfand -widths of balls in high-dimensional Euclidean space in the ted dy 0 1, and give a criterion identifying nea! r-optimal subspaces for Gelfand -widths. We extract that most subspaces are near-optimal, and show that convex optimization (Basis Pursuit) is a near-optimal way to extract information derived from these near-optimal subspaces. Index scathe adaptative sampling, almost-spherical sections of Banach spaces, Basis Pursuit, eigenvalues of random matrices, Gelfand -widths, information-based...If you want to enamor a full essay, order it on our website: OrderCustomPaper.com
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