科研之友
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摘要
Compressed sensing is a novel theory for signal sampling, which breaks through Nyquist/Shannon sampling limitation and makes it into reality that one can efficiently collect and robustly reconstruct a sparse signal. However, some signals exhibit additional structures in some redundant dictionaries, which is called block-sparse signal. In this study, non-convex block-sparse compressed sensing with redundant dictionaries is investigated. Under the block D-RIP condition (root 2/2) <= delta(2k vertical bar tau)< 1, a sufficient condition for robust signal reconstruction with redundant dictionaries by mixed l (2)/ l (p)(0 < p < 1) minimisation is established. Furthermore, the authors' theoretical results show that, under the assumption that (root 2/2) <= delta 2(k vertical bar tau) < 1, p is an element of (0, (p) over cap], where @@@ (p) over cap ={1.6835(1 - delta(2k vertical bar tau), delta(2k vertical bar tau) is an element of[root 2/2,0.73) @@@ 0.45418, delta is an element of(0.73, 0.7983) @@@ 2.2522(1 - delta(2k vertical bar tau)) delta(2k vertical bar tau) [0.7883, 1), @@@ then the block k-sparse signal can be stably reconstructed via non- convex l(2)/l(p) minimisation with redundant dictionaries in the presence of noise. Particularly, this improves the existed result when the block- sparse signal degenerate to the conventional signal case. Besides, the authors also obtain robust reconstruction condition and error upper bound estimation when the block number is no more than four times the sparsity of the block signal( <= 4k). Moreover, the numerical experiments to some extent testify the performance of non- convex l (2)/ l (p)( 0 < p < 1) minimisation with redundant dictionaries.
