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arXiv cs/0703045cs.ITmath.IT
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使用冗余帧的稀疏表示的性能界限

Performance Bounds on Sparse Representations Using Redundant Frames

Mehmet Akçakaya, Vahid Tarokh

摘要:

我们认为近似的信号的一个帧的元素在一个复杂的向量空间的维度$N$和制定无噪声和噪声稀疏表示问题。无噪声表示问题是找到信号$\mathbf{r}$的稀疏表示,假定这样的表示存在。在这种情况下,我们显式地构造一个框架,称为范德蒙框架,对于该框架,可以使用$O(N^2)$操作唯一地解决无噪声稀疏表示问题,只要$\mathbf{r}$的稀疏表示中的非零系数的数量对于某些$0 \le ε\le 0.5$是$εN$,从而改进Candes和Tao \cite{Candes-Tao}的结果。我们还表明,$ε\le 0.5$不能放松不违反唯一性。噪声稀疏表示问题是找到满足失真准则的信号$\mathbf{r}$的稀疏表示。在这种情况下,我们建立一个下界之间的权衡稀疏的表示,潜在的失真和冗余的任何给定的帧。

英文摘要:

We consider approximations of signals by the elements of a frame in a complex vector space of dimension $N$ and formulate both the noiseless and the noisy sparse representation problems. The noiseless representation problem is to find sparse representations of a signal $\mathbf{r}$ given that such representations exist. In this case, we explicitly construct a frame, referred to as the Vandermonde frame, for which the noiseless sparse representation problem can be solved uniquely using $O(N^2)$ operations, as long as the number of non-zero coefficients in the sparse representation of $\mathbf{r}$ is $εN$ for some $0 \le ε\le 0.5$, thus improving on a result of Candes and Tao \cite{Candes-Tao}. We also show that $ε\le 0.5$ cannot be relaxed without violating uniqueness. The noisy sparse representation problem is to find sparse representations of a signal $\mathbf{r}$ satisfying a distortion criterion. In this case, we establish a lower bound on the trade-off between the sparsity of the representation, the underlying distortion and the redundancy of any given frame.

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