论文标题

抽样限制功能的流程

Sampling the flow of a bandlimited function

论文作者

Aldroubi, Akram, Gröchenig, Karlheinz, Huang, Longxiu, Jaming, Philippe, Krishtal, Ilya, Romero, José Luis

论文摘要

我们从其状态的时空样本中分析了重建功能$ f $的问题,$ f_t = ϕ_t \ ast f $是由内核$ ϕ_t $卷积产生的。众所周知,在自然现象中,$ f $的统一时空样本不足以以稳定的方式重建$ f $。为了实现稳定的重建,必须使用具有周期性非均匀间隔样品的时空抽样,如LU和Vetterli所示。我们表明,通过条件数量测量,重建的稳定性控制着空间样品之间的最大差距。我们提供了有关此结果的定量陈述。此外,我们表明,以下空间速率的均匀动力学样本代替了不规则的时空样本,使人们可以稳定地重建函数$ \ widehat f $,远离某些,明确描述的盲点。我们还考虑了一些有限的尺寸尺寸子集,即使在盲点内,稳定的重建也可能是可能的。我们使用Remez-Turán类型不等式获得了其定量估计。在途中,我们获得了针对pr酸球波函数的Remez-Turán不等式。为了说明我们的结果,我们为热流问题提供了一些数字和明确的估计。

We analyze the problem of reconstruction of a bandlimited function $f$ from the space-time samples of its states $f_t=ϕ_t\ast f$ resulting from the convolution with a kernel $ϕ_t$. It is well-known that, in natural phenomena, uniform space-time samples of $f$ are not sufficient to reconstruct $f$ in a stable way. To enable stable reconstruction, a space-time sampling with periodic nonuniformly spaced samples must be used as was shown by Lu and Vetterli. We show that the stability of reconstruction, as measured by a condition number, controls the maximal gap between the spacial samples. We provide a quantitative statement of this result. In addition, instead of irregular space-time samples, we show that uniform dynamical samples at sub-Nyquist spatial rate allow one to stably reconstruct the function $\widehat f$ away from certain, explicitly described blind spots. We also consider several classes of finite dimensional subsets of bandlimited functions in which the stable reconstruction is possible, even inside the blind spots. We obtain quantitative estimates for it using Remez-Turán type inequalities. En route, we obtain a Remez-Turán inequality for prolate spheroidal wave functions. To illustrate our results, we present some numerics and explicit estimates for the heat flow problem.

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