论文标题
紧凑型的准紧密多帧数具有高平衡订单和紧凑的框架变换
Compactly Supported Quasi-tight Multiframelets with High Balancing Orders and Compact Framelet Transforms
论文作者
论文摘要
在理论和应用中,Framelets(又名小波框架)都很感兴趣。经常,通过流行的倾斜延伸原理(OEP)来建造具有高消失时刻的紧密或双重印象。尽管OEP可以增加消失的力矩以提高稀疏性,但它对于标量框架存在严重的缺点:相关的离散帧转换通常不紧凑,而反卷积是不可避免的。在这里,我们说,如果只能使用有限支持的过滤器来卷积实现帧变换,那么它是紧凑的。另一方面,与经过广泛研究的标量前框形成鲜明对比的是,通过OEP从可改进的矢量函数中得出的多帧(又称矢量框架)的研究较少,并且远远远没有理解。同样,大多数构建的多帧通常都缺乏降低稀疏性的平衡属性。在本文中,我们对准连续的多帧特别感兴趣,这些帧是特殊的双重帧速度,但几乎相同地作为紧密的多帧。从任何至少有两个条目的紧凑型\ emph {可再固定的矢量函数}中,我们证明我们始终可以通过OEP构造一个紧凑的准tight tight多帧,以至于(1)其关联的离散framelet变换是紧凑的,并且具有最高的平衡顺序; (2)所有紧凑的帧发电机的消失矩可能最高的顺序,与其基本可改进的矢量函数的近似/精度顺序相匹配。该结果证明了OEP比标量框架上的多帧(保留所有所需属性)的优势。
Framelets (a.k.a. wavelet frames) are of interest in both theory and applications. Quite often, tight or dual framelets with high vanishing moments are constructed through the popular oblique extension principle (OEP). Though OEP can increase vanishing moments for improved sparsity, it has a serious shortcoming for scalar framelets: the associated discrete framelet transform is often not compact and deconvolution is unavoidable. Here we say that a framelet transform is compact if it can be implemented by convolution using only finitely supported filters. On the other hand, in sharp contrast to the extensively studied scalar framelets, multiframelets (a.k.a. vector framelets) derived through OEP from refinable vector functions are much less studied and are far from well understood. Also, most constructed multiframelets often lack balancing property which reduces sparsity. In this paper, we are particularly interested in quasi-tight multiframelets, which are special dual multiframelets but behave almost identically as tight multiframelets. From any compactly supported \emph{refinable vector function having at least two entries}, we prove that we can always construct through OEP a compactly supported quasi-tight multiframelet such that (1) its associated discrete framelet transform is compact and has the highest possible balancing order; (2) all compactly supported framelet generators have the highest possible order of vanishing moments, matching the approximation/accuracy order of its underlying refinable vector function. This result demonstrates great advantages of OEP for multiframelets (retaining all the desired properties) over scalar framelets.