AN ADAPTIVE OPTIMAL-KERNEL TIME-FREQUENCY REPRESENTATION
AN ADAPTIVE OPTIMAL-KERNEL TIME-FREQUENCY REPRESENTATION
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DOI：
10.1109/78.469854
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发表时间：
1995-10-01
影响因子：
5.4
通讯作者：
BARANIUK, RG
中科院分区：
文献类型：
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作者：
JONES, DL;BARANIUK, RG
具有固定窗口或核的时频表示在许多应用中占据突出地位，但仅对有限类别的信号表现良好。具有信号相关核的表示可以克服这一限制。然而，尽管它们通常表现良好，但大多数现有方案是面向块的技术，不适合在线实现或跟踪具有随时间变化的特性的信号分量。这里开发的时频表示，基于随时间适应的信号相关的径向高斯核，克服了这些困难。该方法采用短时模糊函数用于核优化和作为计算表示的恒定时间片的中间步骤，仔细的算法设计提供了合理有效的计算，并允许在线实现，某些增强，如甘蔗核约束和近似保留的边缘，很容易合并很少的额外计算。虽然比固定内核表示稍微昂贵，但这种新技术通常提供更好的性能，几个例子说明了它在合成和真实世界信号上的行为。
Time-frequency representations with fixed windows or kernels figure prominently in many applications, but perform well only for limited classes of signals, Representations with signal-dependent kernels can overcome this limitation, However, while they often perform well, most existing schemes are block-oriented techniques unsuitable for on-line implementation or for tracking signal components with characteristics that change with time, The time-frequency representation developed here, based on a signal-dependent radially Gaussian kernel that adapts over time, surmounts these difficulties, The method employs a short-time ambiguity function both for kernel optimization and as an intermediate step in computing constant-time slices of the representation, Careful algorithm design provides reasonably efficient computation and allows on-line implementation, Certain enhancements, such as cane-kernel constraints and approximate retention of marginals, are easily incorporated with little additional computation. While somewhat more expensive than fixed-kernel representations, this new technique often provides much better performance, Several examples illustrate its behavior on synthetic and real-world signals.