arXiv:2501.15764eess.AScs.SD2025-01被引 1

新方法通过优化小波构型实现高精度无交叉项时频分析。

RIFT: Entropy-Optimised Fractional Wavelet Constellations for Ideal Time-Frequency Estimation

  • 构建多局部曲率小波簇,用熵优化融合成稀疏表示。
  • 抑制交叉项并达到与维格纳分布相当的时频分辨率。
  • 适合语音、音乐等非平稳信号的轨迹追踪与可视化。

本文提出一种新的复杂非平稳信号理想时频表示(ITFR)估计方法——重建理想分数变换(RIFT)。RIFT通过连续分数小波变换(CFWT)在不同局部时频曲率下的构型组合,利用局部熵基稀疏度度量将这些构型融合为单一优化的能量表示,有效分辨自项并压制交叉项。最后采用正性约束的卢西-理查森反卷积与总变差正则化,获得接近维格纳-维勒分布(WVD)分辨率的高精度时频表示。论文完整推导了所选CFWT构型对应的科恩类卷积核。优化过程还生成瞬时相位方向(IPD)场,可可视化语音或音乐片段中的局部曲率,并用于卡尔曼跟踪,实现信号分量轨迹提取,进而构建样条-RIFT变体。在合成与真实信号上的评估表明,该算法能有效抑制交叉项,相比现有方法显著提升时频精度,具有广泛的应用潜力。

原文摘要 · Abstract (English)

We introduce a new method for estimating the Ideal Time-Frequency Representation (ITFR) of complex nonstationary signals. The Reconstructive Ideal Fractional Transform (RIFT) computes a constellation of Continuous Fractional Wavelet Transforms (CFWTs) aligned to different local time-frequency curvatures. This constellation is combined into a single optimised time-frequency energy representation via a localised entropy-based sparsity measure, designed to resolve auto-terms and attenuate cross-terms. Finally, a positivity-constrained Lucy-Richardson deconvolution with total-variation regularisation is applied to estimate the ITFR, achieving auto-term resolution comparable to that of the Wigner-Ville Distribution (WVD), yielding the high-resolution RIFT representation. The required Cohen's class convolutional kernels are fully derived in the paper for the chosen CFWT constellations. Additionally, the optimisation yields an Instantaneous Phase Direction (IPD) field, which allows the localised curvature in speech or music extracts to be visualised and utilised within a Kalman tracking scheme, enabling the extraction of signal component trajectories and the construction of the Spline-RIFT variant. Evaluation on synthetic and real-world signals demonstrates the algorithm's ability to effectively suppress cross-terms and achieve superior time-frequency precision relative to competing methods. This advance holds significant potential for a wide range of applications requiring high-resolution cross-term-free time-frequency analysis.

时频分析小波变换信号处理非平稳信号

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