基于条件对抗生成时频分布的多分量信号瞬时频率估计

Instantaneous Frequency Estimation for Multicomponent Signals Based on Conditional Adversarial Generation of Time-Frequency Distribution

  • 摘要: 瞬时频率(Instantaneous Frequency,IF)估计在多分量信号处理中具有重要意义,而现有方法在信号分量的IF曲线相近或相交时估计准确度不佳。针对这一问题,本文提出一种基于条件对抗生成时频分布的多分量信号IF估计方法。该方法首先采用时频分析产生信号的时频图像(例如掩膜维格纳分布)作为条件生成对抗网络(Conditional Generative Adversarial Networks, CGAN)的原始数据集,通过训练CGAN进行学习之后生成接近理想时频分布的时频图像。根据这些图像,本文利用一种改进的维特比算法提取出不同分量的IF曲线。其改进点在于增加了一个线段梯度的惩罚项,使维特比算法在分量相交的时频区域仍有准确的IF估计。实验结果表明,该方法能够有效且准确地估计分量相近或相交情况下信号的IF信息。

     

    Abstract: Instantaneous frequency (IF) estimation plays an important role in multicomponent signal processing. However, most existing methods achieve poor performance when IF curves of signal components are closely spaced or intersecting. To address the above problem, this paper proposes a multicomponent signal IF estimation method which tries to approach ideal time-frequency (TF) distribution by exploiting conditional adversarial generation. Firstly, this method adopts TF distribution (TFD) images (e.g., masked Wigner-Ville distribution in this paper) via TF analysis as the original dataset of conditional generative adversarial network (CGAN). Based on the produced dataset, the CGAN is trained to learn features of input images and then we use the trained network to generate new TFD images, which are closer to ideal TFDs. According to these optimized TFD images, an improved Viterbi algorithm is employed to extract IF curves of different components. This improved algorithm introduces a penalty function corresponding to line segment gradient in order to guarantee the estimation accuracy when signal components are intersecting in TF domain. Experimental results show the effectiveness and superiority of the proposed method in the case where these IF curves are closely spaced or intersecting.

     

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