On the extraction of instantaneous frequencies from ridges in time-frequency representations of signals
For signal processing researchers, this work provides a more robust and user-friendly tool for oscillatory component extraction, though it is an incremental improvement over existing ridge extraction techniques.
The paper addresses the challenge of extracting instantaneous frequencies from ridges in time-frequency representations, proposing a highly adaptive method based on dynamic path optimization and fixed point iteration that requires no parameter adjustment. The method demonstrates superior accuracy and speed on simulated and real data.
The extraction of oscillatory components and their properties from different time-frequency representations, such as windowed Fourier transform and wavelet transform, is an important topic in signal processing. The first step in this procedure is to find an appropriate ridge curve: a sequence of amplitude peak positions (ridge points), corresponding to the component of interest. This is not a trivial issue, and the optimal method for extraction is still not settled or agreed. We discuss and develop procedures that can be used for this task and compare their performance on both simulated and real data. In particular, we propose a method which, in contrast to many other approaches, is highly adaptive so that it does not need any parameter adjustment for the signal to be analysed. Being based on dynamic path optimization and fixed point iteration, the method is very fast, and its superior accuracy is also demonstrated. In addition, we investigate the advantages and drawbacks that synchrosqueezing offers in relation to curve extraction. The codes used in this work are freely available for download.