For non-stationary signal in ultrasonic inspection, an effective denoising method based on Hilbert-Huang transform (HHT) is presented and a few key questions using the HHT method are discussed. The overall scheme of HHT includes two parts which are empirical mode decomposition (EMD) algorithm and a sum of intrinsic mode functions (IMF). Through the EMD process, individual IMF can be found. The ...

The Hilbert-Huang transform (HHT) is a powerful method for nonlinear and non-stationary vibrations analysis. This approach consists of two basic parts of empirical mode decomposition (EMD) and Hilbert spectral analysis (HSA). To achieve the reliable results, Bedrosian and Nuttall theorems should be satisfied. Otherwise, the phase and amplitude functions are mixed together and consequently, the ...

In order to distinguish the difference of non-stationary signals, the novel time-frequency analysis approach, i.e. Hilbert-Huang transform (HHT), is applied in this paper. Firstly, Hilbert-Huang transform is briefly introduced. Secondly, two different non-stationary signals are described in Empirical Mode Decomposition (EMD) and Hilbert spectra. With these results, the two signals that looked a...

‎There are different feature extraction methods in brain-computer interfaces (BCI) based on Steady-State Visually Evoked Potentials (SSVEP) systems‎. ‎This paper presents a comparison of five methods for stimulation frequency detection in SSVEP-based BCI systems‎. ‎The techniques are based on Power Spectrum Density Analysis (PSDA)‎, ‎Fast Fourier Transform (FFT)‎, ‎Hilbert‎- ‎Huang Transform (H...

Hilbert Huang Transform (HHT) is an empirical timefrequency analysis method firstly proposed by N. E. Huang in 1998. This method is suitable for nonlinear and non-stationary signal processing and thus employed for bioelectrical signal processing and analysis in recent years. However, the large computation cost of HHT restricts its applications for real-time signal processing. This paper present...

Time-frequency distribution has received a growing utilization for analysis and interpretation of nonlinear and nonstationary processes in a variety of fields. Among them, two methods, such as, the empirical mode decomposition EMD with Hilbert transform HT which is termed as the Hilbert-Huang Transform HHT and the Hilbert spectrum based on maximal overlap discrete wavelet package transform MODW...

The record of human brain neural activities, namely electroencephalogram (EEG), is generally known as a non-stationary and nonlinear signal. In many applications, it is useful to divide the EEGs into segments within which the signals can be considered stationary. Combination of empirical mode decomposition (EMD) and Hilbert transform, called Hilbert-Huang transform (HHT), is a new and powerful ...

Hilbert-Huang Transform (HHT) and its improved method are introduced to detect and analyze power quality in ship power system for the first time, in this paper. The HHT method is used to detect surge current, voltage sag and swell, voltage interruption, etc. of the ship power system. By means of Hilbert-Huang transform, Beginning time, ending time, time-frequency, timeamplitude of the disturban...

the record of human brain neural activities, namely electroencephalogram (eeg), is generally known as a non-stationary and nonlinear signal. in many applications, it is useful to divide the eegs into segments within which the signals can be considered stationary. combination of empirical mode decomposition (emd) and hilbert transform, called hilbert-huang transform (hht), is a new and powerful ...

The effective noise reduction schemes in ultrasonic inspection have shown significant role for detection of flaws in materials. This paper presents the comparative result of noise reducing schemes based on Hilbert-Huang transform and Wavelet transform. The basic principle of HHT scheme includes two parts which are empirical mode decomposition (EMD) algorithm and a sum of intrinsic mode function...