Perform empirical mode decomposition

• Purpose
  This tool can be used to perform empirical mode decomposition, also perform the spectrum analysis, including frequency transform and Hilbert-Huang transform.

• Installation
  Download the file Empirical Mode Decomposition.opx, and then drag-and-drop onto the Origin workspace. An icon will appear in the Apps gallery window.
• Operation
  With the signal column in worksheet selected, click the app icon from the Apps gallery window. Then a dialog will pop up, then change the settings in dialog accordingly, then click OK button.
• Dialog Setings
  • Input tab
    • Input: Specify the input signal. You can select from the context menu, or open the Column Browser from the context menu, and then select signal column.
  • Sifting tab
    • Threshold: Specify the threshold at which the overall sifting process will stop.
    • Maximum IMFs: Specify how many IMFs (Intrinsic Mode Functions) to compute. The maximum number of IMFs to compute. If Auto (-1), it will compute IMFs until the stop condiction is met.
    • Show IMF Options: Check to show the options for computing the next IMF from a dataset.
    • Show Envelope Options: Check to show the options for interpolating the amplitude envelope of a signal.
    • Show Extrema Options: Check to show the options for identifying and pading the extrema in a signal.
    • IMF Options group:
      • Scale Factor: The average of the upper and lower envelope is multiplied by this value before being subtracted from the data. This value should be between 0 and 1 (exclude 0 but include 1).
      • Maximum Iterations: Maximum number of iterations to compute.
      • Energy Diff. Threshold (in Decibels): Threshold for energy difference (in decibels) between IMF and residual to stop overall sift.
      • Stop Method: How to stop sifting. Options include Standard Deviation Threshold, Rilling Metric and Fixed Number.
      • St. Dev. Threshold: When Stop Method is Standard Deviation Threshold, this value is the threshold at which the sift of each IMF will be stopped.
      • Rilling Metric: When Stop Method is Rilling Metric, an evaluation function (E) is defined by dividing the residual by the mode amplitude. The sift continues until E < sd1 for the fraction (1-alpha) of the data, and E < sd2 for the remainder. This parameter is for specifying sd1, sd2, and alpha sequentially, separated by space.
    • Envelope Options group:
      • Interpolation Method: Specify interpolation method used for interpolating the amplitude envelope of a signal. Options include B-Spline and PCHIP 1-D Monotonic Cubic.
    • Extrema Options group:
      • Pad Width: Number of additional extrema to add to the start and end.
      • Parabolic Extrema: check to refine the extrema positions by parabolic interpolation.
      • Pad Extrema Magnitude Options group
        • Statistic Length: How many data to use for calculating the statistic for padding extrema magnitudes.
  • Spectrum Analysis tab
    • Frequency Transform: Check to perform frequency transform.
    • Frequency Transform Options group
      • Sample Rate (Hz): Specify sampling rate. If Auto, it will compute from the X of the signal.
      • Method: The method for computing the frequency stats. Options include Hilbert Transform, Quadrature Transform, Direct Quadrature Transform, and Amplitude Normallized Hilbert Transform,
      • Window Length for Smooth Phase: Specify length of window when smoothing the unwrapped phase.
    • Hilbert-Huang Transform: Check to perform Hilbert-Huang Transform. Also, frequency transform is performed together.
    • Hilbert-Huang Transform Options group
      • With Time Dimension (2D): Check to consider the time dimension, that is, if checked, the Hilbert-Huang transform instataneous frequency and instantaneous amplitude time-series and represents the energy of a signal across time and frequency, if not checked, only across frequency.
      • Instantaneous Amplitude Weighted: If checked, instantaneous amplitude is used as weight, otherwise, no weight is used.
      • Frequency Start From: The start value of frequency range.
      • Frequency End At: The end value of frequency range.
      • Number of Frequencies: How many frequencies is used for the frequency range.
      • Frequency Type: Specify to use Linear or Ln spacing for frequency.
      • Mode: Specify the mode of sum, Energy or Amplitude.
  • Output tab
    • Output: Specify where to output the results. New Sheet will create new sheet in the same workbook of the source signal for the results, and New Book will create a new workbook for the results.
  • OK and Cancel Buttons: Click OK button to output the results and close dialog, and click Cancel button to close the dialog only.
• Note: The algorithm used in this app is from this page, for more details about algorithm, please refer to that page.

v1.2 2023/9/18 Add hint for restarting Origin after Python package installation
v1.1 2022/3/4 Fix emd package version issue