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timeline - approximation thanks to FFT/iFFT

✓ Published0🌍 Public
KKcnarf
Last edited Dec 3, 2018
Created on Feb 6, 2017

The example demonstrates how a timeline signal can be reconstructed from its frequency components using an inverse Fast Fourier Transform (iFFT), with the approximation quality controlled by a threshold slider. Dragging points on the top timeline updates the signal and its forward FFT representation, while adjusting the threshold in the bottom graph filters which components contribute to the rebuilt series. Built with D3.js v4, the visualization uses SVG for interactive rendering, a custom JavaScript FFT algorithm for spectral analysis, and animated transitions to show the relationship between time-domain and frequency-domain views.

AI-generated description

This block is a continuation of a previous one, and an experimentation of how to rebuilt an approximation of a timeline thanks to an inverse Fast Fourier Transform (iFFT) algorithm.

Usages :

  • in the top graph, Drag & Drop points to update the timeline, or use the shortcuts below the graph; this will update the corresponding FFT components (in the bottom graph)
  • in the bottom graph, move the treshold up and down; this will rebuild another timeline (in the top graph) based on the retained FFT components

Notes:

I've done other bl.ocks dealing with timeline analyses:

  • another <a href='http://bl.ocks.org/Kcnarf/5118ba2eb78edfcf645e'>block</a> highlights how important detrending is when trying to detect seasonality
  • another <a href='http://bl.ocks.org/Kcnarf/8c462789ffbb04351a11'>block</a> experiments seasonality detection
  • another <a href='http://bl.ocks.org/Kcnarf/89e1e69c888e8241ed92'>block</a> experiments autocorrelation
  • another <a href='http://bl.ocks.org/Kcnarf/1e6da47724c39156adb3'>block</a> experiments time series correlation
  • another <a href='http://bl.ocks.org/Kcnarf/0a8fe1caa2ac025c8e86'>block</a> deals with the impact of seasonality when computing the trend of a timeline

Acknowledgments:

mit Licensed

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