Algorithm (Envelope)

Origin detects the envelopes in the following steps:

  1. Find out all the points whose first-order derivative is equal to zero in the source data. These points will be called the extreme values.
  2. Perform cubic spline interpolation through these extreme values.
  3. Smooth the interpolated data. The smoothing method employed here is Adjacent-Averaging, which takes the average of a certain number of data points around each point in original data. For more information about the smoothing method, please refer to the algorithm description of the Adjacent-Averaging method.