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K-A End User Help

Wavelet II

Wavelet II denoising algorithm does not require resampling of data with a constant time interval. It performs the denoising procedure directly using available data points. With this approach there is no interpolation step to create artificial data points. This algorithm also ignores the minimum gap.

WVII.png

  • Threshold Type — This is an internally calculated (or explicitly set by a user) noise level for a pre-loaded data slice. The threshold is applied to high frequency data points in the denoising process. The value is internally calculated from a pre-loaded data slice when a user navigates to the filter tab. KAPPA-Automate supports two different modes of calculating thresholds in the denoising process.

    • Manual — An initial threshold value is automatically calculated from a data slice selected at the pre-load stage. This same value is then applied to all the data during the denoising process. This works well if the dataset has almost a constant noise level throughout its history. Users can manually change the fixed threshold value directly by typing the required value.

    • Adaptive — In this mode KAPPA-Automate calculates a threshold value for each data slice separately and applies it in the denoising algorithm. Threshold values in adaptive mode are adjusted only by using the Threshold level slide bar. The Threshold level serves as a boost factor that is equally applied to all threshold values internally calculated from pre-loaded data slices.

  • Threshold Level — A Threshold level slide bar is a user interface control device that is used to set a general boost factor applicable to all the automatically calculated threshold values in the adaptive mode. Threshold levels range from +100 to -100. The boost factor value is applied to threshold values using the formula below. It is important to note that manually setting the threshold value (Sigma final) in fixed mode initiates a re-estimation of the initially calculated threshold (Sigma I) using the current filter level. Irrespective of the threshold mode used, only the Sigma final parameter is passed to the denoising procedure.

    σfinal = σi x 10L/50

    where,

    σfinal - threshold value used in the denoising algorithm

    σi - initially calculated threshold

    L - filter level

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