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SavitzkyGolayFiltering

LabWindows/CVI

SavitzkyGolayFiltering

Advanced Analysis Library Only

AnalysisLibErrType SavitzkyGolayFiltering (double inputSequence[], ssize_t numberOfElements, int polynomialOrder, int nSidePoints, double weightingVector[], double filteredData[]);

Purpose

Applies a Savitzky-Golay smoothing FIR filter to the sequence inputSequence.

This function smooths a noisy signal using piece-by-piece fitting of a polynomial function to the signal. The fitting is done by least squares minimization. See SavitzkyGolayCoef for how the Savitzky-Golay filter coefficients are obtained to apply them here to produce the filtered signal.

Parameters

Input
Name Type Description
inputSequence double [] The sequence to be filtered.
numberOfElements ssize_t The length of inputSequence.
polynomialOrder int The polynomial order.
nSidePoints int (2*nSidePoints +1) is frameSize, which specifies how many data points to use in the polynomial fitting. frameSize must be greater than polynomialOrder.
weightingVector double [] A weighting vector with length frameSize, used in the least square polynomial fitting. If weightingVector is NULL, the function assumes all points have the equal weight.
Output
Name Type Description
filteredData double [] The data after the filter is applied.

Return Value

Name Type Description
status AnalysisLibErrType A value that specifies the type of error that occurred. Refer to analysis.h for definitions of these constants.

Additional Information

Library: Advanced Analysis Library

Include file: analysis.h

LabWindows/CVI compatibility: LabWindows/CVI 8.1 and later