FilterDoubleExponentialSmoothing provides an weighted running average filter More...

#include <Filter.h>

Inheritance diagram for alvar::FilterDoubleExponentialSmoothing:

Public Member Functions
	FilterDoubleExponentialSmoothing (double _alpha=0.5, double _gamma=1.0)
double	getGamma ()
virtual double	next (double y)
	Update the value. All inherited classes need to update value in next().
double	operator= (double _value)
void	setGamma (double _gamma)
Protected Attributes
double	gamma
double	slope

Detailed Description

FilterDoubleExponentialSmoothing provides an weighted running average filter

The FilterDoubleExponentialSmoothing calculates a simple running average for both the average and slope using the weight values alpha and gamma.

                value = ((1.0-alpha) * (value + slope)) + (alpha * (double)y);
                slope = ((1.0-gamma) * (slope)) + (gamma * (value - value_prev));

If the weight values (alpha , gamma) are larger (near 1.0) the formulas react faster for changes and if they are near 0.0 then the reaction is slower. The weight values alpha and gamma may be set in the constructor or with setAlpha() and setGamma() .