differention

[Dr._Imad]

Here it is in 6.02
(It takes forever to convert it to 6.02 from 7.1, so I just rewrote it)

[Mike26]

For the Savitzky Golay filter uses an array input while the input i am trying to take the derivative of are numbers. How do i modify Savitzky Golay filter to fit my system? Also, what are the "order" and "window" components of the Savitzky Golay filter?

[SciWare]

Hi Mike

The our Savitzky Golay filter includes a point by point version. Attached is an example of using the point by point filter to obtain smoothed data and a derivative of user defined order.

To smooth the data the algorithm holds a circular buffer of 2m+1 points called the window. As each data point is added to the window a smoothing operation is performed on the data in the buffer and returns a value that represents the smoothed data point at the center of the window. The smoothing operation calculates a least squares polynomial fit to the window to provide the smoothed data point. Since polynomials are easy to differentiate we can also calculate a derivative at the center of the window as long as the derivative is not greater that the polynomial order that we are implementing.

To be able to run the example you will need to also download the Savitzky-Golay filter available from

:www.sciware.com.au

I hope this helps

Regards

Kurt

Message Edited by SciWare on 03-10-2005 06:07 AM