International Society of Biomechanics
Gold sponsor

Signal Processing Software

GCVSPL: Spline Smoothing & Differentiation, GGLPEX: Extrapolation, QuickSAND: Smoothing and Differentiation, BioProc: Analog data processing.

Jim Dowling

Software and data used in the workshop on Data Smoothing during the 1999 ISBS Congress in Perth, Australia:

default deriverr.exe (124 KB)

default pezzack.dat (1 KB)

Giannis Giakas

Software and data used in the workshop on Data Smoothing during the 1999 ISBS congress in Perth, Australia:

  • Software for automatic filtering and differentiation using the spectrum assessment method. Includes test data files.

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A program to read and display Kistler, APAS and other file formats. Includes algorithms for smoothing and ensemble averaging of signals.

(link out of date - http://isbweb.org/software/bioproc)

Jeff Walker

Quick Smoothing And Numerical Differentiation for Power Macintosh. This software has numerous algorithms for smoothing and differentiating noisy data, including the Woltring spline routines, Butterworth filters, Wiener filters, and more.

(link out of date - http://usm.maine.edu/~walker/software.html)

Giannis Giakas

Software that uses a linear prediction method to extrapolate data.

Abstract

Two extrapolation techniques for recursive digital filtering are presented and compared with common padding methods such as linear and reflection (reverse mirror) extrapolation. The case in which the endpoints of position data lead to peak accelerations after filtering and differentiation is examined. The first technique, "least squares", is based on fitting a third degree polynomial to the final ten data points in both to the forward and backward directions and extending the signal by 20 data points using the polynomial coefficients. The second technique, "prediction", is based on a linear autoregressive model with 20 coefficients, which is applied in both directions and the signal is extrapolated by 20 points. The lowest cumulative error of the endpoint accelerations (22.8 rad s-2) represented just one third of the error when the common padding methods were used in optimal digital filtering (69.7 rad s-2). It also represented approximately half the lowest cumulative error in optimal smoothing with quintic splines (48.0 rad s-2).

default gglpex.exe - Executable F (.exe) file (23 KB)

default gianpred.inf - test description (14 B)

default readme.txt - read me (1 KB)

Tony Reina

A Matlab MEX interface for the GCVSPL and SPLDER packages based on Dwight Meglan's C Code.

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A Matlab MEX interface for the GCVSPL package.

document carta.txt - read me (5 KB)

document carta.zip - source code (41 KB)

ChunXiang Tian

A Matlab MEX interface for the GCVSPL package.

document gcvspl.mex source code (7 KB)

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A version of GCVSPL in the C language.

default gcvspl.c (38 KB)

default gcvspl.h (904 B)

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A version of GCVSPL in the C language.

default meglan.zip (8 KB)

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A front-end program in Fortran 77 (last updated April 12, 2000). The program is interactive and self-explanatory. Tested on UNIX (Sun and SGI) and Windows NT.

pdf filter.pdf (95 KB) - Notes on Digital Filtering

pdf gcvspl.zip (53 KB) - Complete package

Herman J. Woltring

GCVSPL is a Fortran package for spline smoothing and differentiation, by the late Herman J. Woltring. The methods were described in Woltring HJ (1986) A FORTRAN package for generalized, cross-validatory spline smoothing and differentiation. Adv. Engng. Softw. 8:104-113. Woltring has shown that spline smoothing is equivalent to a double Butterworth filter (see Release Notes). The differences are that with splines it is possible to process data with unequal sampling intervals and the boundary conditions are well defined. The original subroutine package is available, as well as versions for C and Matlab programmers. Also some front-end programs for UNIX and PC.

pdf gcvspl.memo (3 KB) - Release Notes (read first)

pdf gcvspl.f (46 KB) - Subroutine package - VMS Fortran version

pdf gcvspl.fortran (54 KB) - Subroutine package - Fortran 77 version

pdf gcvtst.fortran (6 KB) - Demo/Test Program - including Vaughan's falling golf ball data