No announcement yet.

QuickSAND update (Butterworth, bug fixes, etc.)

This topic is closed.
  • Filter
  • Time
  • Show
Clear All
new posts

  • QuickSAND update (Butterworth, bug fixes, etc.)

    I have updated QuickSAND (, a freeware package
    for the automated Quick Smoothing And Numerical Differentiation. The
    software if for PowerMacs and clones only.

    Changes include:
    -one new routine (Butterworth filter with automatic finding of optimal
    cutoff frequency)
    -interface enhancements, including (1) the addition of a results window
    that outputs important coefficients (cutoff frequencies, etc.), (2)
    unlimited sample size
    -3 bug fixes (instability of LAMBDA, 1st derivative of LAMBDA, and location
    of saved file):

    Routines include:
    1. Woltring implementation of Generalized Cross-Validatory Spline Smoothing
    and Differentiation (Woltring 1986).
    2. Kasarov-Pantos approximation of the optimal Wiener filter (Gazzani 1994).
    3. LAMBDA (Linear-phase Autoregressive Model-Based Derivative Assessment
    Algorithm) (D'Amico & Ferrigno 1990, 1992). A filter based on the Power
    density spectrum.
    4. Piecewise polynomial of any odd-piecelength and polynomial order up to
    20 (Lanshammar 1982).
    5. 4th central difference smoothing and differentiation (Lanczos 1957).
    6. Optimal Bidirectional 2nd order Butterworth digital Filter (Winter 1990)
    using autocorrelation analyis (Cappello et al. 1996).

    Cappello A, La Palombara PF, Leardini A. 1996. Optimization and smoothing
    techniques in movement analysis. International Journal of Bio-Medical
    Computing 41: 137-151.

    D'Amico M, Ferrigno G. 1990. Technique for the evaluation of derivatives
    from noisy biomechanical displacement data using a model-based
    bandwidth-selection procedure. Medical & Biological Engineering & Computing
    28: 407-415.

    D'Amico M, Ferrigno G. 1992. Comparison between the more recent techniques
    for smoothing and derivative assessment in biomechanics. Medical &
    Biological Engineering & Computing 30: 193-204.

    Gazzani F. 1994. Comparative assessment of some algorithms for
    differentiating noisy biomechanical data. International Journal of
    Bio-Medical Computing 37: 57-76.

    Lanczos C. 1957. Applied Analysis. London: Isaac Pitman & Sons. Reprinted
    by Dover, 1988.

    Lanshammar H. 1982. On practical evaluation of differentiation techniques
    for human gait analysis. Journal of Biomechanics 15: 99-105.

    Winter DA. 1990. Biomechanics and Motor Control of Human Movement. New
    York: John Wiley & Sons.

    Woltring HJ. 1986. A Fortran package for generalized, cross-validatory
    spline smoothing and differentiation. Advances in Engineering Software 8:


    Jeff Walker

    Jeff Walker
    Dept. of Zoology
    Field Museum of Natural History
    Roosevelt Rd. at Lake Shore Dr.
    Chicago, IL 60605, USA
    phone: 312-922-9410 x537 fax: 312-427-7269

    "I like practical applications in mathematics, rather than speculating
    about the first ten to the minus something seconds of the universe.
    Cosmology seems to be almost too close to theology to be interesting.
    To me, it is not quite science, but more like creation myth."

    - Sir James Lighthill