NLT and extrapolated DLT: 3-D cinematography alternatives for enlarging the volume of calibration

Richard N. Hinrichs, Scott P. McLean

    Research output: Contribution to journalArticle

    18 Scopus citations


    This study investigated the accuracy of the direct linear transformation (DLT) and non-linear transformation (NLT) methods of 3-D cinematography/videography. A comparison of standard DLT, extrapolated DLT, and NLT calibrations showed the standard (non-extrapolated) DLT to be the most accurate, especially when a large number of control points (40-60) were used. The NLT was more accurate than the extrapolated DLT when the level of extrapolation exceeded 100%. The results indicated that when possible one should use the DLT with a control object sufficiently large as to encompass the entire activity being studied. However, in situations where the activity volume exceeds the size of one's DLT control object, the NLT method should be considered.

    Original languageEnglish (US)
    Pages (from-to)1219-1223
    Number of pages5
    JournalJournal of Biomechanics
    Issue number10
    StatePublished - Oct 1995



    • Cinematography
    • Direct linear transformation
    • Kinematics

    ASJC Scopus subject areas

    • Biophysics
    • Orthopedics and Sports Medicine
    • Biomedical Engineering
    • Rehabilitation

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