Applied Scientific Research

, Volume 56, Issue 2–3, pp 79–102 | Cite as

The fully digital evaluation of photographic PIV recordings

  • Christian Willert
Article

Abstract

The performance of a purely digital evaluation system for photographic PIV recordings is described. High resolution digital images are obtained from the 35 mm negatives using a commonly available slide scanner. Together with the continually improving capabilities of standard computers, this evaluation system is a cost effective alternative to the traditional analog optical/digital (Young's fringe method) and purely optical PIV interrogation systems. Compared to the optical systems the fully digital evaluation can provide a higher spatial resolution while maintaining a similar measurement uncertainty. Using actual PIV recordings absolute measurement uncertainties are obtained and further predictions toward optimal displacement data recovery are made with the aid of Monte-Carlo simulations. Measurement uncertainties are minimized for particle image diameters on the order of 2 pixels while the reduction of the image depth (i.e. bits/pixel) has little effect. The overall performance of the described digital evaluation is compared to two types of optical evaluation systems.

Key words

particle image velocimetry photographic recording high resolution scanner cross-correlation spatial resolution measurement uncertainty 

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Copyright information

© Kluwer Academic Publishers 1996

Authors and Affiliations

  • Christian Willert
    • 1
  1. 1.Center for Quantitative Visualization (CQV)c/o DLR, Institut für StrömungsmechanikGöttingenGermany

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