Update on Fuzzy-Logic-Enhanced Digital-PIV Software

Two reports present additional information on the subject matter of "Software for Processing Data in Particle-Image Velocimetry" (LEW-16857),NASA Tech Briefs, Vol. 24, No. 1 (January 2000), page 26a. Like the cited prior article, both reports discuss the principles and the practical aspects of particle-image velocimetry (PIV), which is a method of determining a flow velocity field from images of small seed particles that are entrained in the flow and that are illuminated by laser pulses at known intervals of time. Also like the cited prior article, the reports describe PIVPROC -a user-friendly computer program that creates an interactive computing environment for displaying and processing PIV image data and that employs fuzzy logic to maximize the amount and quality of velocity information extracted from the raw data. The cited prior article mentioned in passing that PIVPROC supports the combined use of cross-correlation and particle-tracking image-data-processing techniques to obtain high-quality velocity data over a wide range of particle-seeding densities; the two reports discuss this aspect of PIVPROC in more detail, with some emphasis on the fact that this combination of techniques yields velocities with the highest possible spatial resolution.