GPIV_PEAKLCK(1)
NAME
gpiv_peaklck - Tests PIV data on the so-called peak-locking effect by
printing/displaying an histogram of the particle displacements at subpixel level.
SYNOPSIS
gpiv_peaklck [-g] [-h | --help] [-n N] [-p | --print] [-v | --version] [filename] < stdin > stdout
DESCRIPTION
Peak-locking effects in Particle Image Velocimetry (PIV) result into
estimations of the particle displacements that are mainly at an integer
number of pixels, instead of at sub-pixel displacements. This effect
may due to stretching of the (round) pixel images, due to a too low
resolution of the pixel-image or may be due to signal interferences of
the data from camera to frame grabber. Gpiv_Peaklck calculates the
particle displacement distribution at sub-pixel level in between 0.0 an
1.0 (0 included, 1 excluded). If peak locking occurs, a non-uniform
distribution of the estimated particle displacements at sub-pixel level
will be found.
The configuration parameters (containing the VALID key) may be overruled by the command line options, as explained below.
Options
-g Graphical visualization of the histogram with gnuplot.
- -h | --help
- On-line help
- -n N Override number of bins (default 10, hard coded).
- -p | --print
- Print parameters, command line options and eventually used input and output filenames to stdout. The output is identic of filename.par, in case -f is used.
- -v | --version
- Print version information on standard output, then exit successfully.
- filename
- Input PIV data file. Overrides stdin and stdout. Output will be written to filename.plk. The parameters will be written or appended to filename.par and may be used for future use by including them in ./gpivrc.
SEE ALSO
gpivtools
AUTHOR
Gerber Van der Graaf
BUGS
- The program seems to work fine with real PIV data. So far, no serious
bugs have been found.