NAME¶
gpiv - Analyzes images obtained from a fluid flow by Particle Image Velocimetry.
SYNOPSIS¶
gpiv [
-? | --help] [
--usage] [
--console_bins
BINS] [
--console_tooltips] [
--console_view_gpivbuttons] [
--console_view_tabulator] [
--display_background INT] [
--display_intregs] [
--display_piv] [
--display_stretch] [
--display_scalar
INT] [
--display_vectorscale SCALE] [
--display_view_menubar] [
--display_view_rulers] [
--display_zoomscale SCALE] [
--hdf] [
--img_fmt]
[
--mpi_nodes] [-p |
--print] [
--process_imgproc] [
--process_piv] [
--process_gradient]
[
--process_resstatst] [
--process_errvec] [
--process_peaklock] [
--process_average] [
--process_scale] [
--process_substract] [
--process_vorstra] [
IMAGE1,
IMAGE2,
...]
DESCRIPTION¶
Gpiv is a Graphic User Interface program for recording and analyzing
images obtained from a fluid flow that has been seeded with tracer particles
by the so-called Particle Image Velocimetry (PIV) technique. It allows to have
a quick overview of the process settings, easily changing them, executing the
processes, visualizing and optimizing their results in an interactive way. The
processes that may be performed are image recording, interrogation (resulting
into PIV estimators), validation and post-processing of the PIV estimators.
The settings for the PIV processes are subsequently searched in
~/.gpivrc
or in
gpiv.conf (system wide), which is provided by libgpiv.
For recording images,
gpiv recognizes (CCD) cameras that are
IIDC-compliant and connected to the Computer with the IEEE1394 or Firewire
protocol.
In case
gpiv will trigger a camera and lasers, it uses a kernel module
gpivtrig_rtl from the gpivtrig package that depends on the Real Time
Application Interface (RTAI) and RealTimeLinux. Trigger pulses are send to the
parallel port of the Computer (/dev/lpt0 or /dev/lpt1; see the configure
script of the gpivtrig package) at bins #1 (camera), #2 and #3 (first and
second laser respectively). The program may be started directly if all modules
have been loaded or by the gpiv_control script, also included in the gpivtrig
package, which takes care of the loading and unloading of the needed kernel
modules. Currently, the trigger system is tested with RTAI-3.1 and the linux
kernel-2.4.27.
The parameters and options to be used for
gpiv are obtained from
~/.gnome2/gpiv or default settings are to be used if absent. The settings may
be changed or updated by menu->settings->preferences. The parameters of
gpiv (not the PIV process settings) may be overruled by the command
line options, as explained below.
When
gpiv is used on a (Beowulf, distributed memory) cluster, the
MPI-parallelised program
gpiv_rr from the gpivtools package is invoked
using
mpirun. The
gpiv program, however, is launched in the
normal way, without invoking
mpirun.
Options¶
- -? | --help
- On-line help. Besides the options of gpiv it also
shows the additional GNOME, GTK and GNOME GUI options.
- --usage
- Display a brief usage message.
- --console_bins BINS
- Number of bins for histograms of estimators at sub-pixel
level, performed by the peaklock process and of the median residues,
performed by the errvec process.
- -t | --console_tooltips
- Show tooltips.
- --console_view_gpivbuttons
- View the gpiv buttons of the application.
- --console_view_tabulator
- View the tabulator of the application containing all PIV
process settings.
- --display_background INT
- Displaying of background: INT = 0: darkblue
INT = 1: black INT = 2: first frame of image INT = 3:
second frame of image
- --display_intregs
- Enables displaying of interrogation regions.
- --display_piv
- Displaying of PIV data.
- --display_stretch
- Enables automatic stretching of the display when zooming.
- --display_scalar INT
- Display derived quantities from PIV data: INT = 0:
none INT = 1: vorticity INT = 2: shear strain INT =
3: normal strain
- --display_view_menubar
- Enables displaying of the menubar.
- --display_view_rulers
- Enables displaying of the ruler.
- --display_vectorscale SCALE
- Display vector with index: SCALE = 0: magnification
factor = 1, SCALE = 1: magnification factor = 2, SCALE = 2:
magnification factor = 4, SCALE = 3: magnification factor = 8,
SCALE = 4: magnification factor = 16, SCALE = 5:
magnification factor = 32, SCALE = 3: magnification factor = 64,
SCALE = 4: magnification factor = 128, SCALE = 5:
magnification factor = 256.
- -z | --display_zoomscale SCALE
- Display zoom with index: SCALE = 0: magnification
factor = 0.5, SCALE = 1: magnification factor = 0.83, SCALE
= 2: magnification factor = 1.0, SCALE = 3: magnification factor =
1.3, SCALE = 4: magnification factor = 1.6, SCALE = 5:
magnification factor = 2.0.
- --hdf
- Save data in HDF5 format with .gpi extension.
- --img_fmt INT
- store (modified) image data and header in: INT = 0:
PNG format, INT = 1: raw format, INT = 2: HDF5 format,
included with the resulting PIV and post-processing data with .gpi
extension.
- --mpi_nodes INT
- To define the number of nodes when used on a cluster. Used
by mpirun -np INT.
- -p | --print
- Print process parameter settings to stdout.
- --process_imgproc
- Includes image processing in the chain-process.
- --process_piv
- Includes piv interrogation in the chain-process.
- --process_gradient
- Includes testing on the displacement gradient within
interrogation area in the chain-process.
- --process_resstatst
- Includes calculation of statistics of displacement
residuals in the chain-process.
- --process_errvec
- Includes validation on PIV data in the chain-process.
- --process_peaklock
- Includes peak lock in the chain- process.
- --process_average
- Includes calculation of the whole field average PIV
displacements in the chain-process.
- --process_scale
- Includes scaling in the chain-process.
- --process_subtract
- Includes substracting of the whole field average PIV
displacements in the chain-process.
- --process_vorstra
- Includes calculation of vorticity in the chain-process.
- IMAGE1, IMAGE2, ...
- Loads IMAGE1, IMAGE2, ... from a file or from
an URI using the Gnome Virtual File System. The maximum allowed image
dimensions and quantity to be loaded are defined by the program as
described in gpiv_gui.h or by the 'configure' script during the building
of gpiv.
SEE ALSO¶
On-line documentation at
http://gpiv.sourceforge.net/gpiv_doc/index.html or from
the help-menu of
gpiv, gpiv_control(1) and
gpivtools(1).
AUTHOR¶
Gerber Van der Graaf