Provided by: opendrop_3.3.2-3_amd64 
NAME
opendrop - OpenDrop
RELEASE BUILDS
Stand-alone builds for Windows are provided for certain major releases and do not require the
installation of additional software: <https://github.com/jdber1/opendrop/releases/>.
Releases for Linux and macOS don't exist yet and OpenDrop should instead be installed as a Python
package. See next section.
BUILDING PACKAGE FROM SOURCE
OpenDrop requires Python 3.6 or higher, the GTK 3 library, OpenCV Python bindings, and the following
build dependencies:
• Boost.Math
• SUNDIALS ARKODE
Other required Python packages will be automatically installed by pip.
Platform specific build instructions follow.
Ubuntu
1. Install OpenCV.
• If on Ubuntu 17.10 (or later):
sudo apt install python3-opencv
• Alternatively there is an unofficial opencv-python <https://pypi.org/project/opencv-python/> package
that can be installed using pip:
pip3 install opencv-python
2. Install SUNDIALS. Unfortunately libsundials-dev from the Ubuntu repositories are too old, we require
at least version 4.0.0 and above. Here are brief instructions for installing SUNDIALS from source.
1. Download the latest version from the releases page <https://computing.llnl.gov/projects/sundials/
sundials-software>. (Note: the latest version requires a CMake version newer than available in
Ubuntu < 20.04. If this affects you, try an older version of SUNDIALS like 4.0.0 instead.)
2. Extract and change into the source directory, e.g.:
tar -xvf sundials-5.7.0.tar.gz
cd sundials-5.7.0/
3. Create a build directory:
mkdir build
cd build/
4. Configure, build, and install (make sure cmake and build-essential are installed from the Ubuntu
repos):
cmake \
-DEXAMPLES_INSTALL=OFF \
-DBUILD_ARKODE=ON \
-DBUILD_CVODE=OFF \
-DBUILD_CVODES=OFF \
-DBUILD_IDA=OFF \
-DBUILD_IDAS=OFF \
-DBUILD_KINSOL=OFF \
-DBUILD_STATIC_LIBS=OFF \
-DCMAKE_BUILD_TYPE=Release \
..
make
sudo make install
3. Install Boost.Math. If on Ubuntu 20.04 or newer, run:
sudo apt install libboost-dev
The libboost-dev package on older versions of Ubuntu is not recent enough and Boost will need to be
installed from source. We need at least Boost 1.71.0.
4. Follow the installation instructions here <https://pygobject.readthedocs.io/en/latest/getting_started
.html#ubuntu-logo-ubuntu-debian-logo-debian> for installing PyGObject and GTK.
5. Use pip to install OpenDrop from the repo:
pip3 install git+https://github.com/jdber1/opendrop.git
Run pip3 uninstall opendrop to uninstall.
6. Run python3 -m opendrop to launch the app.
Fedora
Tested on Fedora 35.
1. Install Python, pip, and OpenCV:
sudo dnf install python3-devel python3-opencv python3-pip
2. Install glib:
sudo dnf install glib2-devel
3. Install SUNDIALS:
sudo dnf install sundials-devel
4. Install Boost:
sudo dnf install boost-devel
5. Use pip to install OpenDrop from the repo:
pip install git+https://github.com/jdber1/opendrop.git
Run pip uninstall opendrop to uninstall.
6. Run python -m opendrop to launch the app.
macOS
1. Install the latest version of Python 3 and pip. You can do so using a third-party package manager like
MacPorts <https://www.macports.org/> or Homebrew <https://brew.sh/>.
2.
• Install the unofficial opencv-python <https://pypi.org/project/opencv-python/> package by running:
pip install opencv-python
(Make sure pip refers to your Python 3's pip installation.)
• Alternatively, OpenCV and its python bindings can also be installed using the opencv Homebrew
formula <https://formulae.brew.sh/formula/opencv> or opencv MacPorts port <https://www.macports.org/
ports.php?by=library&substr=opencv>.
3.
• If Homebrew was used to install Python 3, PyGObject and GTK can also be installed by running:
brew install pygobject3 gtk+3
• or if MacPorts was used, run:
sudo port install py36-gobject3 gtk3
(Instead of the py36- prefix, use py37- or py38- if Python 3.7/3.8 is the version installed.)
4. Install Boost.Math and SUNDIALS. (todo: Add MacPorts and Homebrew example).
4. Use pip to install OpenDrop from the repo:
pip install git+https://github.com/jdber1/opendrop.git
Run pip uninstall opendrop to uninstall.
5. Run python3 -m opendrop to launch the app.
Windows
Installing OpenDrop as a Python package is possible on Windows using platforms like MSYS2 or Anaconda.
The process is not very straightforward so your mileage may vary. (todo: This page is out of date and
should be updated.)
When OpenDrop is launched, the Main Menu window will first appear. [image: Main Menu window] [image]
Click on either of the 'Interfacial Tension' or 'Contact Angle' buttons to begin a new analysis of the
respective type.
INTERFACIAL TENSION
A wizard-style window will guide you through the process of performing an interfacial tension analysis.
Image acquisition
First, choose an image input method. OpenDrop currently supports opening images from the local filesystem
or capturing images with a USB camera.
Local filesystem
[image: IFT Image acquisition, local filesystem] [image]
Click on 'Choose files' to open the file chooser dialog and select an individual image or a sequence of
images. When analysing a sequence of images, 'Frame interval' refers to the time interval (in seconds)
between each image. Sequences of images are ordered in lexicographic order.
USB camera
[image: IFT Image acquisition, USB camera] [image]
Click on 'Connect camera' to open the camera chooser dialog. [image: IFT Image acquisition, USB camera
chooser dialog] [image]
OpenDrop uses OpenCV to capture images from a connected camera. 'Camera index' refers to the device index
argument passed to the OpenCV function cv2.VideoCapture(). An index of 0 refers to the first connected
camera (usually a laptop's in-built webcam if present), an index of 1 refers to the second camera, and so
on. Currently, there does not appear to be a way in OpenCV to query a list of valid device indices and
associated device names, so in a multi-camera setup, some trial-and-error is required.
'Frame interval' refers to the time interval (in seconds) between capturing images.
Physical parameters
[image: IFT Physical parameters] [image]
'Inner density' refers to the density of the drop.
'Outer density' refers to the density of the surrounding medium.
'Needle diameter' refers to the diameter of the needle the drop is suspended from.
'Gravity' refers to the gravitational acceleration.
Image processing
[image: IFT Image processing] [image]
The image processing window requires you to define the 'drop region' and 'needle region' of the image.
Click on the 'Drop region' or 'Needle region' buttons in the 'Tools' panel, then drag over the image
preview to define the associated region. [image: IFT Image processing, regions defined] [image]
Once each region is defined, a blue outline will be drawn over the preview showing the drop or needle
profile that has been extracted.
OpenDrop uses OpenCV's Canny edge detector to detect edges in the image, click on the 'Edge detection'
button in the 'Tools' panel to open a dialog bubble which will allow you to adjust the lower and upper
threshold parameters of the Canny edge detector. Thin blue lines are drawn over the preview to show
detected edges.
The extracted needle profile is used to determine the diameter in pixels of the needle in the image.
Along with the needle diameter in millimetres given in the 'Physical parameters' page, a metres-per-pixel
scale can be determined, which is then used to derive other physical properties of the drop after the
image is analysed.
Click on 'Start analysis' to begin analysing the input images, or begin capturing and analysing images if
using a camera.
Results
[image: IFT Results] [image]
The results page shows the current status of the analysis. Data shown in the window is updated as the
analysis progresses.
There are two main views, the 'Individual Fit' view and the 'Graphs' view. The 'Graphs' view is not
available when analysing a single image.
Individual Fit
The 'Individual Fit' view shows analysis details for an individual image. Pick an analysis in the lower
panel to preview its details in the upper panel.
The 'Drop profile' tab on the right of the upper panel shows the fitted drop profile (drawn in magenta)
over the extracted drop profile (drawn in blue). [image: IFT Results, drop profile] [image]
The 'Fit residuals' tab shows a plot of the fit residuals. The horizontal axis is the 'drop profile
parameter', ranging from 0 to 1, with 0 corresponding to one end of the drop edge outline, and 1
corresponding to the other end. The vertical axis is some dimensionless quantity indicating the deviation
of the extracted profile from the fitted profile. [image: IFT Results, fit residuals] [image]
The 'Log' tab shows the history of any messages logged by the fitting routine. [image: IFT Results, log]
[image]
Graphs
[image: IFT Results, graphs] [image]
The 'Graphs' view shows plots of interfacial tension, volume, and surface area over time.
Cancel or discard analysis
You may cancel an in progress analysis by clicking on the 'Cancel' button in the footer (not shown in the
screenshots above). To discard the results of a finished analysis, click the 'Back' button, which will
return you to the 'Image processing' page, or close the window to return to the Main Menu.
Saving
[image: IFT Save dialog] [image]
Once an analysis is finished, click on the 'Save' button in the footer to open the save dialog. All data
will be saved in a folder with name determined by the 'Name' entry, and in a parent directory determined
by the 'Parent' selection.
As a convenience, you may choose to save some pre-made plots. [image: IFT Example save output] [image]
An example save output is shown above, and screenshots of the contents of some files are shown below.
[image: IFT timeline.csv screenshot] [image] timeline.csv.UNINDENT
[image: IFT profile_fit.csv screenshot] [image] water_in_air1/profile_fit.csv (each row is an (x, y)
coordinate pair).UNINDENT
[image: IFT profile_extracted.csv screenshot] [image] water_in_air1/profile_extracted.csv (each row is
an (x, y) coordinate pair).UNINDENT
[image: IFT profile_fit_residuals.csv screenshot] [image] water_in_air1/profile_fit_residuals.csv
(first column is 'drop profile parameter', second column is residual).UNINDENT
[image: IFT params.ini screenshot] [image] water_in_air1/params.ini.UNINDENT
CONTACT ANGLE
A wizard-style window will guide you through the process of performing a contact angle analysis.
Image acquisition
The contact angle image acquisition page is the same as the one for interfacial tension analyses.
Image processing
[image: Contact Angle Image processing] [image]
The image processing window requires you to define the 'drop region' and 'surface line' of the image.
Click on the 'Drop region' button in the 'Tools' panel then drag over the image preview to define the
region. Similarly, click on the 'Surface line' button and drag a line to define the surface that the drop
is sitting on. With the 'Surface line' button depressed and the preview widget focused, use the arrow
keys for finer adjustments of the surface line. [image: Contact Angle Image processing, regions defined]
[image]
Once the drop region is defined, a blue outline will be drawn over the preview showing the drop profile
that has been extracted.
The intersection angle between the drop profile and the surface line will be the contact angle measured.
In a contact angle analysis, OpenDrop uses image thresholding to separate the foreground from the
background. Click on the 'Foreground detection' button to open a dialog bubble which will allow you to
adjust the threshold value. A blue overlay is painted over parts of the image deemed to be in the
foreground.
Click on 'Start analysis' to begin analysing the input images, or begin capturing and analysing images if
using a camera.
Results
[image: Contact Angle Results] [image]
The results page for a contact angle analysis is quite simple.
A summary table is shown on the bottom half with a results visualizer on the top half. Graphs of the left
and right contact angles are also available if more than one image is analysed.
Saving
[image: Contact Angle Save dialog] [image]
Once an analysis is finished, click on the 'Save' button in the footer to open the save dialog. All data
will be saved in a folder with name determined by the 'Name' entry, and in a parent directory determined
by the 'Parent' selection.
As a convenience, you may choose to save some pre-made plots. [image: Contact Angle Example save output]
[image]
An example save output is shown above, and screenshots of the contents of some files are shown below.
(All coordinates are with respect to the origin being on the top-left corner of the image with increasing
x and y in the right and down directions respectively.)
[image: Contact Angle timeline.csv screenshot] [image] timeline.csv.UNINDENT
[image: Contact Angle profile_extracted.csv screenshot] [image] drop1/profile_extracted.csv (each row
is an (x, y) coordinate pair).UNINDENT
[image: Contact Angle surface.csv screenshot] [image] drop1/surface.csv (The coefficients of the
surface line; first column is gradient, second column is y-intercept).UNINDENT
[image: Contact Angle tangents.csv screenshot] [image] drop1/tangents.csv (The coefficients of the
tangent lines at the contact point. First row is left tangent, second row is right tangent. First
column is gradient, second column is y-intercept).UNINDENT
GENICAM INTEGRATION
Install a GenTL producer, (e.g. see harvesters README <https://github.com/genicam/harvesters#
installing-a-gentl-producer>).
OpenDrop checks the environment variable GENICAM_GENTL64_PATH (specified by the GenTL standard) for GenTL
producers. To verify that a GenTL producer is installed correctly, you can run:
$ echo $GENICAM_GENTL64_PATH
/opt/mvIMPACT_Acquire/lib/x86_64
(todo: Add details.)
NOTES
User input validation is not yet implemented, invalid user input may cause OpenDrop to crash or print
errors to the console.
Stub. [image]
[image]
<https://doi.org/10.21105/joss.02604>
OpenDrop is a fully-featured image analysis software for performing pendant drop tensiometry and contact
angle measurements. Images can be loaded from the file system or acquired directly from USB webcams or
GenICam (GigE Vision, USB3 Vision) compliant industrial cameras.
The software is released under the GNU GPL open source license, and available for free.
For installation instructions, see "Installation <>".
----
Git repo:
<https://github.com/jdber1/opendrop/>
Questions, issues, or feedback:
<https://github.com/jdber1/opendrop/issues>
Author
OpenDrop Contributors
Copyright
OpenDrop Contributors
Sep 24, 2025 OPENDROP(1)