Platypus Cradle Removal Algorithm

Platypus is a software solution that comes both as a standalone application and a Photoshop plugin. It is specifically designed to digitally remove cradling artifacts in X-ray images of paintings on panel. This project was made possible thanks to the financial support of the Kress foundation. Read more and download the software below.

Cradle Removal

The Platypus cradle removal algorithm was originally developed by Ph.D. student Rachel Yin at the Department of Mathematics of the Duke University (North Carolina, USA). Rachel worked under the supervision of Professor Ingrid Daubechies. Later her code was translated to a C++ framework by Ph.D. student Gabor Fodor, from the department of Electronics and Informatics (ETRO) at the Vrije Universiteit Brussel (VUB), Belgium. Finally, the C++ code was embedded into a Photoshop plug-in, developed at Digital Film Tools. All three versions of the software, along with their documentation, are publicly available and can be downloaded below.

Package Moved to Flatiron Institute

As of December 2024, the Flatiron Institute is taking over maintanence of the code for Platypus. The applet currently works on mac and linux. The photoshop plugin is in progress.

Building from Source

Prerequisites

You need the following installed before building:

• git
• cmake (3.16+)
• ninja
• A C++17 compiler (Xcode CLI tools on macOS, GCC on Linux, Visual Studio 2022 on Windows)

Quick Start (Recommended)

The provided configure scripts prefer preinstalled OpenCV and Qt6 when available. If they are not found, the scripts fall back to downloading and building the dependencies via vcpkg.

macOS

git clone https://github.com/simonsfoundation/platypus.git
cd platypus
./configure.sh
cmake --build build --target PlatypusGui
./build/PlatypusGui

The script will install ninja via Homebrew if it is not already present.

Linux (Ubuntu/Debian)

Install the required system packages first (vcpkg needs X11/xcb headers to build Qt6's platform plugin):

sudo apt-get install -y pkg-config linux-libc-dev libx11-dev libxext-dev \
  libxrender-dev libxcb1-dev libx11-xcb-dev libxcb-glx0-dev \
  libxkbcommon-dev libxkbcommon-x11-dev libgl1-mesa-dev \
  curl zip unzip tar ninja-build cmake git

Then build:

git clone https://github.com/simonsfoundation/platypus.git
cd platypus
./configure.sh
cmake --build build --target PlatypusGui
./build/PlatypusGui

The configure script checks for missing system packages and tells you exactly what to install if anything is missing.

Windows

Windows end users should download the signed installer .exe from GitHub Releases and install Platypus by double-clicking it. They should not need to install Qt, OpenCV, Visual Studio runtimes, or any other dependency manually.

For local developer builds, use a Developer Command Prompt with Git, CMake, and Visual Studio 2022 (with the C++ workload):

git clone https://github.com/simonsfoundation/platypus.git
cd platypus
configure.bat
cmake --build build --config Release --target PlatypusGui
powershell -ExecutionPolicy Bypass -File scripts\windows_package.ps1 -BuildDir build -Configuration Release -PackageDir build\package

To sign a local installer with Microsoft Trusted Signing:

copy scripts\windows_sign_metadata.sample.json scripts\windows_sign_metadata.local.json
powershell -ExecutionPolicy Bypass -File scripts\windows_package.ps1 -BuildDir build -Configuration Release -PackageDir build\package -Sign -SigningMetadataPath scripts\windows_sign_metadata.local.json

Note: If configure.sh or configure.bat falls back to vcpkg, the first build takes ~30-60 minutes while OpenCV and Qt6 are built from source. Subsequent fallback builds are faster because vcpkg caches compiled packages locally.

The full Windows release workflow, including local signing and installer verification, is documented in installer_guide/windows.md.

Manual Dependency Installation (Alternative)

If you prefer to install dependencies yourself rather than using the configure scripts:

macOS (Homebrew)

brew install opencv qt cmake ninja
cmake -B build -S . -G Ninja \
  -DCMAKE_BUILD_TYPE=Release \
  -DCMAKE_OSX_ARCHITECTURES="$(uname -m)" \
  -DCMAKE_PREFIX_PATH="$(brew --prefix qt)"
cmake --build build --target PlatypusGui

Linux (apt)

sudo apt-get install -y libopencv-dev qt6-base-dev cmake ninja-build
cmake -B build -S . -G Ninja -DCMAKE_BUILD_TYPE=Release
cmake --build build --target PlatypusGui

If qt6-base-dev is not available on your distribution, install the equivalent Qt6 development packages for your distro and point CMake at Qt6 with -DCMAKE_PREFIX_PATH=/path/to/Qt6.

Windows (vcpkg)

See the Windows GitHub Actions workflow for the full set of dependencies and build flags used in CI.