OpenCvSharp Build Instructions

July 18, 2026 ยท View on GitHub

Windows

Prerequisites

  • Visual Studio 2022 / 2026, or the corresponding Build Tools, with the Desktop development with C++ workload
  • CMake 3.20+ in PATH (winget install Kitware.CMake)
  • Git in PATH
  • vcpkg in PATH or VCPKG_INSTALLATION_ROOT set 
    git clone https://github.com/microsoft/vcpkg C:\vcpkg
C:\vcpkg\bootstrap-vcpkg.bat
# Add C:\vcpkg to PATH, or set $env:VCPKG_INSTALLATION_ROOT = 'C:\vcpkg'

Steps

  1. Clone the repository with submodules (opencv + opencv_contrib are included as submodules):

    git clone --recursive https://github.com/shimat/opencvsharp.git
cd opencvsharp

    If you already cloned without submodules:

    git submodule update --init --recursive

  2. Build OpenCV from source (Tesseract and other native dependencies are automatically installed via vcpkg):

    # Install vcpkg dependencies (only needed once, or after vcpkg.json changes)
C:\vcpkg\vcpkg.exe install --triplet x64-windows-static --overlay-triplets cmake\triplets --x-install-root vcpkg_installed

    .\scripts\build_opencv_windows.ps1
# Use -Jobs N to control parallel build (default: 4)
.\scripts\build_opencv_windows.ps1 -Jobs 8

    Output is installed to opencv_artifacts/.

  3. Build the native wrapper OpenCvSharpExtern:

    # Use "Visual Studio 17 2022" for VS 2022, or "Visual Studio 18 2026" for VS 2026
cmake -S src -B src\build -G "Visual Studio 18 2026" -A x64 `
      -D "CMAKE_PREFIX_PATH=$PWD\opencv_artifacts" `
      -D CMAKE_TOOLCHAIN_FILE="C:\vcpkg\scripts\buildsystems\vcpkg.cmake" `
      -D VCPKG_TARGET_TRIPLET=x64-windows-static `
      -D "VCPKG_INSTALLED_DIR=$PWD\vcpkg_installed" `
      -D "VCPKG_OVERLAY_TRIPLETS=$PWD\cmake\triplets"
cmake --build src\build --config Release

  4. Build the managed OpenCvSharp library:

    • Open OpenCvSharp.slnx and build (requires Visual Studio 2022 17.12+, or VS 2026), or:
    dotnet build src/OpenCvSharp/OpenCvSharp.csproj -c Release

    Note on the native DLL: Step 3 automatically copies OpenCvSharpExtern.dll into test/OpenCvSharp.Tests/ as a post-build step, so dotnet test works out of the box. For your own application, either add src\build\OpenCvSharpExtern\Release to PATH, or copy OpenCvSharpExtern.dll alongside your app's output directory.

Ubuntu

Tesseract and image libraries (libjpeg-turbo, libpng, libtiff, libwebp) can be managed either via vcpkg (recommended, consistent with Windows) or via the system package manager.

Prerequisites: cmake, git, g++, vcpkg installed.

git clone --recursive https://github.com/shimat/opencvsharp.git
cd opencvsharp
git submodule update --init --recursive

# Install dependencies via vcpkg
/path/to/vcpkg/vcpkg install \
  --triplet x64-linux-static \
  --overlay-triplets cmake/triplets

Build OpenCV and OpenCvSharpExtern pointing to vcpkg:

cmake -C cmake/opencv_build_options.cmake \
      -S opencv -B opencv/build \
      -D OPENCV_EXTRA_MODULES_PATH=$PWD/opencv_contrib/modules \
      -D CMAKE_INSTALL_PREFIX=$PWD/opencv_artifacts \
      -D CMAKE_TOOLCHAIN_FILE=/path/to/vcpkg/scripts/buildsystems/vcpkg.cmake \
      -D VCPKG_TARGET_TRIPLET=x64-linux-static
cmake --build opencv/build -j$(nproc)
cmake --install opencv/build

cmake -S src -B src/build \
      -D CMAKE_BUILD_TYPE=Release \
      -D CMAKE_PREFIX_PATH=$PWD/opencv_artifacts \
      -D CMAKE_TOOLCHAIN_FILE=/path/to/vcpkg/scripts/buildsystems/vcpkg.cmake \
      -D VCPKG_TARGET_TRIPLET=x64-linux-static
cmake --build src/build -j$(nproc)

Option B: system packages (apt)

sudo apt-get install -y g++ cmake libtesseract-dev \
  libjpeg-dev libpng-dev libtiff-dev libwebp-dev \
  libavcodec-dev libavformat-dev libswscale-dev

Build OpenCV from source: https://docs.opencv.org/4.x/d7/d9f/tutorial_linux_install.html

Then build the native wrapper:

cmake -S src -B src/build \
      -D CMAKE_BUILD_TYPE=Release \
      -D CMAKE_PREFIX_PATH=${YOUR_OPENCV_INSTALL_PATH}
cmake --build src/build -j$(nproc)

Add a reference to the built shared library:

export LD_LIBRARY_PATH="${LD_LIBRARY_PATH}:/path/to/opencvsharp/src/build/OpenCvSharpExtern"

Build managed library (both options)

dotnet build src/OpenCvSharp/OpenCvSharp.csproj -c Release

Customizing OpenCV and OpenCvSharp for embedded (ARM) Platforms

If you want to use OpenCV and OpenCvSharp on an embedded platform like a Raspberry Pi with a 64-bit OS, you have to build both libraries manually, and it's easiest to build it right on your target hardware to avoid cross-compiler toolchain challenges. The instructions for this build and install are here.