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.NET Framework wrapper for OpenCV
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shimat Merge pull request #865 from shimat/east
add test of EastTextDetection
Latest commit d59ac1a Feb 14, 2020

OpenCvSharp CircleCI Build status Actions Status GitHub license

Cross platform wrapper of OpenCV for .NET Framework.

Old versions of OpenCvSharp are stored in opencvsharp_2410.



Package Description Link
OpenCvSharp4 OpenCvSharp core libraries NuGet version
OpenCvSharp4.Windows All-in-one package for Windows (except UWP) NuGet version Native bindings for Windows x64/x86 (except UWP) NuGet version
OpenCvSharp4.runtime.uwp Native bindings for UWP (Universal Windows Platform) x64/x86/ARM NuGet version
OpenCvSharp4.runtime.ubuntu.18.04-x64 Native bindings for Ubuntu 18.04 x64 NuGet version
OpenCvSharp4.runtime.ubuntu.16.04-x64 (beta) Native bindings for Ubuntu 16.04 x64. This is for Google AppEngine Flexible and made in docker image. NuGet version
(beta packages) Development Build Package

Native binding (OpenCvSharpExtern.dll / is required to work OpenCvSharp. To use OpenCvSharp, you should add both OpenCvSharp4 and OpenCvSharp4.runtime.* packages to your project. Currently, native bindings for Windows, UWP, Ubuntu 18.04 and Ubuntu 16.04 are released.

Packages named OpenCvSharp3-* and OpenCvSharp-* are deprecated.

Windows (except UWP)

Add OpenCvSharp4 and NuGet packages to your project. You can use OpenCvSharp4.Windows instead.


Add OpenCvSharp4 and OpenCvSharp4.runtime.uwp NuGet packages to your project. Note that and OpenCvSharp4.Windows don't work for UWP.

Ubuntu 18.04

Add OpenCvSharp4 and OpenCvSharp4.runtime.ubuntu.18.04.x64 NuGet packages to your project.

dotnet new console -n ConsoleApp01
cd ConsoleApp01
dotnet add package OpenCvSharp4
dotnet add package OpenCvSharp4.runtime.ubuntu.18.04-x64
# -- edit Program.cs --- # 
dotnet run

Ubuntu 16.04 / Google AppEngine Flexible (beta)

Add OpenCvSharp4 and OpenCvSharp4.runtime.ubuntu.16.04.x64 NuGet packages to your project.


If you do not use NuGet, get DLL files from the release page.


OpenCvSharp may not work on Unity platform. Please consider using OpenCV for Unity

Code samples




For more details, see samples and Wiki pages.

// Edge detection by Canny algorithm
using OpenCvSharp;

class Program 
    static void Main() 
        Mat src = new Mat("lenna.png", ImreadModes.Grayscale);
        // Mat src = Cv2.ImRead("lenna.png", ImreadModes.Grayscale);
        Mat dst = new Mat();
        Cv2.Canny(src, dst, 50, 200);
        using (new Window("src image", src)) 
        using (new Window("dst image", dst)) 


  • OpenCvSharp is modeled on the native OpenCV C/C++ API style as much as possible.
  • Many classes of OpenCvSharp implement IDisposable. There is no need to manage unsafe resources.
  • OpenCvSharp does not force object-oriented programming style on you. You can also call native-style OpenCV functions.
  • OpenCvSharp provides functions for converting from Mat into Bitmap(GDI+) or WriteableBitmap(WPF).

OpenCvSharp Build Instructions


  • Install Visual Studio 2019 or later
    • VC++ features are required.
  • Get all submodules
git submodule update --init --recursive
  • Build OpenCvSharp
    • Open OpenCvSharp.sln and build

Ubuntu 18.04

git clone
cd opencvsharp
git fetch --all --tags --prune && git checkout ${OPENCVSHARP_VERSION}
  • Build native wrapper OpenCvSharpExtern
cd opencvsharp/src
mkdir build
cd build
make -j 
make install

You should add reference to opencvsharp/src/build/OpenCvSharpExtern/

export LD_LIBRARY_PATH="${LD_LIBRARY_PATH}:/home/shimat/opencvsharp/src/build/OpenCvSharpExtern"
  • Add OpenCvSharp4 NuGet package to your project
dotnet new console -n ConsoleApp01
cd ConsoleApp01
dotnet add package OpenCvSharp4
# -- edit Program.cs --- # 
dotnet run

Older Ubuntu

Refer to the Dockerfile and Wiki pages.


Licensed under the BSD 3-Clause License.


If you find the OpenCvSharp library useful and would like to show your gratitude by donating, here are some donation options. Thank you.

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