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Old versions of OpenCvSharp are stored in opencvsharp_2410.

NuGet

Managed libraries

PackageDescriptionLink
OpenCvSharp4OpenCvSharp core librariesNuGet version
OpenCvSharp4.ExtensionsGDI+ ExtensionsNuGet version
OpenCvSharp4.WpfExtensionsWPF ExtensionsNuGet version
OpenCvSharp4.WindowsAll-in-one package for Windows (except UWP)NuGet version

Native bindings

PackageDescriptionLink
OpenCvSharp4.runtime.winNative bindings for Windows x64/x86 (except UWP)NuGet version
OpenCvSharp4.runtime.uwpNative bindings for UWP (Universal Windows Platform) x64/x86/ARMNuGet version
OpenCvSharp4.official.runtime.linux-x64Native bindings for Linux x64NuGet version
OpenCvSharp4.runtime.linux-armNative bindings for Linux ArmNuGet version
OpenCvSharp4.runtime.wasmNative bindings for WebAssemblyNuGet version

Native binding (OpenCvSharpExtern.dll / libOpenCvSharpExtern.so) 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 and Ubuntu are released.

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

OpenCvSharp3-AnyCPU / OpenCvSharp3-WithoutDll / OpenCvSharp-AnyCPU / OpenCvSharp-WithoutDll

Docker images

https://github.com/shimat?tab=packages

Installation

Windows (except UWP)

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

UWP

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

Ubuntu 22.04

Add OpenCvSharp4 and OpenCvSharp4.runtime.ubuntu.22.04.x64 NuGet packages to your project.

dotnet new console -n ConsoleApp01
cd ConsoleApp01
dotnet add package OpenCvSharp4
dotnet add package OpenCvSharp4_.runtime.ubuntu.22.04-x64
# -- edit Program.cs --- # 
dotnet run

Downloads

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

Target OpenCV

Requirements

PS1> Install-WindowsFeature Server-Media-Foundation

OpenCvSharp won't work on Unity and Xamarin platform. For Unity, please consider using OpenCV for Unity or some other solutions.

OpenCvSharp does not support CUDA. If you want to use the CUDA features, you need to customize the native bindings yourself.

Usage

For more details, see samples and Wiki pages.

Always remember to release Mat instances! The using syntax is useful.

// C# 8
// Edge detection by Canny algorithm
using OpenCvSharp;

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

As mentioned above, objects of classes, such as Mat and MatExpr, have unmanaged resources and need to be manually released by calling the Dispose() method. Worst of all, the +, -, *, and other operators create new objects each time, and these objects need to be disposed, or there will be memory leaks. Despite having the using syntax, the code still looks very verbose.

Therefore, a ResourcesTracker class is provided. The ResourcesTracker implements the IDisposable interface, and when the Dispose() method is called, all resources tracked by the ResourcesTracker are disposed. The T() method of ResourcesTracker can trace an object or an array of objects, and the method NewMat() is like T(new Mat(...). All the objects that need to be released can be wrapped with T().For example: t.T(255 - t.T(picMat * 0.8)) . Example code is as following:

using (var t = new ResourcesTracker())
{
    Mat mat1 = t.NewMat(new Size(100, 100), MatType.CV_8UC3, new Scalar(0));
    Mat mat3 = t.T(255-t.T(mat1*0.8));
    Mat[] mats1 = t.T(mat3.Split());
    Mat mat4 = t.NewMat();
    Cv2.Merge(new Mat[] { mats1[0], mats1[1], mats1[2] }, mat4);
}

using (var t = new ResourcesTracker())
{
    var src = t.T(new Mat(@"lenna.png", ImreadModes.Grayscale));
    var dst = t.NewMat();
    Cv2.Canny(src, dst, 50, 200);
    var blurredDst = t.T(dst.Blur(new Size(3, 3)));
    t.T(new Window("src image", src));
    t.T(new Window("dst image", blurredDst));
    Cv2.WaitKey();
}

Features

Code samples

https://github.com/shimat/opencvsharp_samples/

API Documents

http://shimat.github.io/opencvsharp/api/OpenCvSharp.html

OpenCvSharp Build Instructions

Windows

.\download_opencv_windows.ps1

How to customize OpenCV binaries yourself

If you want to use some OpenCV features that are not provided by default in OpenCvSharp (e.g. GPU), you will have to build OpenCV yourself. The binary files of OpenCV for OpenCvSharp for Windows are created in the opencv_files repository. See the README.

Ubuntu

git clone https://github.com/shimat/opencvsharp.git
cd opencvsharp
git fetch --all --tags --prune && git checkout ${OPENCVSHARP_VERSION}

cd opencvsharp/src
mkdir build
cd build
cmake -D CMAKE_INSTALL_PREFIX=${YOUR_OPENCV_INSTALL_PATH} ..
make -j 
make install

You should add reference to opencvsharp/src/build/OpenCvSharpExtern/libOpenCvSharpExtern.so

export LD_LIBRARY_PATH="${LD_LIBRARY_PATH}:/home/shimat/opencvsharp/src/build/OpenCvSharpExtern"

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

Donations

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

https://github.com/sponsors/shimat