Unable to load DLL 'OpenCvSharpExtern' - RaspberryPi 3, Ubuntu, .NET Core

Hi!

I’m trying to run API which uses OpenCVSharp3-AnyCPU (3.2.0.20170210-beta). I run it on a Raspberry Pi 3 with .NET Core (1.2.0-beta-001291-00) and Raspbian GNU/Linux 8.0 (jessie) on the board.

When I try to start my app with dotnet My.API.dll, I get error (actually it invokes ctor of CascadeClassifier):

Unable to load DLL 'OpenCvSharpExtern': The specified module could not be found.
 (Exception from HRESULT: 0x8007007E)
*** An exception has occurred because of P/Invoke. ***
Please check the following:
(1) OpenCV's DLL files exist in the same directory as the executable file.
(2) Visual C++ Redistributable Package has been installed.
(3) The target platform(x86/x64) of OpenCV's DLL files and OpenCvSharp is the same as your project's.

System.DllNotFoundException: Unable to load DLL 'OpenCvSharpExtern': The specified module could not be found.
 (Exception from HRESULT: 0x8007007E)
   at OpenCvSharp.NativeMethods.core_Mat_sizeof()
   at OpenCvSharp.NativeMethods.TryPInvoke()

My folder contains those items:

CoreCompat.System.Drawing.dll
haarcascade_frontalcatface_extended.xml
haarcascade_frontalface_default.xml
My.API.dll
Microsoft.AspNetCore.Hosting.Abstractions.dll
Microsoft.AspNetCore.Hosting.dll
Microsoft.AspNetCore.Hosting.Server.Abstractions.dll
Microsoft.AspNetCore.Http.Abstractions.dll
Microsoft.AspNetCore.Http.dll
Microsoft.AspNetCore.Http.Extensions.dll
Microsoft.AspNetCore.Http.Features.dll
Microsoft.AspNetCore.Owin.dll
Microsoft.AspNetCore.Server.Kestrel.dll
Microsoft.AspNetCore.WebUtilities.dll
Microsoft.DotNet.InternalAbstractions.dll
Microsoft.Extensions.Configuration.Abstractions.dll
Microsoft.Extensions.Configuration.dll
Microsoft.Extensions.Configuration.EnvironmentVariables.dll
Microsoft.Extensions.DependencyInjection.Abstractions.dll
Microsoft.Extensions.DependencyInjection.dll
Microsoft.Extensions.DependencyModel.dll
Microsoft.Extensions.FileProviders.Abstractions.dll
Microsoft.Extensions.FileProviders.Physical.dll
Microsoft.Extensions.FileSystemGlobbing.dll
Microsoft.Extensions.Logging.Abstractions.dll
Microsoft.Extensions.Logging.dll
Microsoft.Extensions.ObjectPool.dll
Microsoft.Extensions.Options.dll
Microsoft.Extensions.PlatformAbstractions.dll
Microsoft.Extensions.Primitives.dll
Microsoft.Net.Http.Headers.dll
Nancy.dll
Newtonsoft.Json.dll
opencv_ffmpeg320_64.dll
OpenCvSharp.Blob.dll
OpenCvSharp.dll
OpenCvSharp.dll.config
OpenCvSharpExtern.dll
refs
System.Collections.NonGeneric.dll
System.Collections.Specialized.dll
System.ComponentModel.Primitives.dll
System.ComponentModel.TypeConverter.dll
System.Data.Common.dll
System.Diagnostics.Contracts.dll
System.Drawing.Primitives.dll
System.Linq.dll
System.Net.WebSockets.dll
System.Runtime.Serialization.Primitives.dll
System.Text.Encodings.Web.dll
System.Xml.XmlSerializer.dll
web.config
x64
x86

I’ve tried to use dlls mapping, so I’ve created OpenCvSharp.dll.config file:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <dllmap os="!windows" dll="opencv_core2410" target="libopencv_core.so.2.4.10" />
  <dllmap os="!windows" dll="opencv_imgproc2410" target="libopencv_imgproc.so.2.4.10" />
</configuration>

[shimat]

The OpenCvSharpExtern.dll that I released may work only on x86/x64 Windows 😢 You have to build OpenCvSharpExtern.dll for your Linux platform. Please get the OpenCvSharp source code files and use cmake.

cmake src

[matjanos]

Thanks a lot for quick reply. I think that it would be useful to prepare a CI process for Linux machines as well. Cheers!