Unable to find an entry point named aruco_Dictionary_delete

[jerkohren]

Summary of your issue

Hi, i am getting this exception when trying to find ArUco markers. On Windows machine it works without problems. The problem is Raspberry Pi OS.

Environment

PRETTY_NAME="Raspbian GNU/Linux 10 (buster)" NAME="Raspbian GNU/Linux" VERSION_ID="10" VERSION="10 (buster)" VERSION_CODENAME=buster ID=raspbian ID_LIKE=debian

What did you do when you faced the problem?

I tried to add different nuget packages of OpenCvSharp but nithing helps.

Example code:

Here is my methof, exception is thrown on line 19.

   11     public static bool FindArUcoMarker(Mat frame)
   12    {
   13         using var dict = CvAruco.GetPredefinedDictionary(PredefinedDictionaryName.Dict6X6_250);
   14
   15        var param = new DetectorParameters();
   16        CvAruco.DetectMarkers(frame, dict, out var corners, out var ids, param, out var rejectedImgPoints);
   17
   18         Debugging.Debug.DrawArucoMarker(ref frame, corners, ids, new Scalar(255, 0, 0));
   19         return true;
   20   }

Output:

System.EntryPointNotFoundException: Unable to find an entry point named 'aruco_Dictionary_delete' in shared library 'OpenCvSharpExtern'.
   at OpenCvSharp.Internal.NativeMethods.aruco_Dictionary_delete(IntPtr ptr)
   at OpenCvSharp.Aruco.Dictionary.DisposeUnmanaged()
[16:15:17 ERR] Stack Trace:  ---     at OpenCvSharp.Internal.NativeMethods.aruco_Dictionary_delete(IntPtr ptr)
   at OpenCvSharp.Aruco.Dictionary.DisposeUnmanaged()
[16:15:17 ERR] Unable to find an entry point named 'aruco_Dictionary_delete' in shared library 'OpenCvSharpExtern'.
[16:15:17 ERR] *** Global * Exception * Handling ***
[16:15:17 ERR] System.EntryPointNotFoundException: Unable to find an entry point named 'aruco_Dictionary_delete' in shared library 'OpenCvSharpExtern'.
   at OpenCvSharp.Internal.NativeMethods.aruco_Dictionary_delete(IntPtr ptr)
   at OpenCvSharp.Aruco.Dictionary.DisposeUnmanaged()
   at OpenCvSharp.DisposableObject.Dispose(Boolean disposing)
   at OpenCvSharp.DisposableObject.Dispose()
   at ....ArUcoMarkerDetector.FindArUcoMarker(Mat frame) in C:\...\ArUcoMarkerDetector.cs:line 19
   at ...Worker.Start() in C:\....CvWorker.cs:line 294

What did you intend to be?

I have installed this nuget packages:

<PackageReference Include="OpenCvSharp4" Version="4.7.0.20230115" />
<PackageReference Include="OpenCvSharp4.Extensions" Version="4.7.0.20230115" />
<PackageReference Include="OpenCvSharp4.runtime.linux-arm" Version="4.7.0.20230115" />
<PackageReference Include="OpenCvSharp4.WpfExtensions" Version="4.7.0.20230115" />

[jerkohren]

I have found a cause. It is in line: using var dict = CvAruco.GetPredefinedDictionary(PredefinedDictionaryName.Dict6X6_250); After i removed using keyword, it worked. Can someone explain this please? Here is DrawArucoMarker method: public static void DrawArucoMarker(ref Mat frame, Point2f[][] corners, int[] ids, Scalar size) { var arUcoFrame = frame.Clone(); CvAruco.DrawDetectedMarkers(arUcoFrame, corners, ids, size); Cv2.ImShow("ArUco detector", arUcoFrame); }

[stale[bot]]

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