OpenCV => ImageMagick cv::Mat to Magick::Image CV_UC3

I want to use ImageMagick in order to write a multiframe tiff. I followed this in order to write a "TiffWriter" : Tiffwriter topic

I tried to convert a cv::Mat to a Magick::Image using this topic : cv::Mat => Magick::Image

I face a problem on the second part :

I changed the TiffWritter in order to write RGBImage from OpenCV Matrix like that :

TiffWriter::TiffWriter(std::string filename) : filename(filename) {}

// for example for a 8 bit gray image buffer
void TiffWriter::writeGray(const unsigned char* buffer, int width, int height)
{
    Magick::Blob gray8Blob(buffer, width * height);
    Magick::Geometry size(width, height);
    Magick::Image gray8Image(gray8Blob, size, 8, "GRAY");
    imageList.push_back(gray8Image);
}
void TiffWriter::writeRGB(Mat& mat)
{
    auto depth = mat.depth();
    auto channels = mat.channels();
    auto type = mat.type();
    Magick::Image Mg_RGB(mat.cols,mat.rows,"BGR",Magick::CharPixel,(char *)mat.data);
    imageList.push_back(Mg_RGB);
}



TiffWriter::~TiffWriter()
{
    Magick::writeImages(imageList.begin(), imageList.end(), filename);
}

During execution, i face an error like that :

I tried to check Depth, channels, and type as you can see in spy, and all seems good then i'am a little out of ideas about what can be the problem.

Just before i succeed to display exactly the same image in a window.

for (int i = 16; i < shg.count(); i += 2)
{
    cout << "\n Image " << i << "\n";
    start = chrono::system_clock::now();
    Mat im = shg.GetSubImage(i);
    MaskRCNN.ProcessImage(im);
    // This work !
    cv::imshow("Display window", im);
    cv::waitKey(500);
    end = std::chrono::system_clock::now();
    int elapsed_seconds = std::chrono::duration_cast<std::chrono::seconds>
        (end - start).count();
    cout << "elapsed time: " << elapsed_seconds << "s\n";
}
cvvDestroyWindow("Display window");
// Issue here
shg.Save(Dest_File);

The method in the object encapsuling the images is like that :

bool ImageContainer::Save(cv::String Filepath)
{
    try
    {
        TiffWriter MyTiffWriter(Filepath);
        for (int i = 0; i < count(); i++)
        {
            Mat Im = GetSubImage(i);
            MyTiffWriter.writeRGB(Im);

        }
        cout << Filepath + " Enregistré...\n";
        return true;
    }
    catch (Exception e)
    {
        cout << e.msg;
        return false;
    }
}

Do anybody have an idea ?

Thanks !

The error message detail :

Exception non gérée à 0x00007FFAE241A388 dans Program.exe : exception
Microsoft C++ : Magick::ErrorOption à l'emplacement de mémoire
0x0000003DED95E150.

If i click "continue", i have this message :

Exception levée à 0x0000000000000000 dans Program.exe : 0xC0000005 :
Violation d'accès lors de l'exécution à l'emplacement
0x0000000000000000.Exception levée à 0x0000000000000000 dans Program.exe :
0xC0000005 : Violation d'accès lors de l'exécution à l'emplacement
0x0000000000000000.

EDIT : I handled the exception like that :

void TiffWriter::writeRGB(Mat& mat)
{
    try
    {
    auto depth = mat.depth();
    auto channels = mat.channels();
    auto type = mat.type();
    Magick::Image Mg_RGB(mat.cols, mat.rows, "BGR", Magick::CharPixel, (char *)mat.data);
    imageList.push_back(Mg_RGB);
    }
    catch (Magick::Error &error) 
    { 
        // Process Magick++ file open error 
        cerr << "Error: " << error.what() << endl; 
        // Try next image. 
    }
}

The message is this one :

Error: Magick: unrecognized pixel map ``QSõ▒' @ error/pixel.c/ImportImagePixels/4243

If i replace the line causing problem by :

    Magick::Image Mg_RGB(2, 2, "RGB", Magick::CharPixel, (char*)"2222");

I get exactly the same issue.

I tried inspect "ImageMagick/pixel.c" file : When i watch the code of "pixel.c" line 4243, there is a switch case :

switch (map[i])
    {
      case 'a':
      case 'A':
      {
        quantum_map[i]=AlphaQuantum;
        image->alpha_trait=BlendPixelTrait;
        break;
      }
      case 'B':
      case 'b':
      {
        quantum_map[i]=BlueQuantum;
        break;
      }
      ...
      default:
      {
        quantum_map=(QuantumType *) RelinquishMagickMemory(quantum_map);
        (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
          "UnrecognizedPixelMap","`%s'",map);
        return(MagickFalse);
      }
}

Then it is as if i went in the "default" part of this "switch/case" maybe a problem with "RGB" char ?