[vtkusers] Convert OpenCV Mat to vtkImageData

[Ronald van Duren]

Dear VTK Community,


I'm trying to run several computer vision algorithms on a serie of video frames. But because these algorithms result in some very strange output I figured there might be something wrong with my video frames. So to check if the frames are correct I want to visualize them with VTK. VTK doesn't support the Mat type so I convert the Mat(the video frames) to vtkImageData, but vtkImageData is just shown as a white rectangle.

I get the video frames by converting infrared frames to an openCV Mat type like this.

 openni::Grayscale16Pixel* imgBuf = (openni::Grayscale16Pixel*)irFrame.getData();

int w = irFrame.getWidth();
int h = irFrame.getHeight();
cv::Mat frameOne(h, w, CV_16U, imgBuf);
frameOne.convertTo(frameOne, CV_8U);

I then try to convert the Mat to vtkImageData like this.

vtkSmartPointer<vtkImageData> convertMatToVtkImageData(const Mat &source)
 {
     vtkSmartPointer<vtkImageData> output =    vtkSmartPointer<vtkImageData>::New();
    vtkSmartPointer<vtkInformation> outInfo = vtkSmartPointer<vtkInformation>::New();

output->SetDimensions(source.cols, source.rows, 1);
output->AllocateScalars(VTK_UNSIGNED_CHAR, source.channels());

unsigned char* dptr = reinterpret_cast<unsigned char*>(output->GetScalarPointer());
size_t elem_step = output->GetIncrements()[1]/sizeof(unsigned char);

for (int y = 0; y < source.rows; ++y)
{
    unsigned char* drow = dptr + elem_step * y;
    const unsigned char *srow = source.ptr<unsigned char>(y);
    for (int x = 0; x < source.cols; ++x)
        drow[x] = *srow++;
}

output->Modified();
return output;
}

Is there something wrong with my code or am I trying to do something that is not possible?

Some extra info:

  *   I use Android and do most of the programming in C++ (NDK)
  *   I make use of the Structure Sensor's IR sensor to get the video frames
  *   I cannot use the vtkImageImporter

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