how to get vtkImageViewer2 PlaneAxes differently and convert output image to bitmap or bitmapsource

what im trying to do is a way to get image produced by vtkImageViewer and process on it.

i have done this so far but it seems not working:
vtkImageData data = _viewer.GetInput();
Bitmap bitmap = data.ToBitmap();

i get this exception when i run the code : Invalid Number of Scalar Components

what do miss? what should i do??