VTK continous display multiple images

I am a newcomer for VTK .I want to display three images,and update it,like video. I use example MultipleViewports show three picture.

• 1.mapper->SetInputConnection(sphereSource->GetOutputPort());,how to change a matrix to type (vtkAlgorithmOutput *input)?
• 2.After renderWindowInteractor->Start();, this program stops. How could I change the image data and fresh it? Another better ideas is welcome. Thanks.