salah wrote: >How can I create and view the histogram of a 3D gray-level Itk-Image? Have a look at the class reference for vtkImageAccumulate (http://www.vtk.org/doc/release/4.0/html/classvtkImageAccumulate.html). There is a link to an example: http://public.kitware.com/cgi-bin/cvsweb.cgi/~checkout~/VTK/Examples/ImageProcessing/Tcl/HistogramWidget.tcl Good luck, Donna