[Insight-users] help:How to get the gray value of a special point based ITK or VTK

[杜 建军]

friends:
    I am developping a project based on ITK,VTK and VC6. Now,I want to get the grey value of some points on png/bmp/dicom/jepg images.
    In ITK, defined ReaderType::Pointer reader = ReaderType::New();,  then reader->SetFileName( csFilePath ); ,so "reader" has had all information about the image. Now, how to get the gray value of a seed point.
    In VTK, defined vtkImageData *m_vtkImageData; ,when the valuable has the data of image. I meet the same question.
    give me some advices,please.

sincerely
                                                   D.J.J