Function TestReadWriteRead

IO/Image/Testing/Python/TestNIFTIReaderWriter.py:122–159

Read, write, and re-read a file, return difference.

(infile, outfile)

    return renwin

def TestReadWriteRead(infile, outfile):
    """Read, write, and re-read a file, return difference."""

    inpath = os.path.join(VTK_DATA_ROOT, "Data", infile)
    outpath = os.path.join(str(VTK_TEMP_DIR), outfile)

    # read a NIFTI file
    reader = vtkNIFTIImageReader()
    reader.SetFileName(inpath)
    reader.TimeAsVectorOn()
    reader.Update()

    writer = vtkNIFTIImageWriter()
    writer.SetInputConnection(reader.GetOutputPort())
    writer.SetFileName(outpath)
    # copy most information directory from the header
    writer.SetNIFTIHeader(reader.GetNIFTIHeader())
    # this information will override the reader's header
    writer.SetQFac(reader.GetQFac())
    writer.SetTimeDimension(reader.GetTimeDimension())
    writer.SetQFormMatrix(reader.GetQFormMatrix())
    writer.SetSFormMatrix(reader.GetSFormMatrix())
    writer.Write()

    reader2 = vtkNIFTIImageReader()
    reader2.SetFileName(outpath)
    reader2.TimeAsVectorOn()
    reader2.Update()

    diff = vtkImageMathematics()
    diff.SetOperationToSubtract()
    diff.SetInputConnection(0,reader.GetOutputPort())
    diff.SetInputConnection(1,reader2.GetOutputPort())
    diff.Update()
    diffrange = diff.GetOutput().GetScalarRange()
    differr = diffrange[0]**2 + diffrange[1]**2

    return differr

for infile, outfile in testfiles:
    err = TestReadWriteRead(infile, outfile)