Grabs image data and converts it to a numpy array

def numpy(self):
        """ Grabs image data and converts it to a numpy array """
        # load GDCM's image reading functionality
        image_reader = gdcm.ImageReader()
        image_reader.SetFileName(self.fname)
        if not image_reader.Read():
            raise IOError("Could not read DICOM image")
        pixel_array = self._gdcm_to_numpy(image_reader.GetImage())
        return pixel_array