def METHOD_NAME(self, shiftField, scope):
    #self.shiftField = shiftField
    #self.shiftFieldname = sfname
    if self.axis == 'up_down':
        X, Y = np.ogrid[:512, :256]
    else:
        X, Y = np.ogrid[:scope.cam.GetPicWidth()/2, :scope.cam.GetPicHeight()]
    self.X2 = np.round(X - shiftField[0](X*70., Y*70.)/70.).astype('i')
    self.Y2 = np.round(Y - shiftField[1](X*70., Y*70.)/70.).astype('i')