It can be concluded that the parallel illumination and parallel receiving arrangement is the basic one of the shadow moir method and that other arrangements could inevitably produce errors because of the effect of non - parallel factor 分析結果表明,平行照射平行觀察光場是影柵云紋法中的基本光場,其他光場均受非平行光因素的影響,不可避免地引入誤差。