In1943, Carl Zeiss also developed a procedure to measurelens imagequality with so-called “MTF” curves (modulation transfer function), which numerous manufacturers today use for quality control.
1943年卡尔蔡司同样研发了一套利用MTF（调制传递函数）
2
Four kinds of laser source are used to measure the diffractive efficiency of Fresnel lens.
使用四种不同光源，对菲涅耳透镜的衍射效率进行测试。
3
The method to measure the lens focus with laser speckle is described. The principle of this method is analysed and verified by experiment.