Using our method,the FFT program needs a little of computer memory to finish the calculation of Fresnel diffraction with the arbitrary interval of sampling and the demanded precision. This method can be extended conveniently to Collins? formula.

• 利用这种方法 ,只要用小容量 FFT程序 ,便能完成任意给定取样间隔或计算精度的菲涅耳衍射及柯林斯公式的计算