ABSTRACT
Diffraction calculation is the most important calculation in computer holography. The angular spectrum method is also important because it gives a physical interpretation that diffraction calculation can be expressed by the superposition of plane waves. Fresnel diffraction plays an important role in computer holography as well as the angular spectrum method. Fraunhofer diffraction is used for the calculation of the far diffraction region. In holography, diffraction calculation is heavily used, so it is redundant to describe the integral equations of diffraction every time. When implementing the fast Fourier transform-based diffraction calculation of the convolution form, zero padding is necessary. In numerical diffraction calculation, it is necessary to pay attention to aliasing that is caused by discretization. In Fourier optics, diffraction calculations are categorized into two forms: the first is convolution-based diffraction and the second is Fourier transform-based diffraction.
