Discussion of wavefront reconstruction algorithm of off-axis digital holography

In the study of off-axis digital holography, digital hologram may be considered as a light wave field which is illuminated by the unit amplitude plane wave. The Fresnel diffraction integral can be calculated by only one fast Fourier transform (FFT). It is the most popular method of wavefront reconstruction (called 1-FFT). However, applying the spherical wave as the reconstruction wave, there is another method of wavefront reconstruction using the angular spectral diffraction theory and image plane filtering. This method requires four fast Fourier transforms (called FIMG4FFT). Two methods are researched based on the fast Fourier transform theory. The result demonstrates that the FIMG4FFT method needs four FFTs, but it can use less computation resource to reconstruct the equivalent quality object wave field. Finally, the application examples of the FIMG4FFT method are shown in detail in the reconstruction of color digital holograms and micro deformation detection.