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Detail
Journal Article
Spatial resolution enhancement in holographic imaging via angular spectrum expansion
- Authors
- Byung Gyu Chae
- Issue Date
- 2024-03
- Citation
- Optics Continuum, v.3, no.3, pp.263-277
- ISSN
- 2770-0208
- Publisher
- Optica Publishing Group
- Language
- English
- Type
- Journal Article
- Abstract
- Digital holography numerically restores three-dimensional image information using optically captured diffractive waves. The required bandwidth is larger than that of hologram pixel at a closer distance in the Fresnel diffraction regime, which results in the formation of aliased replica patterns in digital hologram. From the analysis of sampling phenomenon, the replica functions are revealed to be the components of higher angular spectra of hologram. A undersampled hologram consists of the moire patterns formed by the modulation of original function by complex exponential function. There is a one-to-one correspondence between the replicas in both real and Fourier spaces. The acquisition methods of high-resolution images over a wide field view are proposed on the basis of the expansion process of angular spectrum by using replicas. Only the captured hologram with low numerical aperature or low resolution restores a high-resolution image when using an optimization algorithm. Numerical simulations and optical experiments are performed to investigate the proposed scheme.
- KSP Keywords
- Angular spectrum, Complex Exponential, Digital hologram, Expansion process, Fresnel diffraction, High resolution images, Holographic imaging, Image information, Numerical simulation(Trnsys16), One-to-one correspondence, Optimization algorithm