Holography


Digital Holography

  • Optical scanning holography

In optical scanning holography, one pupil produces a spherical wave and the other produces a plane wave. They interfere with each other and result in a fringe pattern for scanning a three-dimensional object and produce the hologram.

Published papers:

– Ni Chen, Zhenbo Ren, Haiyan Ou, and Edmund Y. Lam, “Resolution enhancement of optical scanning holography with a modulated point spread function,” Photonics Research, 4(1):1–6, 2016.

Zhenbo Ren, Ni Chen, and Edmund Y. Lam, “Extended focused imaging and depth map reconstruction in optical scanning holography,” Applied Optics 55(5):1040–1047, 2016.

  • Phase-shifting holography

  Implement of conventional phase shifting holography.
 Matlab Code:

 


Synthesized Hologram

  • Synthesized Hologram based on Integral Imaging

3D objects are captured through a lens array, the captured elemental images are processed to orthographic images, which are used to eynthesize the hologram. The resolution of the reconstructed images are limited by the lens array, therefore we analysized the parameters that affect the hologram resolution, compared the resolution of the hologram reconstructions with different shape lens arrays, and proposed lens array shift method to enhance the resolution of the reconstructed images.

Published papers:

– Ni Chen, Jiwoon Yeom, Jae-Hyun Jung, Jae-Hyeung Park, and Byoungho Lee, “Resolution comparison between integral–imaging–based hologram synthesis methods using rectangular and hexagonal lens arrays,” Optics Express 19(27):26917–26927, 2011.

– Ni Chen, Jae-Hyeung Park, and Nam Kim, “Parameter analysis of integral Fourier hologram and its resolution enhancement,” Optics Express 18(3):2152–2167, 2010.

  • Synthesized Hologram from photographic images

We obtain a hight-resolution digital hologram with the light field obtained from a series of photographic images captured along the optical axis.

Published papers:

– Ni Chen∗, Zhenbo Ren, and Edmund Y. Lam∗, “High resolution Fourier hologram synthesis from photographic images through computing the light field,” Applied Optics 55(7):1751–1756, 2016.


 

Hologram encoding

  • Phase-only encoding

Double Phase

The typical phase encoding techniques for holograms are implemented and compared.

1.  Kinoform;

2. Double phase;

3. Checkerboard Encoding

Matlab Code:
  • Amplitude-only encoding

Detour Phase

The typical amplitude encoding techniques for holograms are implemented and compared.

1. Reference amp;

2. LohmanIII;

3. Detour-Phase

Matlab Code:

 

  • Phase and amplitude encoding

The typical complex encoding of holograms techniques are implemented and compared.

1, ROACH;

Matlab Code:

 

 



Colorful hologram reconstruction

  • Division-based techniques

fun_holo-color Several division based colorful hologram reconstruction techniques are studied and compared.

1. depth division;

2. space division;

3. space division inline;

4. space division phase only

Matlab Code:

 

 


Auto-focusing