Hologram generation via Hilbert transform

Author(s):

Tomoyoshi Shimobaba, Takashi Kakue, Yota Yamamoto, Ikuo Hoshi, Harutaka Shiomi, Takashi Nishitsuji, Naoki Takada, and Tomoyoshi Ito

Abstract:

“We propose an indirect method for generating a complex hologram and phase-only hologram from an amplitude hologram using the Hilbert transform. The Hilbert transform generates an imaginary part of complex amplitude from only an amplitude hologram, resulting in the reduction of the total computational complexity of complex and phase-only holograms. More importantly, the proposed method can reduce the hardware resources of dedicated hologram processors.”

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Publication: OSA Continuum
Issue/Year/DOI: Vol. 3, Issue 6, pp. 1498-1503 (2020)
DOI: 10.1364/OSAC.395003

Non-iterative phase hologram generation with optimized phase modulation

Author(s):

Lizhi Chen, Hao Zhang, Liangcai Cao and Guofan Jin

Abstract:

“A non-iterative algorithm is proposed to generate phase holograms with optimized phase modulation. A quadratic initial phase with continuous distributed spectrum is utilized to iteratively optimize the phase modulation in the reconstruction plane, which can be used as an optimized phase distribution for arbitrary target images. The phase hologram can be calculated directly according to the modulated wave field distribution in the reconstruction plane. Fast generation of the phase holograms can be achieved by this non-iterative implementation, and the avoidance of the random phase modulation helps to suppress the speckle noise. Numerical and
optical experiments have demonstrated that the proposed method can efficiently generate phase holograms with quality reconstructions.”

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Publication: Optics Express

Issue/Year/DOI: Vol. 28, Issue 8, pp. 11380-11392
DOI: 10.1364/OE.391518

Three-Dimensional Holographic Reconstruction of Brain Tissue Based on Convolution Propagation

Author(s):

Rania M. Abdelazeem and Doaa Youssef and Jala El-Azab and Salah Hassab-Elnaby and Mostafa Agour

Abstract:

” In this study, a dynamic holographic projection system for brain tissue and its anatomical structures extracted from Magnetic Resonance (MR) plane slice is reported. Computer holograms are calculated using a modied Gerchberg-Saxton (GS) iterative algorithm where the projection is based on the plane wave decomposition. First, brain anatomy includes white matter (WM), grey matter (GM) and brain tissue are extracted. Then, phase holograms using the proposed method are generated. Finally, single phase hologram for the whole brain anatomy is generated and is optically reconstructed by a phase-only spatial light modulator (SLM) at dierent depths. The obtained results revealed that the three-dimensional holographic projection of MR brain tissue can aid to provide better interpretation of brain anatomical
structure to achieve better diagnostic results.”

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Publication: Journal of Physics: Conference Series
Issue/Year/DOI: Vol. 1472
DOI: 10.1088/1742-6596/1472/1/012008

Holographic near-eye display with continuously expanded eyebox using two-dimensional replication and angular spectrum wrapping

Author(s):

Myeong-Ho Choi, Yeon-Gyeong Ju and Jae-Hyeung Park

Abstract:

“Holographic near-eye displays present true three-dimensional images with full
monocular depth cues. In this paper, we propose a technique to expand the eyebox of the
holographic near-eye displays. The base eyebox of the holographic near-eye displays is determined
by the space bandwidth product of a spatial light modulator. The proposed technique replicates
and stitches the base eyebox by the combined use of a holographic optical element and high order
diffractions of the spatial light modulator, achieving horizontally and vertically expanded eyebox.
An angular spectrum wrapping technique is also applied to alleviate image distortions observed
at the boundaries between the replicated base eyeboxes.”

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Publication: Optics Express

Issue/Year/DOI: Vol. 28, Issue 1, pp. 533-547
DOI: 10.1364/OE.381277

Optical see-through holographic near-eye-display with eyebox steering and depth of field control

Author(s):
Jae-Hyeung Park and Seong-Bok Kim

Abstract:

“We propose an optical see-through holographic near-eye-display that can control the depth of field of individual virtual three-dimensional image and replicate the eyebox with dynamic steering. For optical see-through capability and eyebox duplication, a holographic optical element is used as an optical combiner where it functions as multiplexed tilted concave mirrors forming multiple copies of the eyebox. Fo1r depth of field control and eyebox steering, computer generated holograms of three-dimensional objects are synthesized with different ranges of angular spectrum. In optical experiment, it has been confirmed that the proposed system can present always-focused images with large depth of field and three-dimensional images at different distances with shallow depth of field at the same time without any time-multiplexing.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express Volume 26, Issue 21
DOI: 10.1364/oe.26.027076

Accelerated generation of holographic videos of 3-D objects in rotational motion using a curved hologram-based rotational-motion compensation method

Author(s):

Hong-Kun Cao and Shu-Feng Lin and Eun-Soo KimAbstract:

“Abstract: A new curved hologram-based rotational-motion compensation (CH-RMC) method is proposed for accelerated generation of holographic videos of 3-D objects moving on the random path with many locally different arcs. All of those rotational motions of the object made on each arc can be compensated, just by rotating their local curved holograms along the curving surfaces matched with the object’s moving trajectory without any additional calculation process, which results in great enhancements of the computational speed of the conventional hologram-generation algorithms. Experiments with a test video scenario reveal that average numbers of calculated object points (ANCOPs) and average calculation times for one frame (ACTs) of the CH-RMC-based ray-tracing, wavefront-recording-plane and novel- look-up-table methods have been found to be reduced by 73.10%, 73.84%, 73.34%, and 68.75%, 50.82%, 66.59%, respectively, in comparison with those of their original methods. In addition, successful reconstructions of 3-D scenes from those holographic videos confirm the feasibility of the proposed system. ”

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Publication: Optics Express
Issue/Year/DOI: Optics Express Volume 26, Issue 16 pp. 21279-21300 (2018)
DOI: 10.1364/oe.26.021279

Reduction of speckle noise in laser energy distribution on the target by means of modified Fourier hologram and incoherent averaging technique

Author(s):

A.G. Derzhypolskyi, O.V. Gnatovskyi and L.A. Derzhypolska

Abstract:

“Presented in this paper is the technique of formation of required laser intensity distribution on the target with a reduced speckle noise. The method is based on the use of modified Fourier hologram adapted to controlled phase modulators. Reduction of the speckle noise in the laser energy profile is obtained using multiple incoherent superposition of synthesized holographic images. Each hologram is synthesized with different random diffuser. The advantages of this method: relative simplicity of hardware; robustness with regard to distortions of any kind in input beam and/or optical path of the scheme; controlled
reduction of the speckle noise in the final energy distribution. ”

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Publication: Semiconductor Physics, Quantum Electronics and Optoelectronics

Issue/Year/DOI: Volume: 21 (4), P. 429-433 (2018).
DOI: 10.15407/spqeo21.04.429

Holographic near-eye display system based on double-convergence light Gerchberg-Saxton algorithm

Author(s):

Peng Sun and Shengqian Chang and Siqi Liu and Xiao Tao and Chang Wang and Zhenrong Zheng

Abstract:

“In this paper, a method is proposed to implement noises reduced three-dimensional (3D) holographic near-eye display by phase-only computer-generated hologram (CGH). The CGH is calculated from a double-convergence light Gerchberg-Saxton (GS) algorithm, in which the phases of two virtual convergence lights are introduced into GS algorithm simultaneously. The first phase of convergence light is a replacement of random phase as the iterative initial value and the second phase of convergence light will modulate the phase distribution calculated by GS algorithm. Both simulations and experiments are carried out to verify the feasibility of the proposed method. The results indicate that this method can effectively reduce the noises in the reconstruction. Field of view (FOV) of the reconstructed image reaches 40 degrees and experimental light path in the 4-f system is shortened. As for 3D experiments, the results demonstrate that the proposed algorithm can present 3D images with 180cm zooming range and continuous depth cues. This method may provide a promising solution in future 3D augmented reality (AR) realization.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express, Vol. 26, Issue 8, pp. 10140- 10151 (2018)
DOI: 10.1364/OE.26.010140

Interactive Holographic Display Based on Finger Gestures.

Author(s):

Yamada, Shota and Kakue, Takashi and Shimobaba, Tomoyoshi and Ito, Tomoyoshi

Abstract:

“In this paper, we demonstrate an interactive, finger-sensitive system which enables an observer to intuitively handle electro-holographic images in real time. In this system, a motion sensor detects finger gestures (swiping and pinching) and translates them into the rotation and enlargement/reduction of the holographic image, respectively. By parallelising the hologram calculation using a graphics processing unit, we realised the interactive handling of the holographic image in real time. In a demonstration of the system, we used a Leap Motion sensor and a phase modulation-type spatial light modulator with 1,920 × 1,080 pixels and a pixel pitch of 8.0 µm × 8.0 µm. The constructed interactive finger-sensitive system was able to rotate a holographic image composed of 4,096 point light sources using a swiping gesture and enlarge or reduce it using a pinching gesture in real time. The average calculation speed was 27.6 ms per hologram. Finally, we extended the constructed system to a full-colour reconstruction system that generates a more realistic three-dimensional image. The extended system successfully allowed the handling of a full-colour holographic image composed of 1,709 point light sources with a calculation speed of 22.6 ms per hologram.”

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Publication: Scientific Reports

Issue/Year/DOI: Scientific Reportsvolume 8, Article number: 2010 (2018)
DOI: 10.1038/s41598-018-20454-6

Real-time colour hologram generation based on ray-sampling plane with multi-GPU acceleration.

Author(s):

Sato, Hirochika and Kakue, Takashi and Ichihashi, Yasuyuki and Endo, Yutaka and Wakunami, Koki and Oi, Ryutaro and Yamamoto, Kenji and Nakayama, Hirotaka and Shimobaba, Tomoyoshi and Ito, Tomoyoshi

Abstract:

“Although electro-holography can reconstruct three-dimensional (3D) motion pictures, its computational cost is too heavy to allow for real-time reconstruction of 3D motion pictures. This study explores accelerating colour hologram generation using light-ray information on a ray-sampling (RS) plane with a graphics processing unit (GPU) to realise a real-time holographic display system. We refer to an image corresponding to light-ray information as an RS image. Colour holograms were generated from three RS images with resolutions of 2,048 × 2,048; 3,072 × 3,072 and 4,096 × 4,096 pixels. The computational results indicate that the generation of the colour holograms using multiple GPUs (NVIDIA Geforce GTX 1080) was approximately 300-500 times faster than those generated using a central processing unit. In addition, the results demonstrate that 3D motion pictures were successfully reconstructed from RS images of 3,072 × 3,072 pixels at approximately 15 frames per second using an electro-holographic reconstruction system in which colour holograms were generated from RS images in real time.”

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Publication: Scientific Reports

Issue/Year/DOI:  Scientific Reports Volume 8, Article number: 1500 (2018)
DOI: 10.1038/s41598-018-19361-7

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