Holographic Stereogram Research Articles

From Text to Hologram: Creation of High-Quality Holographic Stereograms Using Artificial Intelligence

This study simplified the creation of holographic stereograms using AI-generated prompts, overcoming the conventional need for complex equipment and professional software. AI enabled the generation of detailed perspective images suitable for various content styles. The generated images were interpolated, upscaled, and printed using a CHIMERA holoprinter to obtain high-quality holograms. This method significantly reduces the required time and expertise, thereby making holographic content creation accessible. This approach demonstrated that AI can effectively streamline the production of high-fidelity holograms, suggesting exciting future advancements in holographic technology.

Outdoor Content Creation for Holographic Stereograms with iPhone

Outdoor Content Creation for Holographic Stereograms with iPhone

Radiance-field holography for high-quality 3D reconstruction

Conventional light field-based computer-generated holograms, such as holographic stereograms, can provide nature parallax and accurate occlusion relation but are restricted by the inherent tradeoff concerning the angular and spatial resolution of the reconstructed optical field. In contrast, Wigner distribution function based light field generated holograms, also called non-hogel-based holograms, release this limitation by using basic ray-to-wave transformation frameworks. However, at present, this transformation framework is accurate only for generating holograms from orthogonal light field images of 3D scenes with a limited depth range and size. Thus, the radiance field holography method is proposed in this paper to generate high-quality 3D holograms for arbitrary scenes that can achieve high-resolution reconstruction within a deep depth range. In our method, a proposed radiance field is constructed from the perspective light field, which consists of multiple reference planes to resample and redistribute the light rays to represent the diffracted optical field of the 3D objects according to our developed sampling criterion. The complex optical field of the 3D object can be synthesized from these reference planes based on inverse Wigner transform and Fresnel propagation. As a result, both the numerical simulations and the optical experiments are implemented, and it is demonstrated that the high-quality 3D reconstruction of the synthesized hologram is achieved, which reflects the highest reconstruction resolution among the existing methods, the large depth range with accurate refocus and defocus, and the natural view-dependent effects.

Holographic Stereogram: from Printing to Computing (Invited)

Holographic Stereogram: from Printing to Computing (Invited)

Light Field Acquisition Using Shack-Hartmann Wavefront Sensor and Its Application to Holographic Stereogram

Light Field Acquisition Using Shack-Hartmann Wavefront Sensor and Its Application to Holographic Stereogram

Recording of Full-Color Snapshot Digital Holographic Portraits Using Neural Network Image Interpolation

For 60 years, high-energy pulsed lasers have enabled the recording of extremely realistic portraits of living people within a few nanoseconds. In the 21st century, this confidential technique, which requires great skill and equipment, has almost disappeared because of the final monochromatic color of the holograms, which does not appeal to the public. In this study, we show that ultra-realistic, full-color, and full-parallax snapshot holographic portraits can be recorded using a limited number of synchronized HD cameras. Experiments were successfully conducted using the digital CHIMERA holographic stereogram printing technique combined with image interpolation using a neural network. This new recording method allows holographic portraits to be developed and disseminated to the public on a larger scale.

Dynamic holographic stereogram using temporal and perspective coherence

A dynamic holographic stereogram (HS) rendering technique using temporal and perspective (TP) coherence is proposed and demonstrated. It solves the issue that previous holographic rendering methods are difficult to record HS of time-varying three-dimensional (3D) images efficiently. In our technique, a unified mathematical model is set in EPIpolar coordinates for the generation of light field images of dynamic HS. The time dimension is encoded in angular coordinates through angular multiplexing. Temporal coherence of dynamic 3D images is applied to simplify the rendering of action key frames. The action key frames are the same as conventional key frames, but have 3D information. Perspective coherence is used to render the light field images between two adjacent action key frames. Parallel computing technology combined with TP coherence is used to accelerate the rendering, which is on average 378.8% faster than traditional serial per-viewpoint rendering (PVR) algorithms. HSs with vivid and striking 3D animations are demonstrated using a custom holographic printing system, which validates the effectiveness of the proposed method. The results pave the way towards developing high-performance dynamic HSs that can be used in 3D display, visual security, and virtual/augmented reality domain.

Depth-map-based augmented reality holographic stereogram: Method and verification

In this paper, a perspective image fusion algorithm of real-world and artificial scenes based on depth maps is proposed and applied to holographic printing to realize augmented reality display of holographic stereograms. The basic principle of the fusion algorithm is introduced, and the perspective image fusion with correct occlusion relation is implemented theoretically. Under the condition of sampling only once, an image generation algorithm with adjustable depth of artificial scenes is proposed and implemented. We use effective perspective image segmentation and mosaicking method for optical experiments, and verify the effectiveness of the proposed method.

Azo-carbazole copolymer-based composite films with high optical transparency for updatable holograms

The poly(CACzE-MMA)/CACzE composite film plasticized with DPP showed remarkable holographic properties and transparency, which repeatedly and clearly reconstructed holographic stereograms and transmitted volume holograms.

Holostereosynthesis: An Improvement to Louis Lumière’s Photostereosynthesis Technique

In 1920, Louis Lumière, one of the fathers of Cinématograph, invented photostereosynthesis, a photography technique that could recreate three-dimensional images without a specific artifice. This method involved stacking six to eight photographs of the same subject, usually a portrait, recorded with a progressive shift in focus and observed together through transparency. This invention remained at the laboratory experiment stage, and only a dozen portraits of famous people from the time of Lumière are known. The final device is a complex assembly of glass plates mounted on a wooden frame, and it is fragile, bulky, heavy, and difficult to build and observe. Here, we demonstrate that we can replace the stack of photographic plates with a single reflection hologram. Experiments were successfully conducted using the digital CHIMERA holographic stereogram printing technique. This new method of holostereosynthesis will facilitate the restoration and dissemination of the historical portraits originally recorded by Louis Lumière and may also allow the creation of brand new images.

Resolution-improved holographic stereogram for dual-view 3D display based on integral imaging

In this paper, a dual-view 3D display using a holographic stereogram based on integral imaging was proposed and implemented without the use of complex components. To improve the quality of the reconstructed 3D images, we developed a modified holographic stereogram utilizing resolution-priority integral imaging. A resolution-improved dual-view 3D display was achieved by converting plane-wave propagation to spherical-wave propagation during image reconstruction. We compared reconstructed images from the identical viewpoint of the above proposed methods with corresponding reference images by numerical simulations and optical experiments. Both simulated and experimental results confirmed that using the modified holographic stereogram for dual-view 3D display effectively enhances resolution.

Accommodation and Vergence Responses to Electronic Holographic Displays and Super Multiview Holographic Stereograms

Electronic holography is an ideal 3-D display technique to ameliorate the vergence-accommodation conflict, which is a possible cause of visual fatigue and discomfort from viewing conventional stereoscopic 3-D displays. Previous studies have measured accommodative and vergence responses to holographic images and to real objects, and the results showed that these responses are in good agreement. To demonstrate the effectiveness of electronic holography as a possible solution to the vergence-accommodation conflict caused by viewing conventional stereoscopic 3-D displays, we measured both accommodative and vergence responses to reconstructed images of holograms and super multiview holographic stereograms. We also measured responses to real objects located at various distances and conventional two-view stereo images for comparison. The results indicate that the accommodative responses to the electro-holographic display and super multiview holographic stereogram change with the vergence response in a similar manner, as is the case with real objects as compared to conventional two-view stereo display. This suggests that the electronic holographic display and super multiview holographic stereograms are promising candidates for resolving the vergence-accommodation conflict.

Hogel-Free Holography

Holography is a promising avenue for high-quality displays without requiring bulky, complex optical systems. While recent work has demonstrated accurate hologram generation of 2D scenes, high-quality holographic projections of 3D scenes has been out of reach until now. Existing multiplane 3D holography approaches fail to model wavefronts in the presence of partial occlusion while holographic stereogram methods have to make a fundamental tradeoff between spatial and angular resolution. In addition, existing 3D holographic display methods rely on heuristic encoding of complex amplitude into phase-only pixels which results in holograms with severe artifacts. Fundamental limitations of the input representation, wavefront modeling, and optimization methods prohibit artifact-free 3D holographic projections in today’s displays. To lift these limitations, we introduce hogel-free holography which optimizes for true 3D holograms, supporting both depth- and view-dependent effects for the first time. Our approach overcomes the fundamental spatio-angular resolution tradeoff typical to stereogram approaches. Moreover, it avoids heuristic encoding schemes to achieve high image fidelity over a 3D volume. We validate that the proposed method achieves 10 dB PSNR improvement on simulated holographic reconstructions. We also validate our approach on an experimental prototype with accurate parallax and depth focus effects.

P‐7.8: Characteristic analysis on special‐shaped pupil of holographic stereogram

In this paper, the light field regulation characteristics of the size and transmittance function of hogel in holographic stereogram are analyzed, which shows that the display quality of holographic stereogram can be effectively improved by using special-shaped pupil. The limitation of hogel size in optimizing the light field regulation characteristics of holographic stereogram is analyzed from the perspective of resolution and view-flipping effect. By establishing the diffraction limited imaging model with aberration in holographic stereogram, the point spread function (PSF) characterizing the image point propagation characteristics is obtained, and the important variable affecting image point propagation, that is, the type of pupil function, is further found. The quantitative comparison of various functions shows that the special-shaped pupil will have better performance. Simulation experiments further verify the theoretical analysis.

Perspective clipping and fast rendering of light field images for holographic stereograms using RGBD data.

The production of holographic stereogram (HS) requires a huge amount of light field data. How to efficiently clip and render these image data remains a challenge in the field. This work focuses on the perspective clipping and fast rendering algorithm for light field images using RGBD data without explicit 3D reconstruction. The RGBD data is expanded to RGBDθ data by introducing a light cone for each point, which gives a new degree of freedom for light field image rendering. Using the light cone and perspective coherence, the visibility of 3D image points can be clipped programmatically. Optical imaging effects including mirror imaging and half mirror imaging effects of 3D images can also be rendered with the help of light cones during the light field rendering process. The perspective coherence is also used to accelerate the rendering, which has been shown to be on average 168% faster than traditional DIBR algorithms. A homemade holographic printing system was developed to make the HSs using the rendered light field images. The vivid 3D effects of the HS have validated the effectiveness of the proposed method. It can also be used in holographic dynamic 3D display, augmented reality, virtual reality, and other fields.

Inverse-Directed Propagation-Based Hexagonal Hogel Sampling for Holographic Stereogram Printing System

Holographic stereogram (HS) printing is a promising holographic technique for three-dimensional (3D) visualization of an object with accurate depth cues. In this paper, unlike the conventional rectangular hogel based HS, efficient hexagonal hogels sampling for HS printing that enhances the volumetric visualization of reconstruction while providing rapidly generated data using inverse-directed propagation (IDP) is proposed. Specifically, an array of hexagonal hogels is sampled by a computer-generated integral imaging technique using an IDP, which acquires the full information of the 3D object prior to higher volumetric 3D reconstruction. To demonstrate the proposed approach, IDP-based hexagonal hogel sampling for HS printing is implemented, and the enhanced image quality of printed holograms is verified both by numerical simulation and in an optical experiment.

Computer generated color rainbow holographic stereogram

In this research, a fast method to calculate the color rainbow holographic stereogram (CRHS) by taking full advantage of the sparsity of the frequency domain is demonstrated. The CRHS is a novel color rainbow hologram containing a large number of elemental CRHSs, where each elemental CRHS only reproduces the color light field information of local 3D color object. The color of the reconstructed color 3D image perceived by the human eye is determined by the spectrum of the reproduced dispersion of different elemental CRHSs that enter the human eye. The calculation of the CRHS is implemented with parallel computing by inversely Fourier transforming the frequency of each elemental CRHS. With the proposed method, the computation time for a resolution of 200k × 200k pixels and size of 64 × 64 mm CRHS is only 15.4 min for a color 3D model with 406k object points. The optical reconstruction with a white LED light illumination proves the effectiveness of our proposed method, which can be applied to the field of color holographic 3D display, advertising or holographic packaging.

Wide-viewing holographic stereogram based on self-interference incoherent digital holography.

We propose a holographic stereogram synthesis method which uses holograms that are optically captured by self-interference incoherent digital holography (SIDH) based on a geometric phase lens. SIDH is a promising solution for hologram acquisition under low-coherence lighting condition. A mechanical scanning system is constructed to acquire multiple perspective holograms. Numerical simulations and experimental analyses conducted using high-resolution diffractive optical element demonstrate that the proposed method can produce a wide-viewing hologram which can realize realistic 3D scenarios with depth cues such as accommodation and motion parallax. The future objectives include the implementation of a multiple-camera system for holographic videos.

Holobricks: modular coarse integral holographic displays

Here, we propose and demonstrate a modular holographic display system that allows seamless spatial tiling of multiple coarse integral holographic (CIH) displays called “holobricks”. A holobrick is a self-contained CIH module enclosing a spatial light modulator (SLM), a scanner, and periscopic coarse integral optics. Modular CIH uses a coarse pitch and small area but high-bandwidth SLM in conjunction with periscopic coarse integral optics to form the angularly tiled 3D holograms with large viewing areas and fields of view. The creation of periscopic coarse integral optics prevents the optical system from being larger than the holographic image and allows the holographic fringe pattern to fill the entire face of the holobrick. Thus, multiple holobricks can be seamlessly abutted to form a scalable spatially tiled holographic image display capable of both wide field-of-view angle and arbitrary large-size area. We demonstrate an initial prototype that seamlessly tiles two holobricks each with 1024 × 768 pixels, 40° FOV, full color, 24 fps, displaying 2D, 3D holographic stereograms, and full parallax 3D CGI Fresnel holograms.

Accelerated Generation of a Pinhole-Type Holographic Stereogram Based on Human Eye Characteristics in Near-Eye Displays

In near-eye displays (NEDs), issues such as weight, heat, and power consumption mean that the rendering and computing power is usually insufficient. Due to this limitation, algorithms need to be further improved for the rapid generation of holograms. In this paper, we propose two methods based on the characteristics of the human eye in NEDs to accelerate the generation of the pinhole-type holographic stereogram (HS). In the first method, we consider the relatively fixed position of the human eye in NEDs. The number of visible pixels from each elemental image is very small due to the limited pupil size of an observing eye, and the calculated amount can be dramatically reduced. In the second method, the foveated region rendering method is adopted to further enhance the calculation speed. When the two methods are adopted at the same time, the calculation speed can be increased dozens of times. Simulations demonstrate that the proposed method can obviously enhance the generation speed of a pinhole-type HS.