scholarly journals Scaling of Three-Dimensional Computer-Generated Holograms with Layer-Based Shifted Fresnel Diffraction

2019 ◽  
Vol 9 (10) ◽  
pp. 2118 ◽  
Author(s):  
Hao Zhang ◽  
Liangcai Cao ◽  
Guofan Jin
Keyword(s):  
Three Dimensional ◽  
Fresnel Diffraction ◽  
Depth Image ◽  
Depth Information ◽  
Display System ◽  
3D Images ◽  
Holographic Display ◽  
Computer Generated Holograms ◽  
3D Scene ◽  
Human Eyes

Holographic three-dimensional (3D) displays can reconstruct a whole wavefront of a 3D scene and provide rich depth information for the human eyes. Computer-generated holographic techniques offer an efficient way for reconstructing holograms without complicated interference recording systems. In this work, we present a technique for generating 3D computer-generated holograms (CGHs) with scalable samplings, by using layer-based diffraction calculations. The 3D scene is partitioned into multiple layers according to its depth image. Shifted Fresnel diffraction is used for calculating the wave diffractions from the partitioned layers to the CGH plane with adjustable sampling rates, while maintaining the depth information. The algorithm provides an effective method for scaling 3D CGHs without an optical zoom module in the holographic display system. Experiments have been performed, demonstrating that the proposed method can reconstruct quality 3D images at different scale factors.

scholarly journals Metalens Eyepiece for 3D Holographic Near-Eye Display

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1920
Author(s):  
Chang Wang ◽  
Zeqing Yu ◽  
Qiangbo Zhang ◽  
Yan Sun ◽  
Chenning Tao ◽  
...  
Keyword(s):  
Light Field ◽  
Three Dimensional ◽  
Fresnel Diffraction ◽  
Virtual Image ◽  
Display Devices ◽  
Computer Generated Holography ◽  
Wavefront Shaping ◽  
3D Scene ◽  
Optimum Solution ◽  
532 Nm

Near-eye display (NED) systems for virtual reality (VR) and augmented reality (AR) have been rapidly developing; however, the widespread use of VR/AR devices is hindered by the bulky refractive and diffractive elements in the complicated optical system as well as the visual discomfort caused by excessive binocular parallax and accommodation-convergence conflict. To address these problems, an NED system combining a 5 mm diameter metalens eyepiece and a three-dimensional (3D), computer-generated holography (CGH) based on Fresnel diffraction is proposed in this paper. Metalenses have been extensively studied for their extraordinary capabilities at wavefront shaping at a subwavelength scale, their ultrathin compactness, and their significant advantages over conventional lenses. Thus, the introduction of the metalens eyepiece is likely to reduce the issue of bulkiness in NED systems. Furthermore, CGH has typically been regarded as the optimum solution for 3D displays to overcome limitations of binocular systems, since it can restore the whole light field of the target 3D scene. Experiments are carried out for this design, where a 5 mm diameter metalens eyepiece composed of silicon nitride anisotropic nanofins is fabricated with diffraction efficiency and field of view for a 532 nm incidence of 15.7% and 31°, respectively. Furthermore, a novel partitioned Fresnel diffraction and resample method is applied to simulate the wave propagations needed to produce the hologram, with the metalens capable of transforming the reconstructed 3D image into a virtual image for the NED. Our work combining metalens and CGH may pave the way for portable optical display devices in the future.

scholarly journals Fusion Coding of 3D Real and Virtual Scenes Information for Augmented Reality-Based Holographic Stereogram

2021 ◽  
Vol 9 ◽  
Author(s):  
Yunpeng Liu ◽  
Xingpeng Yan ◽  
Xinlei Liu ◽  
Xi Wang ◽  
Tao Jing ◽  
...  
Keyword(s):  
Augmented Reality ◽  
Three Dimensional ◽  
Depth Map ◽  
Depth Information ◽  
Sampling System ◽  
The Real ◽  
Coding Method ◽  
Holographic Stereogram ◽  
3D Scene ◽  
Instance Segmentation

In this paper, an optical field coding method for the fusion of real and virtual scenes is proposed to implement an augmented reality (AR)-based holographic stereogram. The occlusion relationship between the real and virtual scenes is analyzed, and a fusion strategy based on instance segmentation and depth determination is proposed. A real three-dimensional (3D) scene sampling system is built, and the foreground contour of the sampled perspective image is extracted by the Mask R-CNN instance segmentation algorithm. The virtual 3D scene is rendered by a computer to obtain the virtual sampled images as well as their depth maps. According to the occlusion relation of the fusion scenes, the pseudo-depth map of the real scene is derived, and the fusion coding of 3D real and virtual scenes information is implemented by the depth information comparison. The optical experiment indicates that AR-based holographic stereogram fabricated by our coding method can reconstruct real and virtual fused 3D scenes with correct occlusion and depth cues on full parallax.

scholarly journals Rendering Distortion Estimation Model for 3D High Efficiency Depth Coding

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Qiuwen Zhang ◽  
Liang Tian ◽  
Lixun Huang ◽  
Xiaobing Wang ◽  
Haodong Zhu
Keyword(s):  
High Efficiency ◽  
Three Dimensional ◽  
Rate Distortion ◽  
Depth Map ◽  
Depth Image ◽  
High Efficiency Video Coding ◽  
Estimation Model ◽  
Depth Image Based Rendering ◽  
Distortion Estimation ◽  
3D Scene

A depth map represents three-dimensional (3D) scene geometry information and is used for depth image based rendering (DIBR) to synthesize arbitrary virtual views. Since the depth map is only used to synthesize virtual views and is not displayed directly, the depth map needs to be compressed in a certain way that can minimize distortions in the rendered views. In this paper, a modified distortion estimation model is proposed based on view rendering distortion instead of depth map distortion itself and can be applied to the high efficiency video coding (HEVC) rate distortion cost function process for rendering view quality optimization. Experimental results on various 3D video sequences show that the proposed algorithm provides about 31% BD-rate savings in comparison with HEVC simulcast and 1.3 dB BD-PSNR coding gain for the rendered view.

scholarly journals Holographic 3D Display Using Depth Maps Generated by 2D-to-3D Rendering Approach

2021 ◽  
Vol 11 (21) ◽  
pp. 9889
Author(s):  
Zehao He ◽  
Xiaomeng Sui ◽  
Liangcai Cao
Keyword(s):  
Depth Map ◽  
3D Display ◽  
Perspective View ◽  
Holographic Display ◽  
3D Rendering ◽  
Computer Generated Holograms ◽  
3D Effect ◽  
Human Eyes ◽  
3D Content ◽  
2D To 3D

Holographic display has the potential to be utilized in many 3D application scenarios because it provides all the depth cues that human eyes can perceive. However, the shortage of 3D content has limited the application of holographic 3D displays. To enrich 3D content for holographic display, a 2D to 3D rendering approach is presented. In this method, 2D images are firstly classified into three categories, including distant view images, perspective view images and close-up images. For each category, the computer-generated depth map (CGDM) is calculated using a corresponding gradient model. The resulting CGDMs are applied in a layer-based holographic algorithm to obtain computer-generated holograms (CGHs). The correctly reconstructed region of the image changes with the reconstruction distance, providing a natural 3D display effect. The realistic 3D effect makes the proposed approach can be applied in many applications, such as education, navigation, and health sciences in the future.

scholarly journals Augmented reality using holographic display

2017 ◽  
Vol 3 (1) ◽  
Author(s):  
Hung-Chun Lin ◽  
Yung-Hsun Wu
Keyword(s):  
Image Quality ◽  
Augmented Reality ◽  
Depth Information ◽  
Viewing Angle ◽  
Virtual Image ◽  
The Real ◽  
Holographic Display ◽  
Extra Information ◽  
Wide Viewing Angle ◽  
3D Scene

AbstractAugmented reality (AR) provided extra information to the user by applying virtual image onto the real environment. There are many methods achieving AR. Holographic display is one of the potential ways due to its perfect 3D demonstration. Holographic display can provide the virtual 3D object with depth information. It can be realized an AR device with real 3D scene by combing holographic display. However, it is difficult to realize a compact holographic display with wide viewing angle and enough resolution. It limits holographic display to apply to AR. In this paper, we will discuss the requirements of holographic display based on the development of LCD, including resolution (ppi), viewing angle, image quality and backlight. We wish this article can provide preliminary direction for the LCD industry to develop AR technology using holographic display.

scholarly journals Real-time three-dimensional video reconstruction of real scenes with deep depth using electro-holographic display system

2019 ◽  
Vol 27 (11) ◽  
pp. 15662 ◽  
Author(s):  
Hidenari Yanagihara ◽  
Takashi Kakue ◽  
Yota Yamamoto ◽  
Tomoyoshi Shimobaba ◽  
Tomoyoshi Ito
Keyword(s):  
Real Time ◽  
Three Dimensional ◽  
Display System ◽  
Holographic Display ◽  
Deep Depth ◽  
Video Reconstruction
Sign in / Sign up

Export Citation Format

Share Document