scholarly journals Fast 3D Content Update for Wide-Angle Holographic Near-Eye Display

2021 ◽  
Vol 12 (1) ◽  
pp. 293
Author(s):  
Rafał Kukołowicz ◽  
Maksymilian Chlipala ◽  
Juan Martinez-Carranza ◽  
Moncy Sajeev Idicula ◽  
Tomasz Kozacki

Near-eye holographic displays are the holy grail of wear-on 3D display devices because they are intended to project realistic wide-angle virtual scenes with parameters matching human vision. One of the key features of a realistic perspective is the ability to move freely around the virtual scene. This can be achieved by addressing the display with wide-angle computer-generated holograms (CGHs) that enable continuous viewpoint change. However, to the best of our knowledge there is no technique able to generate these types of content. Thus, in this work we propose an accurate and non-paraxial hologram update method for wide-angle CGHs that supports continuous viewpoint change around the scene. This method is based on the assumption that with a small change in perspective, two consecutive holograms share overlapping data. This enables reusing the corresponding part of the information from the previous view, eliminating the need to generate an entirely new hologram. Holographic information for the next viewpoint is calculated in two steps: first, a tool approximating the Angular Spectrum Propagation is proposed to generate the hologram data from previous viewpoint; and second, the efficient Phase Added Stereogram algorithm is utilized for generating the missing hologram content. This methodology offers fast and accurate calculations at the same time. Numerical and optical experiments are carried out to support the results of the proposed method.

Photonics ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 298
Author(s):  
Juan Martinez-Carranza ◽  
Tomasz Kozacki ◽  
Rafał Kukołowicz ◽  
Maksymilian Chlipala ◽  
Moncy Sajeev Idicula

A computer-generated hologram (CGH) allows synthetizing view of 3D scene of real or virtual objects. Additionally, CGH with wide-angle view offers the possibility of having a 3D experience for large objects. An important feature to consider in the calculation of CGHs is occlusion between surfaces because it provides correct perception of encoded 3D scenes. Although there is a vast family of occlusion culling algorithms, none of these, at the best of our knowledge, consider occlusion when calculating CGHs with wide-angle view. For that reason, in this work we propose an occlusion culling algorithm for wide-angle CGHs that uses the Fourier-type phase added stereogram (PAS). It is shown that segmentation properties of the PAS can be used for setting efficient conditions for occlusion culling of hidden areas. The method is efficient because it enables processing of dense cloud of points. The investigated case has 24 million of point sources. Moreover, quality of the occluded wide-angle CGHs is tested by two propagation methods. The first propagation technique quantifies quality of point reproduction of calculated CGH, while the second method enables the quality assessment of the occlusion culling operation over an object of complex shape. Finally, the applicability of proposed occlusion PAS algorithm is tested by synthetizing wide-angle CGHs that are numerically and optically reconstructed.


2021 ◽  
Vol 11 (16) ◽  
pp. 7199
Author(s):  
Dapu Pi ◽  
Juan Liu

In this article, we propose a reference light wave multiplexing scheme to increase the information capacity of computer-generated holograms. The holograms were generated by different reference light waves and superimposed together as a multiplexed hologram. A modified Gerchberg–Saxton algorithm was used to improve image quality, and different images could be reconstructed when the multiplexed hologram was illuminated by corresponding reference light waves. We performed both numerical simulations and optical experiments to demonstrate the feasibility of the proposed scheme. Numerical simulations showed that the proposed method could reconstruct multiple images successfully by a single multiplexed hologram and optical experiments are consistently good with numerical simulations. It is expected that the proposed method has great potential to be widely applied in holographic displays in the future.


Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1358
Author(s):  
Taihui Wu ◽  
Jianshe Ma ◽  
Chengchen Wang ◽  
Haibei Wang ◽  
Liangcai Cao ◽  
...  

An optical encryption method based on computer generated holograms printing of photopolymer is presented. Fraunhofer diffraction is performed based on the Gerchberg-Saxton algorithm, and a hologram of the Advanced Encryption Standard encrypted Quick Response code is generated to record the ciphertext. The holograms of the key and the three-dimensional image are generated by the angular spectrum diffraction algorithm. The experimental results show that large-size encrypted Quick Response (QR) code and miniature keys can be printed in photopolymers, which has good application prospects in optical encryption. This method has the advantages of high-density storage, high speed, large fault tolerance, and anti-peeping.


Author(s):  
D. Fattal ◽  
Z. Peng ◽  
T. Tran ◽  
S. Vo ◽  
M. Fiorentino ◽  
...  
Keyword(s):  

2021 ◽  
Vol 41 (5) ◽  
pp. 0531001
Author(s):  
付秀华 Fu Xiuhua ◽  
郭宇怀 Guo Yuhuai ◽  
李爽 Li Shuang ◽  
张静 Zhang Jing ◽  
孙宇勃 Sun Yubo

2014 ◽  
Vol 596 ◽  
pp. 442-445
Author(s):  
Chang Long Jing ◽  
Qi Bin Feng ◽  
Ying Song Zhang ◽  
Guang Lei Yang ◽  
Zhi Gang Song ◽  
...  

A solid-state volumetric true 3D display developed by Hefei University of Technology consists of two main components: a high-speed video projector and a stack of liquid crystal shutters. The shutters are based on polymer stabilized cholesteric texture material, presenting different states that can be switched by different voltage. The high-speed video projector includes LED-based light source and tree-chip digital micro-mirror devices modulating RGB lights. A sequence of slices of three-dimensional images are projected into the liquid crystal shutters locating at the proper depth, forming a true 3D image depending on the human vision persistence. The prototype is developed. The measurement results show that the screen brightness can reach 149 nit and no flickers can be perceived.


2015 ◽  
Author(s):  
Weronika Zaperty ◽  
Malgorzata Kujawinska ◽  
Tomasz Kozacki ◽  
Bartosz Wisniowski
Keyword(s):  

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