scholarly journals Occlusion culling for computer-generated cylindrical holograms based on a horizontal optical-path-limit function

2020 ◽  
Vol 28 (12) ◽  
pp. 18516
Author(s):  
Yuejia Li ◽  
Jun Wang ◽  
Chun Chen ◽  
Bingyi Li ◽  
Ruoxue Yang ◽  
...  
2018 ◽  
pp. 122-129
Author(s):  
Alexander T. Ovcharov ◽  
Yuri N. Selyanin ◽  
Yaroslav V. Antsupov

A new concept of the architecture of hybrid lighting systems for installations of combined lighting is considered. The cascade principle of constructing the optical path of such complexes is described, in which the design contains two stages of the cascade: the upper and lower stages. The upper (input) structure is made on the basis of the corresponding modification of the hollow tube “Solatube®” (daylight), and the lower one, based on the “Solatube®” fibre of a larger diameter, is combined with LED artificial light block and is designed to transmit mixed light (daylight and artificial light). The results of studies on the efficiency of light transmission made it possible to optimize the solution of the new modification of the hybrid lighting complex “Solar LED”, lower stage of the cascade, and to develop the nomenclature of the production line “S”. The description of the first experience of using this complex in the pilot combined illumination system of the “meeting room” in the shopping centre “IKEA Belaya Dacha” headquarters is given. A completely autonomous power supply system for a lighting installation based on solar panels has been implemented.


2000 ◽  
Vol 627 ◽  
Author(s):  
Gabriel Popescu ◽  
Aristide Dogariu

ABSTRACTIn many industrial applications involving granular media, knowledge about the structural transformations suffered during the industrial process is desirable. Optical techniques are noninvasive, fast, and versatile tools for monitoring such transformations. We have recently introduced optical path-length spectroscopy as a new technique for random media investigation. The principle of the method is to use a partially coherent source in a Michelson interferometer, where the fields from a reference mirror and the sample are combined to obtain an interference signal. When the system under investigation is a multiple-scattering medium, by tuning the optical length of the reference arm, the optical path-length probability density of light backscattered from the sample is obtained. This distribution carries information about the structural details of the medium. In the present paper, we apply the technique of optical path-length spectroscopy to investigate inhomogeneous distributions of particulate dielectrics such as ceramics and powders. The experiments are performed on suspensions of systems with different solid loads, as well as on powders and suspensions of particles with different sizes. We show that the methodology is highly sensitive to changes in volume concentration and particle size and, therefore, it can be successfully used for real-time monitoring. In addition, the technique is fiber optic-based and has all the advantages associated with the inherent versatility.


2012 ◽  
Vol E95.B (9) ◽  
pp. 2959-2963
Author(s):  
Yoshiyuki YAMADA ◽  
Hiroshi HASEGAWA ◽  
Ken-ichi SATO
Keyword(s):  

Author(s):  
Thierry Parrassin ◽  
Sylvain Dudit ◽  
Michel Vallet ◽  
Antoine Reverdy ◽  
Hervé Deslandes

Abstract By adding a transmission grating into the optical path of our photon emission system and after calibration, we have completed several failure analysis case studies. In some cases, additional information on the emission sites is provided, as well as understanding of the behavior of transistors that are associated to the fail site. The main application of the setup is used for finding and differentiating easily related emission spots without advance knowledge in light emission mechanisms in integrated circuits.


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 (1) ◽  
Author(s):  
L. Clermont ◽  
W. Uhring ◽  
M. Georges

AbstractUnderstanding stray light (SL) is a crucial aspect in the development of high-end optical instruments, for instance space telescopes. As it drives image quality, SL must be controlled by design and characterized experimentally. However, conventional SL characterization methods are limited as they do not provide information on its origins. The problem is complex due to the diversity of light interaction processes with surfaces, creating various SL contributors. Therefore, when SL level is higher than expected, it can be difficult to determine how to improve the system. We demonstrate a new approach, ultrafast time-of-flight SL characterization, where a pulsed laser source and a streak camera are used to record individually SL contributors which travel with a specific optical path length. Furthermore, the optical path length offers a means of identification to determine its origin. We demonstrate this method in an imaging system, measuring and identifying individual ghosts and scattering components. We then show how it can be used to reverse-engineer the instrument SL origins.


2021 ◽  
Vol 11 (15) ◽  
pp. 6742
Author(s):  
Hans Arwin ◽  
Stefan Schoeche ◽  
James Hilfiker ◽  
Mattias Hartveit ◽  
Kenneth Järrendahl ◽  
...  

Optical chirality, in terms of circular birefringence and circular dichroism, is described by its electromagnetic and magnetoelectric material tensors, and the corresponding optical activity contributes to the Mueller matrix. Here, spectroscopic ellipsometry in the spectral range 210–1690 nm is used to address chiral phenomena by measuring Mueller matrices in transmission. Three approaches to determine chirality parameters are discussed. In the first approach, applicable in the absence of linear polarization effects, circular birefringence and circular dichroism are evaluated directly from elements of a Mueller matrix. In the second method, differential decomposition is employed, which allows for the unique separation of chirality parameters from linear anisotropic parameters as well as from depolarization provided that the sample is homogeneous along the optical path. Finally, electromagnetic modeling using the Tellegen constitutive relations is presented. The last method also allows structural effects to be included. The three methods to quantify optical chirality are demonstrated for selected materials, including sugar solutions, α-quartz, liquid crystals, beetle cuticle, and films of cellulose nanocrystals.


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