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2022 ◽  
Vol 41 (1) ◽  
pp. 1-15
Shilin Zhu ◽  
Zexiang Xu ◽  
Tiancheng Sun ◽  
Alexandr Kuznetsov ◽  
Mark Meyer ◽  

Although Monte Carlo path tracing is a simple and effective algorithm to synthesize photo-realistic images, it is often very slow to converge to noise-free results when involving complex global illumination. One of the most successful variance-reduction techniques is path guiding, which can learn better distributions for importance sampling to reduce pixel noise. However, previous methods require a large number of path samples to achieve reliable path guiding. We present a novel neural path guiding approach that can reconstruct high-quality sampling distributions for path guiding from a sparse set of samples, using an offline trained neural network. We leverage photons traced from light sources as the primary input for sampling density reconstruction, which is effective for challenging scenes with strong global illumination. To fully make use of our deep neural network, we partition the scene space into an adaptive hierarchical grid, in which we apply our network to reconstruct high-quality sampling distributions for any local region in the scene. This allows for effective path guiding for arbitrary path bounce at any location in path tracing. We demonstrate that our photon-driven neural path guiding approach can generalize to diverse testing scenes, often achieving better rendering results than previous path guiding approaches and opening up interesting future directions.

2022 ◽  
Vol 578 ◽  
pp. 121362
Zongliang Xiao ◽  
Baohui Zhang ◽  
Jianhang Li ◽  
Haozhang Liang ◽  
Zhiwei Luo ◽  

Ichha Yadav

Abstract: Cheque is one of the most important and commonly encountered financial documents by many individuals and banks for various financial transactions all over the world. Thus, the security and integrity of the cheque is the acute need. Different kind of security features are embedded in bank cheques in order to prevent fraud and counterfeiting of cheques and other bank security documents. Security features appended are in two different ways covert and overt features, some of which are watermarks, logo, serial number, A/c number etc. which can be viewed under different light sources and instruments for examination. In this study the embedded security features of Indian Bank Cheque are examined under instrument Docucenter Nirvis. After examination, deriving to the conclusion that the Indian bank note is appended with ample security features. Keywords: cheque, security features, embedded, examination, counterfeiting

Mansi Kadam

Abstract: In today’s era of illuminating devices, there are a wide variety of devices available in aesthetics but the none with variable intensity of light. Using the basic principle of polarization of light using a Polaroid filter or polarizer, the designing of a light intensity control was done. The polarizing angle of the filter decides the intensity of the light that would pass through the filters. According to the principle of propagation of light, the electric and magnetic vibrations of a light wave occur perpendicularly to each other. A light wave that is vibrating in more than one plane is known as unpolarized light. The light emitted by the sun, by a lamp or a tube light are all unpolarized light sources. The other kind of wave is a polarized wave. A Plane polarized light vibrates on only one plane. The process of transforming unpolarized light into the polarized light is known as polarization. Using the same principle and with the use of a LDR (light dependent resister) as a sensor to sense the intensity of the surrounding light and then rotate the polaroid filter sheets accordingly using a stepper motor for the required change in intensity. The sensing and sending of feedback and subsequent rotation of the Polaroid filter sheets would be automated by ATMEGA32 microcontroller and L293D. Keywords: Polaroids, LDR, Light Variation, ATMEGA32, L293D

Solar ◽  
2022 ◽  
Vol 2 (1) ◽  
pp. 1-11
Johanna Zikulnig ◽  
Wolfgang Mühleisen ◽  
Pieter Jan Bolt ◽  
Marcel Simor ◽  
Martin De Biasio

Renewable energy sources such as photovoltaic (PV) technologies are considered to be key drivers towards climate neutrality. Thin-film PVs, and particularly copper indium gallium selenide (CIGS) technologies, will play a crucial role in the turnaround in energy policy due to their high efficiencies, high product flexibility, light weight, easy installation, lower labour-intensiveness, and lower carbon footprint when compared to silicon solar cells. Nonetheless, challenges regarding the CIGS fabrication process such as moderate reproducibility and process tolerance are still hindering a broad market penetration. Therefore, cost-efficient and easily implementable in-line process control methods are demanded that allow for identification and elimination of non-conformal cells at an early production step. As part of this work, a practical approach towards industrial in-line photoluminescence (PL) imaging as a contact-free quality inspection tool is presented. Performance parameters of 10 CIGS samples with 32 individually contacted cells each were correlated with results from PL imaging using green and red excitation light sources. The data analysis was fully automated using Python-based image processing, object detection, and non-linear regression modelling. Using the red excitation light source, the presented PL imaging and data processing approach allows for a quantitative assessment of the cell performance.

Harry Jay Levinson

Abstract High-NA extreme ultraviolet (EUV) lithography is currently in development. Fabrication of exposure tools and optics with a numerical aperture (NA) equal to 0.55 has started at ASML and Carl Zeiss. Lenses with such high NA will have very small depths-of-focus, which will require improved focus systems and significant improvements in wafer flatness during processing. Lenses are anamorphic to address mask 3D issues, which results in wafer field sizes of 26 mm × 16.5 mm, half that of lower NA EUV tools and optical scanners. Production of large die will require stitching. Computational infrastructure is being created to support high-NA lithography, including simulators that use Tatian polynomials to characterize the aberrations of lenses with central obscurations. High resolution resists that meet the line-edge roughness (LER) and defect requirements for high-volume manufacturing (HVM) also need to be developed. High power light sources will also be needed to limit photon shot noise.

2022 ◽  
Vol 13 (1) ◽  
P. K. Singh ◽  
F.-Y. Li ◽  
C.-K. Huang ◽  
A. Moreau ◽  
R. Hollinger ◽  

AbstractIntense lasers can accelerate electrons to very high energy over a short distance. Such compact accelerators have several potential applications including fast ignition, high energy physics, and radiography. Among the various schemes of laser-based electron acceleration, vacuum laser acceleration has the merits of super-high acceleration gradient and great simplicity. Yet its realization has been difficult because injecting free electrons into the fast-oscillating laser field is not trivial. Here we demonstrate free-electron injection and subsequent vacuum laser acceleration of electrons up to 20 MeV using the relativistic transparency effect. When a high-contrast intense laser drives a thin solid foil, electrons from the dense opaque plasma are first accelerated to near-light speed by the standing laser wave in front of the solid foil and subsequently injected into the transmitted laser field as the opaque plasma becomes relativistically transparent. It is possible to further optimize the electron injection/acceleration by manipulating the laser polarization, incident angle, and temporal pulse shaping. Our result also sheds light on the fundamental relativistic transparency process, crucial for producing secondary particle and light sources.

2022 ◽  
Vol 12 (1) ◽  
Marta Hornyák ◽  
Michał Dziurka ◽  
Monika Kula-Maximenko ◽  
Jakub Pastuszak ◽  
Anna Szczerba ◽  

AbstractLight-emitting diodes (LEDs) and high-pressure sodium lamps (HPS) are among the most commonly used light sources for plant cultivation. The objective of this study was to evaluate the effect of two controlled-environment production systems differing in light sources on growth, photosynthetic activity, and secondary metabolism of common buckwheat. We hypothesized that LED light with the majority of red and blue waves would increase physiological and biochemical parameters compared to sunlight supplemented with HPS lamps. The experiment was performed in a phytotronic chamber (LEDs) and in a greenhouse (solar radiation supplemented with HPS lamps as a control). The effects were analyzed at the flowering phase with biometric measurements, leaf chlorophyll index, the kinetics of chlorophyll a fluorescence, content of soluble carbohydrates and phenolics in the leaves. Applied LED light decreased the biomass but stimulated the production of phenolics compared to control plants. In control plants, a positive correlation between flavonoid content and energy dissipation from photosystem II (DIo/CSm) was found, while in plants under LEDs total pool of phenolic content correlated with this parameter and the quantum yield of electron transport (φ Ro and ψ Ro) was lower than that of the control, probably affecting buckwheat biomass.

PeerJ ◽  
2022 ◽  
Vol 9 ◽  
pp. e12684
Hansheng Li ◽  
Yuqiang Qiu ◽  
Gang Sun ◽  
Wei Ye

Dendrobium officinale Kimura et Migo (D. officinale) has promising lung moisturizing, detoxifying, and immune boosting properties. Light is an important factor influencing functional metabolite synthesis in D. officinale. The mechanisms by which lasers affect plants are different from those of ordinary light sources; lasers can effectively address the shortcomings of ordinary light sources and have significant interactions with plants. Different light treatments (white, blue, blue laser) were applied, and the number of red leaves under blue laser was greater than that under blue and white light. RNA-seq technology was used to analyze differences in D. officinale under different light treatments. The results showed 465, 2,107 and 1,453 differentially expressed genes (DEGs) in LB-B, LB-W and W-B, respectively. GO, KEGG and other analyses of DEGs indicated that D. officinale has multiple blue laser response modes. Among them, the plasma membrane, cutin, suberine and wax biosynthesis, flavone and flavonol biosynthesis, heat shock proteins, etc. play central roles. Physiological and biochemical results verified that blue laser irradiation significantly increases POD, SOD, and PAL activities in D. officinale. The functional metabolite results showed that blue laser had the greatest promoting effect on total flavonoids, polysaccharides, and alkaloids. qPCR verification combined with other results suggested that CRY DASH, SPA1, HY5, and PIF4 in the blue laser signal transduction pathway affect functional metabolite accumulation in D. officinale through positively regulated expression patterns, while CO16 and MYC2 exhibit negatively regulated expression patterns. These findings provide new ideas for the efficient production of metabolites in D. officinale.

2022 ◽  
pp. 31-40

Purpose. Substantiation and creation of automatic lighting control in interactive rooms using piezoelectric converters. The introduction of this technology will significantly reduce energy consumption during the operation of such premises. The addition of further technological solutions based on the use of phosphor coatings and ultraviolet lighting will create a full range of innovative methods of child interaction in the social space.Methodology. The combination of piezo sensors with design elements such as "live" tiles as a trigger mechanism will create the necessary connection between the physical activity of the child and the regulation of light. The modern level of development and complete safety of materials such as phosphors in combination with specially designed point light sources will make it possible to create additional lighting and a field for the imagination of the child. Since the main attention when lighting children's rooms should be directed to the safe stay of the child, the use of light sources under a translucent floor will solve safety issues with a low level of energy consumption.Findings. An experimental study of the methods has proven the feasibility of using the proposed elements for any interactive children's room. The low cost of both equipment and the energy efficiency of all the technologies used is a significant advantage of this project over other developments with a large use of digital gadgets. The ability of create light of different spectral composition and color temperature is analyzed by using color filters and special light sources.Originality. The technologies and techniques presented in this work will be used for the first time to create interactive activities for a child. Separately, each technological solution was applied individually. This project combines separate developments to create a single interactive and light space. A low level of electricity consumption is achieved by using specially designed piezoelectric elements. Replacing standard ceiling lighting with lower (floor) lighting allows you to achieve the desired illumination using luminaires of lower power.Practical value. Recently, it has been proven that digitalization has a negative impact on the emotional state of the child and the only solution to replace it is to switch the child's attention to other more physically active actions. The proposed solutions in the work will allow their to be involved in group trainings. At the same time, the power consumption for obtaining such rooms will be much lower than the rest of the existing ones. The simplicity of the equipment and the possibility of variation during the operation of the premises make it available for creation in any institution of education, medicine, sports, etc.

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