scholarly journals Image-based BRDF Representation

2015 ◽  
Vol 11 (2) ◽  
pp. 47-56
Author(s):  
A. Mihálik ◽  
R. Ďurikovič
Keyword(s):  
Mobile Phones ◽  
Scattered Light ◽  
Incident Light ◽  
Image Synthesis ◽  
Two Dimensional ◽  
Sample Material ◽  
Bidirectional Reflectance ◽  
Reflectance Function ◽  
Small Set ◽  
Realistic Image

Abstract To acquire a certain level of photorealism in computer graphics, it is necessary to analyze, how the materials scatter the incident light. In this work, we propose the method to direct rendering of isotropic bidirectional reflectance function (BRDF) from the small set of images. The image-based rendering is focused to synthesize as accurately as possible scenes composed of natural and artificial objects. The realistic image synthesis of BRDF data requires evaluation of radiance over the multiple directions of incident and scattered light from the surface. In our approach the images depict only the material reflectance, the shape is represented as the object geometry. We store the BRDF representation, acquired from the sample material, in a number of two-dimensional textures that contain images of spheres lit from the multiple directions. In order to render particular material, we interpolate between textures in the similar way the image morphing works. Our method allows the real-time rendering of tabulated BRDF data on low memory devices such as mobile phones.

scholarly journals Metallic paint appearance measurement and rendering

2013 ◽  
Vol 9 (2) ◽  
pp. 25-39 ◽  
Author(s):  
Andrej Mih´alik ◽  
Roman Ďurikovič
Keyword(s):  
Distribution Function ◽  
Spectral Reflectance ◽  
Incident Light ◽  
Image Synthesis ◽  
Measured Data ◽  
Optical Effect ◽  
Bidirectional Reflectance Distribution Function ◽  
Bidirectional Reflectance ◽  
Metallic Particles ◽  
Bidirectional Reflectance Distribution

Abstract Humans recognize objects visually on the basis of material composition as well as shape. To acquire a certain level of photorealism, it is necessary to analyze, how the materials scatter the incident light. The key quantity for expressing the directional optical effect of materials on the incident radiance is the bidirectional reflectance distribution function (BRDF). Our work is devoted to the BRDF measurements, in order to render the synthetic images, mostly of the metallic paints. We measured the spectral reflectance off multiple paint samples then used the measured data to fit the analytical BRDF model, in order to acquire its parameters. In this paper we describe the methodology of the image synthesis from measured data. Materials such as the metallic paints exhibit a sparkling effect caused by the metallic particles scattered within the paint volume. Our analysis of sparkling effect is based on the processing of the multiple photographs. Results of analysis and the measurements were incorporated into the rendering process of car paint

scholarly journals Rational Design and Simulation of Two-Dimensional Perovskite Photonic Crystal Absorption Layers Enabling Improved Light Absorption Efficiency for Solar Cells

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2460
Author(s):  
Jian Zou ◽  
Mengnan Liu ◽  
Shuyu Tan ◽  
Zhijie Bi ◽  
Yong Wan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solar Cells ◽  
Photonic Crystal ◽  
Incident Light ◽  
Absorption Efficiency ◽  
Utilization Efficiency ◽  
Photonic Crystal Structure ◽  
Two Dimensional ◽  
Photoelectric Conversion ◽  
Absorption Layer

A two-dimensional perovskite photonic crystal structure of Methylamine lead iodide (CH3NH3PbI3, MAPbI3) is rationally designed as the absorption layer for solar cells. The photonic crystal (PC) structure possesses the distinct “slow light” and band gap effect, leading to the increased absorption efficiency of the absorption layer, and thus the increased photoelectric conversion efficiency of the battery. Simulation results indicate that the best absorption efficiency can be achieved when the scattering element of indium arsenide (InAs) cylinder is arranged in the absorption layer in the form of tetragonal lattice with the height of 0.6 μm, the diameter of 0.24 μm, and the lattice constant of 0.4 μm. In the wide wavelength range of 400–1200 nm, the absorption efficiency can be reached up to 82.5%, which is 70.1% higher than that of the absorption layer without the photonic crystal structure. In addition, the absorption layer with photonic crystal structure has good adaptability to the incident light angle, presenting the stable absorption efficiency of 80% in the wide incident range of 0–80°. The results demonstrate that the absorption layer with photonic crystal structure can realize the wide spectrum, wide angle, and high absorption of incident light, resulting in the increased utilization efficiency of solar energy.

Realistic image synthesis of outer space targets and environment based on database management

2009 ◽  
Author(s):  
Changbo Wang ◽  
Zhuopeng Zhang ◽  
Hongyan Quan ◽  
Zhangye Wang ◽  
Lin Wei
Keyword(s):  
Database Management ◽  
Outer Space ◽  
Image Synthesis ◽  
Realistic Image

scholarly journals Novel Two-Dimensional Layered MoSi2Z4 (Z = P, As): New Promising Optoelectronic Materials

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 559
Author(s):  
Hui Yao ◽  
Chao Zhang ◽  
Qiang Wang ◽  
Jianwei Li ◽  
Yunjin Yu ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Incident Light ◽  
Optoelectronic Devices ◽  
Large Family ◽  
Middle Layer ◽  
Optoelectronic Device ◽  
First Principles Calculation ◽  
Polarization Angle ◽  
Two Dimensional ◽  
Conducting Materials

Very recently, two new two-dimensional (2D) layered semi-conducting materials MoSi2N4 and WSi2N4 were successfully synthesized in experiments, and a large family of these two 2D materials, namely MA2Z4, was also predicted theoretically (Science, 369, 670 (2020)). Motivated by this exciting family, in this work, we systematically investigate the mechanical, electronic and optical properties of monolayer and bilayer MoSi2P4 and MoSi2As4 by using the first-principles calculation method. Numerical results indicate that both monolayer and bilayer MoSi2Z4 (Z = P, As) present good structural stability, isotropic mechanical parameters, moderate bandgap, favorable carrier mobilities, remarkable optical absorption, superior photon responsivity and external quantum efficiency. Especially, due to the wave-functions of band edges dominated by d orbital of the middle-layer Mo atoms are screened effectively, the bandgap and optical absorption hardly depend on the number of layers, providing an added convenience in the experimental fabrication of few-layer MoSi2Z4-based electronic and optoelectronic devices. We also build a monolayer MoSi2Z4-based 2D optoelectronic device, and quantitatively evaluate the photocurrent as a function of energy and polarization angle of the incident light. Our investigation verifies the excellent performance of a few-layer MoSi2Z4 and expands their potential application in nanoscale electronic and optoelectronic devices.

Adaptive Sampling Based on GH-Distance for Realistic Image Synthesis

2014 ◽  
Vol 998-999 ◽  
pp. 806-813
Author(s):  
Jian Wang ◽  
Qing Xu
Keyword(s):  
Monte Carlo ◽  
Computer Graphics ◽  
Adaptive Sampling ◽  
Random Noise ◽  
Image Synthesis ◽  
Simulation Methods ◽  
Path Tracing ◽  
Complex Scenes ◽  
Realistic Image ◽  
Better Than

Realistic image synthesis technology is an important part in computer graphics. Monte Carlo based light simulation methods, such as Monte Carlo path tracing, can deal with complex lighting computations for complex scenes, in the field of realistic image synthesis. Unfortunately, if the samples taken for each pixel are not enough, the generated images have a lot of random noise. Adaptive sampling is attractive to reduce image noise. This paper proposes a new GH-distance based adaptive sampling algorithm. Experimental results show that the method can perform better than other similar ones.

Absorption and Emission of Light in Quantum Structures

2020 ◽  
pp. 343-418
Author(s):  
Vurgaftman Igor
Keyword(s):  
Quantum Wells ◽  
Radiative Recombination ◽  
Quantum Wires ◽  
Incident Light ◽  
Optical Gain ◽  
Two Dimensional ◽  
Intersubband Transitions ◽  
Recombination Rates ◽  
Zinc Blende ◽  
Two Dimensional Materials

This chapter shows how to calculate the absorption coefficient, optical gain, and radiative recombination rates in quantum wells and superlattices. A detailed treatment of both interband and intersubband transitions is presented, and their differences and similarities are considered in detail. The optical properties of wurtzite quantum wells and zinc-blende quantum wires and dots are also discussed. Finally, the interaction of excitonic transitions with incident light in quantum wells is considered as a model for other two-dimensional materials.

scholarly journals NoRM: No-Reference Image Quality Metric for Realistic Image Synthesis

2012 ◽  
Vol 31 (2pt3) ◽  
pp. 545-554 ◽  
Author(s):  
Robert Herzog ◽  
Martin Čadík ◽  
Tunç O. Aydčin ◽  
Kwang In Kim ◽  
Karol Myszkowski ◽  
...  
Keyword(s):  
Image Quality ◽  
Image Synthesis ◽  
Reference Image ◽  
Quality Metric ◽  
Image Quality Metric ◽  
Realistic Image
Sign in / Sign up

Export Citation Format

Share Document