scholarly journals Demonstration of light reflection concepts for rendering realistic 3D tree images

2021 ◽  
Vol 2145 (1) ◽  
pp. 012074
Author(s):  
Tiantada Hiranyachattada ◽  
Kampanat Kusirirat ◽  
Kasem Kamolchaipisit ◽  
Panadda Jaiboonlue
Keyword(s):  
Computer Graphics ◽  
Diffuse Reflection ◽  
Specular Reflection ◽  
Normal Direction ◽  
Natural Images ◽  
Light Reflection ◽  
Image Rendering ◽  
Surface Normal ◽  
Realistic Images ◽  
Natural Complexity

Abstract With advancements in computer graphics, creating natural images has always been the main purpose, image rendering is all based on principles of physics. So, understanding the physics of image rendering will enable us to create the most realistic images. A ray of light hit a surface with different orientation and reflects as per the rules of physics. It is difficult to calculate the light reflection of complex foliage, such as trees, so, the reflection of this natural complexity needs to be adapted to rendering situations. In this research, the researchers provide demonstrations to enable students to understand the light reflection in nature, light calculation in computer graphics and methods to apply them to render realistic tree images. The researchers assign students to render 3D realistic tree images to assess the students’ understanding by applying the diffuse reflection value, specular reflection value and surface normal direction to render realistic tree images. The researchers find that most students understand of diffuse reflection, specular reflection, and surface normal direction causes the rendering results to be most realistic.

Structural characterization of laser ablated epitaxial (Ba0.5Sr0.5)TiO3 thin films on MgO(001) by synchrotron x-ray scattering

1999 ◽  
Vol 14 (7) ◽  
pp. 2905-2911 ◽  
Author(s):  
Sangsub Kim ◽  
Tae Soo Kang ◽  
Jung Ho Je
Keyword(s):  
Thin Films ◽  
Early Stage ◽  
Lattice Parameter ◽  
Normal Direction ◽  
X Ray ◽  
X Ray Scattering ◽  
Surface Normal ◽  
Out Of Plane ◽  
Axis Parallel ◽  
Ray Scattering

Epitaxial (Ba0.5Sr0.5) TiO3 thin films of two different thickness (∼25 and ∼134 nm) on MgO(001) prepared by a pulsed laser deposition method were studied by synchrotron x-ray scattering measurements. The film grew initially with a cube-on-cube relationship, maintaining it during further growth. As the film grew, the surface of the film became significantly rougher, but the interface between the film and the substrate did not. In the early stage of growth, the film was highly strained in a tetragonal structure (c/a = 1.04) with the longer axis parallel to the surface normal direction. As the growth proceeded further, it relaxed to a cubic structure with the lattice parameter near the bulk value, and the mosaic distribution improved significantly in both in- and out-of-plane directions. The thinner film (∼25 nm) showed only one domain limited mainly by the film thickness, but the thicker film (∼134 nm) exhibited three domains along the surface normal direction.

Fabry-Perot Velocimetry Techniques: Is Doppler Shift Affected By Surface Normal Direction?

1984 ◽  
Author(s):  
David R. Goosman ◽  
Alan M. Frank, ◽  
Henry H. Chau ◽  
Norval L. Parker
Keyword(s):  
Doppler Shift ◽  
Normal Direction ◽  
Surface Normal ◽  
Fabry Perot

scholarly journals Microspectroscopic infrared specular reflection chemical imaging of multi-component urinary stones: MIR vs. FIR

2014 ◽  
Vol 12 (1) ◽  
pp. 44-52 ◽  
Author(s):  
Milda Pucetaite ◽  
Sandra Tamosaityte ◽  
Anders Engdahl ◽  
Justinas Ceponkus ◽  
Valdas Sablinskas ◽  
...  
Keyword(s):  
Diffuse Reflection ◽  
Specular Reflection ◽  
Far Infrared ◽  
Chemical Imaging ◽  
Urinary Stones ◽  
High Contrast ◽  
Mid Infrared ◽  
Infrared Microspectroscopy ◽  
Spectral Bands ◽  
Far Infrared Radiation

AbstractSpecular reflection infrared microspectroscopy was used for chemical imaging of cross-sectioned urinary stones to determine their chemical composition and morphology simultaneously. Absorption spectral bands were recovered from reflection spectra by Kramers-Kronig transform. FUse of far-infrared radiation provides high-contrast images and allows more precise constituent distribution determinations than mid-infrared because band asymmetry after the transform caused by diffuse reflection is less in the far-infrared.

Investigation of the Two-Bar Warp-Knitted Fabric Structure Effect on Luster Value

2014 ◽  
Vol 9 (2) ◽  
pp. 155892501400900
Author(s):  
Saeed Ajeli ◽  
Zoleykhah Ahmadvand
Keyword(s):  
Diffuse Reflection ◽  
Specular Reflection ◽  
Knitted Fabric ◽  
Knitted Fabrics ◽  
Fabric Structure ◽  
Measuring Surface ◽  
Before And After ◽  
Dark Color ◽  
Points Of View ◽  
Warp Knitted Fabric

Consumer points of view determine economical value of fabrics. Fabric luster plays a momentous role in attracting people's attention, especially for clothing and domestic purposes. Luster is defined by intensity of both specular and diffuse light reflection off of a surface. There are various methods for measuring surface luster. Gloss. Luster is described as the ratio of specular reflection in one angle to diffuse reflection in another angle. Two-bar warp knitted polyester fabrics such as Tricot, Locknit, Satin, reverse Locknit and Sharkskin in three different densities were provided. A mini gloss apparatus was applied to measure fabric specular reflection in the angle of sixty degrees, before and after disperse dying with different colors of white, blue and yellow. Results suggest that luster is a function of knitted fabric type, color and density. Enhancement of technical back luster resulted from longer underlap of the front bar. However, it did not change the technical face luster significantly. Density increased in all knitted fabrics and caused the luster to decrease. Dark color fabrics showed lower luster compared to light ones.

A New Image Irradiance Equation for Perspective Shape from Shading of Hybrid Surfaces

2014 ◽  
Vol 519-520 ◽  
pp. 676-679
Author(s):  
Guo Hui Wang ◽  
Jin Cheng ◽  
Quan Rui Wei
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Diffuse Reflection ◽  
Specular Reflection ◽  
Linear Partial Differential Equation ◽  
Shape From Shading ◽  
Point Light Source ◽  
Imaging Model ◽  
Reflectance Model ◽  
Point Light

Shape from shading (SFS) is a classical and important problem in the domain of computer vision. This paper presents a new image irradiance equation for perspective SFS method to reconstruct the hybrid surfaces that have both diffuse reflection and specular reflection. The hybrid reflectance model composed of a linear combination of Oren-Nayar model and Ward model is used to express the hybrid surfaces. An imaging model incorporating near point light source, perspective camera projection and the hybrid reflectance model is established. Under this model, the image irradiance equation has been derived as a non-linear partial differential equation (PDE). The resulting PDE is associated with a static Hamilton-Jacobi (H-J) equation considering the boundary conditions. Thus, the image irradiance equation of hybrid surfaces can be solved further.

Effects of Sample Dilution and Particle Size/Morphology on Diffuse Reflection Spectra of Carbohydrate Systems in the Near- and Mid-Infrared. Part II: Durum Wheat

1993 ◽  
Vol 47 (6) ◽  
pp. 695-701 ◽  
Author(s):  
Jill M. Olinger ◽  
Peter R. Griffiths
Keyword(s):  
Particle Size ◽  
Durum Wheat ◽  
Near Infrared ◽  
Diffuse Reflection ◽  
Specular Reflection ◽  
Analytical Data ◽  
Reflection Spectra ◽  
Depth Of Penetration ◽  
Mid Infrared ◽  
Effective Depth

It is shown that reduction of particle size for ground durum wheat does not cause a concomitant decrease in the amount of specular reflection observed in the mid-infrared spectrum of the neat sample. Specular reflection can be reduced, but not completely eliminated, by dilution of the wheat in a nonabsorbing matrix such as KCl. The lack of dependence of mid-infrared diffuse reflection spectra of neat ground durum wheat on particle size is explained by the morphology of the surface of each particle and the low effective depth of penetration of mid-infrared radiation into particles of very high absorptivity. It is concluded that mid-infrared diffuse reflection spectra of wheats do not provide information characteristic of the overall composition of the wheat when the particle size exceeds a few micrometers, but that near-infrared diffuse reflection spectra will provide representative analytical data even when the particle size is large.

ESTIMATING FACIAL ALBEDO FROM A SINGLE IMAGE

2006 ◽  
Vol 20 (06) ◽  
pp. 955-970 ◽  
Author(s):  
WILLIAM A. P. SMITH ◽  
EDWIN R. HANCOCK
Keyword(s):  
Statistical Model ◽  
Normal Direction ◽  
Reconstructed Image ◽  
Intensity Data ◽  
Single Image ◽  
Image Brightness ◽  
Image Intensity ◽  
Surface Normal

This paper describes how a facial albedo map can be recovered from a single image using a statistical model that captures variations in surface normal direction. We fit the model to intensity data using constraints on the surface normal direction provided by Lambert's law and then use the differences between observed and reconstructed image brightness to estimate the albedo. We show that this process is stable under varying illumination. We then show how eigenfaces trained on albedo maps may provide a better representation for illumination insensitive recognition than those trained on raw image intensity.

Development of a System to Measure the Optical Properties of Facial Skin using a 3D Camera and Projector

2021 ◽  
Author(s):  
Kumiko Kikuchi ◽  
Shoji Tominaga ◽  
Jon Y. Hardeberg
Keyword(s):  
Optical Properties ◽  
Diffuse Reflection ◽  
Specular Reflection ◽  
Three Dimensional ◽  
Depth Image ◽  
Facial Skin ◽  
Subsurface Scattering ◽  
Surface Reflection ◽  
Reflection Model ◽  
Reflection Component

We have developed a system to measure both the optical properties of facial skin and the three-dimensional shape of the face. To measure the three-dimensional facial shape, our system uses a light-field camera to provide a focused image and a depth image simultaneously. The light source uses a projector that produces a high-frequency binary illumination pattern to separate the subsurface scattering and surface reflections from the facial skin. Using a dichromatic reflection model, the surface reflection image of the skin can be separated further into a specular reflection component and a diffuse reflection component. Verification using physically controlled objects showed that the separation of the optical properties by the system correlated with the subsurface scattering, specular reflection, or diffuse reflection characteristics of each object. The method presented here opens new possibilities in cosmetology and skin pharmacology for measurement of the skin’s gloss and absorption kinetics and the pharmacodynamics of various external agents.

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