A New Model of Solar Illumination of Earth’s Atmosphere during Night-Time

In this work, a solar illumination model of the Earth’s atmosphere is developed. The developed model allows us to determine with extreme accuracy how the atmospheric illumination varies during night hours on a global scale. This time-dependent variation in illumination causes a series of sudden changes in the entire Earth-atmosphere-ionosphere system of considerable interest for various research sectors and applications related to climate change, ionospheric disturbances, navigation and global positioning systems. The use of the proposed solar illumination model to calculate the time-dependent Solar Terminator Height (STH) at the global scale is also presented.Time-dependent STH impact on the measurements of ionospheric Total Electron Content (TEC) is, for the first time, investigated on the basis of 20 years long time series of GPS-based measurements collected at ground. The correlation analysis, performed in the post-sunset hours, allows new insights into the dependence of TEC–STH relation on the different periods (seasons) of observation and solar activity conditions.

Spatial function of light in staging of contemporary choreography

The principles of using light in choreographic performances are the basis of image perception integrity. The novelty of the study is determined by the fact that the illumination as a component of the performance can be based not only on the physical laws of light, but also on its imitation. To look into the matter of illumination, the authors consider it necessary to use a polygonal model, which can also form a spatial picture if necessary. The paper defines the general illumination model, which uses ray tracing technology and allows to determine the structure of lighting in the hall and to distribute the light to understand the director's intention among the entire visual sector. The practical significance of the study is determined by the structure of using lighting as part of staging choreography in the postmodern genre.

Modeling and realization for visual simulation of circular knitting transfer-jacquard fabric

The purpose of this research was to achieve visual simulation of circular weft-knitted transfer-jacquard fabric based on a computer-aided design platform. The corresponding mathematical models were established according to pattern presentations after analyzing the structural characteristics of this kind of stitch. To determine the spatial geometry of the loops, eight-point models were built, especially the introduced multi-course loop model. By comparing the influence of four usual lights on stereoscopic sense, directional light was selected to establish an illumination model. Based on these models and matrix operations, spatial positions of different loop types in the intermesh structure were confirmed by coordinate mapping. The simulation effects of three important parameters of yarn spline rendering were analyzed and discussed, so as to choose the most reasonable data. Integrated with a transfer-jacquard design program, the approach realized three-dimensional structural simulation of circular knitting transfer-jacquard fabric with a naturalistic visual impression which can shorten the proofing process and even inspire the design potential of developers.

Deep Light Direction Reconstruction from single RGB images

In augmented reality applications, consistent illumination between virtual and real objects is important for creating an immersive user experience. Consistent illumination can be achieved by appropriate parameterisation of the virtual illumination model, that is consistent with real-world lighting conditions. In this study, we developed a method to reconstruct the general light direction from red-green-blue (RGB) images of real-world scenes using a modified VGG-16 neural network. We reconstructed the general light direction as azimuth and elevation angles. To avoid inaccurate results caused by coordinate uncertainty occurring at steep elevation angles, we further introduced stereographically projected coordinates. Unlike recent deep-learning-based approaches for reconstructing the light source direction, our approach does not require depth information and thus does not rely on special red-green-blue- depth (RGB-D) images as input.

An Efficient and Lightweight Illumination Model for Planetary Bodies Including Direct and Diffuse Radiation

We present a numerical illumination model to calculate direct as well as diffuse or Hapke scattered radiation scenarios on arbitrary planetary surfaces. This includes small body surfaces such as main belt asteroids as well as e.g., the lunar surface. The model is based on the ray tracing method. This method is not restricted to spherical or ellipsoidal shapes but digital terrain data of arbitrary spatial resolution can be fed into the model. Solar radiation is the source of direct radiation, wavelength-dependent effects (e.g. albedo) can be accounted for. Mutual illumination of individual bodies in implemented (e.g. in binary or multiple systems) as well as self-illumination (e.g. crater floors by crater walls) by diffuse or Hapke radiation. The model is validated by statistical methods. A χ2 test is utilized to compare simulated images with DAWN images acquired during the survey phase at small body 4 Vesta and to successfully prove its validity.

An Efficient and Leightweight Illumination model for Planetary Bodies including Direct and Diffuse Radiation

We present a numerical illumination model to calculate direct as well as diffuse or Hapke scattered radiation scenarios on arbitrary planetary surfaces. This includes small body surfaces such as main belt asteroids as well as e.g. the lunar surface. The model is based on the raytracing method. This method is not restricted to spherical or ellipsiodal shapes but digital terrain data of arbitrary spatial resolution can be fed into the model. Solar radiation is the source of direct radiation, wavelength-dependent effects (e.g. albedo) can be accounted for. Mutual illumination of individual bodies in implemented (e.g. in binary or multiple systems) as well as self-illumination (e.g. crater floors by crater walls) by diffuse or Hapke radiation. The model is validated by statistical methods. A χ2 test is undertaken to compare simnulated images with DAWN images acquired during the survey phase at small body 4 Vesta.

Study on Hull Line Fairing Based on CATIA

Ship lofting is the first process of hull construction, which aims to smooth hull lines. In most shipyards of China, the hull line fairing work is completed on one platform HD-SHM. And the modelling is on the other platform CATIA. The data exchange process between different platforms is troublesome. In order to solve this problem, add-on development on CATIA by VBA is finished. With the offset data of the front half bow of a bulk carrier used as the initial data, the circle rate sequence mathematical algorithm is proposed to fair the single line. The errors of offsets were found and corresponding adjustment were taken. After all the hull lines were faired, a smooth hull surface was obtained finally. The powerful analysis functions of CATIA on curvature and on illumination model are applied to value the smoothness of the hull surface.