A modeling method for virtual scene based on multi-view image sequence

Through the analysis and comparison of shortcomings and advantages of existing technologies on object modeling in 3D applications,we propose a new modeling method for virtual scene based on multi-view image sequence to model irregular objects efficiently in 3D application.In 3D scene,this method can get better visual effect by tracking the viewer's real-time perspective position and projecting the photos from different perspectives dynamically.The philosophy of design,the steps of development and some other relevant topics are discussed in details,and the validity of the algorithm is analyzed.The results demonstrate that this method represents more superiority on simulating irregular objects by applying it to the modeling of virtual museum.

Construction of Virtual Turning Scene Based on Local Ray Tracing Algorithm

According to the features of the turning simulation, a simplified Whitted lighti ng model is proposed based on the analysis of Phong and other local illumination model. Moreover, in order to obtain the natural lighting effects, local ray tra cing algorithm is given to calculate the light intensity of every position durin g the course of the simulation. This method can calculate the refresh area befor e calculating the intersection line, simulate the machining environment accurate ly and reduce the calculating time. Finally, an example of the virtual cutting s cene is shown to demonstrate the effects of the global illumination model. If th e CUP is 1.3 G and the internal memory is 128 M, the refreshing time of virtual turning scene can be reduced by nine times.This study plays an important role in the enrichment of the virtual manufacturing theory and the promotion of the dev elopment of the advanced manufacturing technology.

Digital Simulation Platform for Satellite Launch Mission Verification

To simulate the satellite launch mission under a general platform which could be used in a full-digital mode as well as in a semi-physical way, is an important way to certify the mission design performance as well as technical feasibilities, and it relates to complex system simulation methods such as multi-disciplinary coupling, multi-language modeling as well as interactive simulation and virtual simulation technologies. This paper introduces the design of a digital simulation platform for satellite launch mission verification.The platform has the advantages of high generality and extensibility, being easy to build up. The Functional Mockup Interface(FMI) Standard is adopted to achieve integration of multi-source models. A WebGL based 3D visual simulation tool is also adopted to implement the virtual display system which could display the rocket launch process and rocket-satellite separation with high fidelity 3D virtual scenes. A configuration tool was developed to map the 3D objects in the visual scene with simulation physical variables for complex rocket flight control mechanisms, which greatly improves the platform's generality and extensibility. Finally the real-time performance had been tested and the YL-1 launch mission was adopted to demonstrate the functions of the platform.The platform will be used to construct a digital twin system for satellite launch missions in the future.

Courtrooms Could Host Virtual Crime Scenes

随着科技的发达,现在侦破犯罪的途径越来越先进。法庭声学及计算机合成的有关犯罪现场及犯罪过程的生动图像等就可以作为律师、法官对犯罪现场进行模拟从而有效破案的途径之一。

Ocean image data augmentation in the USV virtual training scene

The rapid development of intelligent navigation drives the rapid accumulation of ocean data,and the ocean science has entered the era of big data.However,the complexity and variability of the ocean environments make some data unavailable.It makes ocean target detection and the unmanned surface vehicle(USV)intelligent control process in ocean scenarios face various challenges,such as the lack of training data and training environment.Traditional ocean image data collection method used to capture images of complex ocean environments is costly,and it leads to a serious shortage of ocean scene image data.In addition,the construction of an autonomous learning environment is crucial but time-consuming.In order to solve the above problems,we propose a data collection method using virtual ocean scenes and the USV intelligent training process.Based on virtual ocean scenes,we obtain rare images of ocean scenes under complex weather conditions and implement the USV intelligent control training process.Experimental results show that the accuracy of ocean target detection and the success rate of obstacle avoidance of the USV are improved based on the virtual ocean scenes.

A Survey on 360°Images and Videos in Mixed Reality:Algorithms and Applications

Mixed reality technologies provide real-time and immersive experiences,which bring tremendous opportunities in entertainment,education,and enriched experiences that are not directly accessible owing to safety or cost.The research in this field has been in the spotlight in the last few years as the metaverse went viral.The recently emerging omnidirectional video streams,i.e.,360°videos,provide an affordable way to capture and present dynamic real-world scenes.In the last decade,fueled by the rapid development of artificial intelligence and computational photography technologies,the research interests in mixed reality systems using 360°videos with richer and more realistic experiences are dramatically increased to unlock the true potential of the metaverse.In this survey,we cover recent research aimed at addressing the above issues in the 360°image and video processing technologies and applications for mixed reality.The survey summarizes the contributions of the recent research and describes potential future research directions about 360°media in the field of mixed reality.

Automatic global path generation for large-scale 3D scene exploration

Large-scale virtual scene exploration is still a challenging task. The novice users caneasily get distracted and disorientated, which results in being lost in space. Assistedcamera control technology is the most effective solution for virtual environment exploration problems which requires viewpoint computation and path planning. In this paper,a novel approach for large-scale virtual scene based on viewpoint scoring is proposed.First, the scene was adaptively divided into several meaningful and easily analyzedsubregions according to the optimal view distance criterion. Second, a novel viewpointscoring method based on visual perception and information entropy fusion was developed for optimal viewpoint determination and greedy N-Best viewpoint selection algorithm was utilized for visual perceptibility calculation. Then evolutionary programmingapproach for the Traveling Salesman problem was applied for intra-subregion and intersubregion exploring path optimization. Finally, the Cubic Hermite Curve was introduced to smoothen the inflection point on the exploration path. The experimental resultsdemonstrate that the proposed method can effectively generate an automatic smooth,informative, aesthetic and non-intersecting path, with the characteristics of good exploring comfort, strong immersion and high scene information perception.

Comparison of Color and Grayscale Simulated TV-Graphics in Rendezvous and Docking

Subjective evaluation is one of the most important methods of assessing the fidelity of a virtual dynamic scene,whose results could be seen as a reference to improve a rendering method.In the present study,we apply a rendering method to the color rendezvous and docking(RVD) scene,where one shadow algorithm and three tone mapping operator algorithms are used to process the scene based on the distance between two spacecrafts.The grayscale RVD scene is transformed from the color RVD scene,and each RVD scene is desired to make comparisons with the real RVD-video recorded in SZ-10 mission.In addition,we perform an evaluation on 36 subjects to compare the results.The results show that shadow effects have important roles in RVD virtual scenes,where they enhance the sense of realism and immersion.Shadows,high brightness,contrast and luminance are highly correlated with the overall preference,and the grayscale scene receives better evaluations than the color scene.The analysis of these conclusions is vital for improving the algorithms used to render color virtual space scenes when virtual scenes for astronaut training in Chinese space station mission are prepared.