With technological advancements,virtual reality(VR),once limited to high-end professional applications,is rapidly expanding into entertainment and broader consumer domains.However,the inherent contradiction between mo...With technological advancements,virtual reality(VR),once limited to high-end professional applications,is rapidly expanding into entertainment and broader consumer domains.However,the inherent contradiction between mobile hardware computing power and the demand for high-resolution,high-refresh-rate rendering has intensified,leading to critical bottlenecks,including frame latency and power overload,which constrain large-scale applications of VR systems.This study systematically analyzes four key technologies for efficient VR rendering:(1)foveated rendering,which dynamically reduces rendering precision in peripheral regions based on the physiological characteristics of the human visual system(HVS),thereby significantly decreasing graphics computation load;(2)stereo rendering,optimized through consistent stereo rendering acceleration algorithms;(3)cloud rendering,utilizing object-based decomposition and illumination-based decomposition for distributed resource scheduling;and(4)low-power rendering,integrating parameter-optimized rendering,super-resolution technology,and frame-generation technology to enhance mobile energy efficiency.Through a systematic review of the core principles and optimization approaches of these technologies,this study establishes research benchmarks for developing efficient VR systems that achieve high fidelity and low latency while providing further theoretical support for the engineering implementation and industrial advancement of VR rendering technologies.展开更多
Background Physics-based differentiable rendering(PBDR)aims to propagate gradients from scene parameters to image pixels or vice versa.The physically correct gradients obtained can be used in various applications,incl...Background Physics-based differentiable rendering(PBDR)aims to propagate gradients from scene parameters to image pixels or vice versa.The physically correct gradients obtained can be used in various applications,including inverse rendering and machine learning.Currently,two categories of methods are prevalent in the PBDR community:reparameterization and boundary sampling methods.The state-of-the-art boundary sampling methods rely on a guiding structure to calculate the gradients efficiently.They utilize the rays generated in traditional path-tracing methods and project them onto the object silhouette boundary to initialize the guiding structure.Methods In this study,we propose an augmentation of previous projective-sampling-based boundary-sampling methods in a bidirectional manner.Specifically,we utilize the rays spawned from the sensors and also employ the rays emitted by the emitters to initialize the guiding structure.Results To demonstrate the benefits of our technique,we perform a comparative analysis of differentiable rendering and inverse rendering performance.We utilize a range of synthetic scene examples and evaluate our method against state-of-the-art projective-sampling-based differentiable rendering methods.Conclusions The experiments show that our method achieves lower variance gradients in the forward differentiable rendering process and better geometry reconstruction quality in the inverse-rendering results.展开更多
Currently,the main idea of iterative rendering methods is to allocate a fixed number of samples to pixels that have not been fully rendered by calculating the completion rate.It is obvious that this strategy ignores t...Currently,the main idea of iterative rendering methods is to allocate a fixed number of samples to pixels that have not been fully rendered by calculating the completion rate.It is obvious that this strategy ignores the changes in pixel values during the previous rendering process,which may result in additional iterative operations.展开更多
Background In recent years,the demand for interactive photorealistic three-dimensional(3D)environments has increased in various fields,including architecture,engineering,and entertainment.However,achieving a balance b...Background In recent years,the demand for interactive photorealistic three-dimensional(3D)environments has increased in various fields,including architecture,engineering,and entertainment.However,achieving a balance between the quality and efficiency of high-performance 3D applications and virtual reality(VR)remains challenging.Methods This study addresses this issue by revisiting and extending view interpolation for image-based rendering(IBR),which enables the exploration of spacious open environments in 3D and VR.Therefore,we introduce multimorphing,a novel rendering method based on the spatial data structure of 2D image patches,called the image graph.Using this approach,novel views can be rendered with up to six degrees of freedom using only a sparse set of views.The rendering process does not require 3D reconstruction of the geometry or per-pixel depth information,and all relevant data for the output are extracted from the local morphing cells of the image graph.The detection of parallax image regions during preprocessing reduces rendering artifacts by extrapolating image patches from adjacent cells in real-time.In addition,a GPU-based solution was presented to resolve exposure inconsistencies within a dataset,enabling seamless transitions of brightness when moving between areas with varying light intensities.Results Experiments on multiple real-world and synthetic scenes demonstrate that the presented method achieves high"VR-compatible"frame rates,even on mid-range and legacy hardware,respectively.While achieving adequate visual quality even for sparse datasets,it outperforms other IBR and current neural rendering approaches.Conclusions Using the correspondence-based decomposition of input images into morphing cells of 2D image patches,multidimensional image morphing provides high-performance novel view generation,supporting open 3D and VR environments.Nevertheless,the handling of morphing artifacts in the parallax image regions remains a topic for future research.展开更多
High-fidelity tactile rendering offers significant potential for improving the richness and immersion of touchscreen interactions.This study focuses on a quantitative description of tactile rendering fidelity using a ...High-fidelity tactile rendering offers significant potential for improving the richness and immersion of touchscreen interactions.This study focuses on a quantitative description of tactile rendering fidelity using a custom-designed hybrid electrovibration and mechanical vibration(HEM)device.An electrovibration and mechanical vibration(EMV)algorithm that renders 3D gratings with different physical heights was proposed and shown to achieve 81%accuracy in shape recognition.Models of tactile rendering fidelity were established based on the evaluation of the height discrimination threshold,and the psychophysical-physical relationships between the discrimination and reference heights were well described by a modification of Weber’s law,with correlation coefficients higher than 0.9.The physiological-physical relationship between the pulse firing rate and the physical stimulation voltage was modeled using the Izhikevich spiking model with a logarithmic relationship.展开更多
The utilization of phosphors that achieve full-spectrum lighting has emerged as a prevailing trend in the advancement of white light-emitting diode(WLED)lighting.In this study,we successfully prepared a novel green ph...The utilization of phosphors that achieve full-spectrum lighting has emerged as a prevailing trend in the advancement of white light-emitting diode(WLED)lighting.In this study,we successfully prepared a novel green phosphor Ba_(2)Sc_(2)((BO_(3))_(2)B_(2)O_(5)):Ce^(3+)(BSBO:Ce^(3+))that can be utilized for full-spectrum lighting and low-temperature sensors.BSBO:Ce^(3+)exhibits a broad-band excitation spectrum centered at 410 nm,and a broad-band emission spectrum centered at 525 nm.The internal and external quantum efficiencies of BSBO:Ce^(3+)are 99%and 49%,respectively.The thermal stability of BSBO:Ce^(3+)can be improved by substituting partial Sc atoms with smaller cations.The thermal quenching mechanism of BSBO:Ce^(3+)and the lattice occupancy of Ce ions in BSBO are discussed in detail.Furthermore,by combining the green phosphor BSBO:Ce^(3+),the commercial blue phosphor and the red phosphor on a 405 nm chip,a white light source was obtained with a high average color rendering index(CRI)of 96.6,a low correlated color temperature(CCT)of 3988 K,and a high luminous efficacy of 88.0 Im/W.The lu-minous efficacy of the WLED exhibits negligible degradation during the 1000 h light aging experiment.What's more,an emission peak at 468 nm appears when excited at 352 nm and 80 K,however,the relative intensity of the peaks at 468 and 525 nm gradually weakens with increasing temperature,indicating the potential of this material as a low-temperature sensor.展开更多
动态电压恢复器(dynamic voltage restorer,DVR)的补偿策略对于补偿效果有很大影响。针对传统分析方法的不足,提出一种基于暂降前负荷电压的相量图分析方法,该方法物理概念清晰,确定DVR补偿范围时简洁方便,在分析复杂电压暂降的补偿策...动态电压恢复器(dynamic voltage restorer,DVR)的补偿策略对于补偿效果有很大影响。针对传统分析方法的不足,提出一种基于暂降前负荷电压的相量图分析方法,该方法物理概念清晰,确定DVR补偿范围时简洁方便,在分析复杂电压暂降的补偿策略时具有很大优势,且可适用于负荷不平衡情形。给出该分析方法的基本思路与过程,并以三单相桥共用直流母线型DVR为例,对其补偿策略进行研究,通过该方法实现在发生不平衡电压暂降且负荷不平衡时最小能量的补偿策略,并给出实现零有功补偿的条件,有效地延长了DVR补偿时间。仿真结果验证了该方法的正确性。展开更多
基金Supported by the National Key R&D Program of China under grant No.2022YFB3303203the National Natural Science Foundation of China under grant No.62272275.
文摘With technological advancements,virtual reality(VR),once limited to high-end professional applications,is rapidly expanding into entertainment and broader consumer domains.However,the inherent contradiction between mobile hardware computing power and the demand for high-resolution,high-refresh-rate rendering has intensified,leading to critical bottlenecks,including frame latency and power overload,which constrain large-scale applications of VR systems.This study systematically analyzes four key technologies for efficient VR rendering:(1)foveated rendering,which dynamically reduces rendering precision in peripheral regions based on the physiological characteristics of the human visual system(HVS),thereby significantly decreasing graphics computation load;(2)stereo rendering,optimized through consistent stereo rendering acceleration algorithms;(3)cloud rendering,utilizing object-based decomposition and illumination-based decomposition for distributed resource scheduling;and(4)low-power rendering,integrating parameter-optimized rendering,super-resolution technology,and frame-generation technology to enhance mobile energy efficiency.Through a systematic review of the core principles and optimization approaches of these technologies,this study establishes research benchmarks for developing efficient VR systems that achieve high fidelity and low latency while providing further theoretical support for the engineering implementation and industrial advancement of VR rendering technologies.
基金Supported by National Natural Science Foundation of China(No.62072020)the Leading Talents in Innovation and Entrepreneurship of Qingdao,China(19-3-2-21-zhc).
文摘Background Physics-based differentiable rendering(PBDR)aims to propagate gradients from scene parameters to image pixels or vice versa.The physically correct gradients obtained can be used in various applications,including inverse rendering and machine learning.Currently,two categories of methods are prevalent in the PBDR community:reparameterization and boundary sampling methods.The state-of-the-art boundary sampling methods rely on a guiding structure to calculate the gradients efficiently.They utilize the rays generated in traditional path-tracing methods and project them onto the object silhouette boundary to initialize the guiding structure.Methods In this study,we propose an augmentation of previous projective-sampling-based boundary-sampling methods in a bidirectional manner.Specifically,we utilize the rays spawned from the sensors and also employ the rays emitted by the emitters to initialize the guiding structure.Results To demonstrate the benefits of our technique,we perform a comparative analysis of differentiable rendering and inverse rendering performance.We utilize a range of synthetic scene examples and evaluate our method against state-of-the-art projective-sampling-based differentiable rendering methods.Conclusions The experiments show that our method achieves lower variance gradients in the forward differentiable rendering process and better geometry reconstruction quality in the inverse-rendering results.
基金supported partially by the National Natural Science Foundation of China(No.U19A2063)the Jilin Provincial Science&Technology Development Program of China(No.20230201080GX)。
文摘Currently,the main idea of iterative rendering methods is to allocate a fixed number of samples to pixels that have not been fully rendered by calculating the completion rate.It is obvious that this strategy ignores the changes in pixel values during the previous rendering process,which may result in additional iterative operations.
基金Supported by the Bavarian Academic Forum(BayWISS),as a part of the joint academic partnership digitalization program.
文摘Background In recent years,the demand for interactive photorealistic three-dimensional(3D)environments has increased in various fields,including architecture,engineering,and entertainment.However,achieving a balance between the quality and efficiency of high-performance 3D applications and virtual reality(VR)remains challenging.Methods This study addresses this issue by revisiting and extending view interpolation for image-based rendering(IBR),which enables the exploration of spacious open environments in 3D and VR.Therefore,we introduce multimorphing,a novel rendering method based on the spatial data structure of 2D image patches,called the image graph.Using this approach,novel views can be rendered with up to six degrees of freedom using only a sparse set of views.The rendering process does not require 3D reconstruction of the geometry or per-pixel depth information,and all relevant data for the output are extracted from the local morphing cells of the image graph.The detection of parallax image regions during preprocessing reduces rendering artifacts by extrapolating image patches from adjacent cells in real-time.In addition,a GPU-based solution was presented to resolve exposure inconsistencies within a dataset,enabling seamless transitions of brightness when moving between areas with varying light intensities.Results Experiments on multiple real-world and synthetic scenes demonstrate that the presented method achieves high"VR-compatible"frame rates,even on mid-range and legacy hardware,respectively.While achieving adequate visual quality even for sparse datasets,it outperforms other IBR and current neural rendering approaches.Conclusions Using the correspondence-based decomposition of input images into morphing cells of 2D image patches,multidimensional image morphing provides high-performance novel view generation,supporting open 3D and VR environments.Nevertheless,the handling of morphing artifacts in the parallax image regions remains a topic for future research.
基金Supported by the National Natural Science Foundation of China under Grants 61631010 and 61806085.
文摘High-fidelity tactile rendering offers significant potential for improving the richness and immersion of touchscreen interactions.This study focuses on a quantitative description of tactile rendering fidelity using a custom-designed hybrid electrovibration and mechanical vibration(HEM)device.An electrovibration and mechanical vibration(EMV)algorithm that renders 3D gratings with different physical heights was proposed and shown to achieve 81%accuracy in shape recognition.Models of tactile rendering fidelity were established based on the evaluation of the height discrimination threshold,and the psychophysical-physical relationships between the discrimination and reference heights were well described by a modification of Weber’s law,with correlation coefficients higher than 0.9.The physiological-physical relationship between the pulse firing rate and the physical stimulation voltage was modeled using the Izhikevich spiking model with a logarithmic relationship.
基金the National Natural Science Foundation of China(22003035,21963006,22073061)the Project of Shaanxi Province Youth Science and Technology New Star(2023KJXX-076)the National Training Program of Innovation and Entrepreneurship for Undergraduates(202314390018)。
文摘The utilization of phosphors that achieve full-spectrum lighting has emerged as a prevailing trend in the advancement of white light-emitting diode(WLED)lighting.In this study,we successfully prepared a novel green phosphor Ba_(2)Sc_(2)((BO_(3))_(2)B_(2)O_(5)):Ce^(3+)(BSBO:Ce^(3+))that can be utilized for full-spectrum lighting and low-temperature sensors.BSBO:Ce^(3+)exhibits a broad-band excitation spectrum centered at 410 nm,and a broad-band emission spectrum centered at 525 nm.The internal and external quantum efficiencies of BSBO:Ce^(3+)are 99%and 49%,respectively.The thermal stability of BSBO:Ce^(3+)can be improved by substituting partial Sc atoms with smaller cations.The thermal quenching mechanism of BSBO:Ce^(3+)and the lattice occupancy of Ce ions in BSBO are discussed in detail.Furthermore,by combining the green phosphor BSBO:Ce^(3+),the commercial blue phosphor and the red phosphor on a 405 nm chip,a white light source was obtained with a high average color rendering index(CRI)of 96.6,a low correlated color temperature(CCT)of 3988 K,and a high luminous efficacy of 88.0 Im/W.The lu-minous efficacy of the WLED exhibits negligible degradation during the 1000 h light aging experiment.What's more,an emission peak at 468 nm appears when excited at 352 nm and 80 K,however,the relative intensity of the peaks at 468 and 525 nm gradually weakens with increasing temperature,indicating the potential of this material as a low-temperature sensor.
文摘动态电压恢复器(dynamic voltage restorer,DVR)的补偿策略对于补偿效果有很大影响。针对传统分析方法的不足,提出一种基于暂降前负荷电压的相量图分析方法,该方法物理概念清晰,确定DVR补偿范围时简洁方便,在分析复杂电压暂降的补偿策略时具有很大优势,且可适用于负荷不平衡情形。给出该分析方法的基本思路与过程,并以三单相桥共用直流母线型DVR为例,对其补偿策略进行研究,通过该方法实现在发生不平衡电压暂降且负荷不平衡时最小能量的补偿策略,并给出实现零有功补偿的条件,有效地延长了DVR补偿时间。仿真结果验证了该方法的正确性。
