Virtual reality （VR） is a scientific method and technology created during the exploration of the nature by human beings to understand, simulate, and better adapt and use the nature. Based on the analysis on the whol...Virtual reality （VR） is a scientific method and technology created during the exploration of the nature by human beings to understand, simulate, and better adapt and use the nature. Based on the analysis on the whole process of VR, this paper presents different categories of VR problems and a type of theoretical expression, and abstracts three kinds of scientific and technical problems in VR field. On the basis of foresaid content, this paper also studies current major research objectives, research results and development trend of VR in the aspects of VR modeling method, VR representation technology, human-machine interaction and devices, VR development suites and supporting infrastructure, as well as VR applications. Finally, several theoretical and technical problems that need to be further studied and solved are addressed.展开更多
The pioneers of holography,Gabor,Leith,Upatnieks,and Denisyuk,predicted very early that the ultimate 3D display will be based on this technique.This conviction was rooted on the fact that holography is the only approa...The pioneers of holography,Gabor,Leith,Upatnieks,and Denisyuk,predicted very early that the ultimate 3D display will be based on this technique.This conviction was rooted on the fact that holography is the only approach that can render all optical cues interpreted by the human visual system.Holographic 3D displays have been a dream chased after for many years,facing challenges on all fronts:computation,transmission,and rendering.With numbers such as 6.6×10^(15) flops required for calculations,3×10^(15) b/s data rates,and 1.6×10^(12) phase pixels,the task has been daunting.This article is reviewing the recent accomplishments made in the field of holographic 3D display.Specifically,the new developments in machine learning and neural network algorithms demonstrating that computer-generated holograms approach real-time processing.A section also discuss the problem of data transmission that can arguably be solved using clever compression algorithms and optical fiber transmission lines.Finally,we introduce the last obstacle to holographic 3D display,which is is the rendering hardware.However,there is no further mystery.With larger and faster spatial light modulators(SLMs),holographic projection systems are constantly improving.The pixel count on liquid crystal on silicon(LCoS)as well as microelectromechanical systems(MEMS)phase displays is increasing by the millions,and new photonic integrated circuit phased arrays are achieving real progress.It is only a matter of time for these systems to leave the laboratory and enter the consumer world.The future of 3D displays is holographic,and it is happening now.展开更多
Realizing a high color rendering index(CRI)in Ce:LuAG transparent ceramics(TCs)with desired thermal stability is essential to their applications in white LEDs/LDs as color converters.In this study,based on the scheme ...Realizing a high color rendering index(CRI)in Ce:LuAG transparent ceramics(TCs)with desired thermal stability is essential to their applications in white LEDs/LDs as color converters.In this study,based on the scheme of configuring the red component by Cr^(3+) doping,an efficient spectral regulation was realized in Ce,Cr:LuAG TCs.A unilateral shift phenomenon could be observed in both photoluminescence(PL)and photoluminescence excitation(PLE)spectra of TCs.By constructing TC-based white LED/LD devices in a remote excitation mode,luminescence properties of Ce,Cr:LuAG TCs were systematically investigated.The CRI values of Ce:LuAG TC based white LEDs could be increased by a magnitude of 46.2%.Particularly,by combining the as fabricated Ce,Cr:LuAG TCs with a 0.5 at% Ce:YAG TC,surprising CRI values of 88 and 85.5 were obtained in TC based white LEDs and LDs,respectively.Therefore,Ce,Cr:LuAG TC is a highly promising color convertor for high-power white LEDs/LDs applied in general lighting and displaying.展开更多
This paper presents a novel algorithm for synthesizing animations of running water, such as water- falls and rivers, in the style of Chinese paintings, for applications such as cartoon making. All video frames are fir...This paper presents a novel algorithm for synthesizing animations of running water, such as water- falls and rivers, in the style of Chinese paintings, for applications such as cartoon making. All video frames are first registered in a common coordinate system, simultaneously segmenting the water from background and computing optical flow of the water. Taking artists＇ advice into account, we produce a painting structure to guide painting of brush strokes. Flow lines are placed in the water following an analysis of variance of optical flow, to cause strokes to be drawn where the water is flowing smoothly, rather than in turbulent areas： this allows a few moving strokes to depict the trends of the water flows. A variety of brush strokes is then drawn using a template determined from real Chinese paintings. The novel contributions of this paper are： a method for painting structure generation for flows in videos, and a method for stroke placement, with the necessary temporal coherence.展开更多
基金Supported by the National Basic Research Program of China (Grant No. 2009CB320805)the National Natural Science Foundation of China(Grant Nos. 60533070, 60503066)the National High-Tech Research & Development Program of China (Grant Nos. 2006AA01Z333,2006AA01Z311)
文摘Virtual reality （VR） is a scientific method and technology created during the exploration of the nature by human beings to understand, simulate, and better adapt and use the nature. Based on the analysis on the whole process of VR, this paper presents different categories of VR problems and a type of theoretical expression, and abstracts three kinds of scientific and technical problems in VR field. On the basis of foresaid content, this paper also studies current major research objectives, research results and development trend of VR in the aspects of VR modeling method, VR representation technology, human-machine interaction and devices, VR development suites and supporting infrastructure, as well as VR applications. Finally, several theoretical and technical problems that need to be further studied and solved are addressed.
文摘The pioneers of holography,Gabor,Leith,Upatnieks,and Denisyuk,predicted very early that the ultimate 3D display will be based on this technique.This conviction was rooted on the fact that holography is the only approach that can render all optical cues interpreted by the human visual system.Holographic 3D displays have been a dream chased after for many years,facing challenges on all fronts:computation,transmission,and rendering.With numbers such as 6.6×10^(15) flops required for calculations,3×10^(15) b/s data rates,and 1.6×10^(12) phase pixels,the task has been daunting.This article is reviewing the recent accomplishments made in the field of holographic 3D display.Specifically,the new developments in machine learning and neural network algorithms demonstrating that computer-generated holograms approach real-time processing.A section also discuss the problem of data transmission that can arguably be solved using clever compression algorithms and optical fiber transmission lines.Finally,we introduce the last obstacle to holographic 3D display,which is is the rendering hardware.However,there is no further mystery.With larger and faster spatial light modulators(SLMs),holographic projection systems are constantly improving.The pixel count on liquid crystal on silicon(LCoS)as well as microelectromechanical systems(MEMS)phase displays is increasing by the millions,and new photonic integrated circuit phased arrays are achieving real progress.It is only a matter of time for these systems to leave the laboratory and enter the consumer world.The future of 3D displays is holographic,and it is happening now.
基金the National Natural Science Foundation of China(61975070,51902143,61971207,and 61775088)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)+6 种基金Key Research and Development Project of Jiangsu Province(BE2018062,BE2019033)Natural Science foundation of Jiangsu Province(BK20191467)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX20_2336)International S&T Cooperation Program of Jiangsu Province(BZ2019063,BZ2020045,and BZ2020030)Natural Science Foundation of the Jiangsu Higher Education Institutes of China(19KJB43001&20KJA430003)Special Project for Technology Innovation of Xuzhou City(KC19250,KC20201,and KC20244)Open Project of State Key Laboratory of Advanced Materials and Electronic Components(FHR-JS-202011017).
文摘Realizing a high color rendering index(CRI)in Ce:LuAG transparent ceramics(TCs)with desired thermal stability is essential to their applications in white LEDs/LDs as color converters.In this study,based on the scheme of configuring the red component by Cr^(3+) doping,an efficient spectral regulation was realized in Ce,Cr:LuAG TCs.A unilateral shift phenomenon could be observed in both photoluminescence(PL)and photoluminescence excitation(PLE)spectra of TCs.By constructing TC-based white LED/LD devices in a remote excitation mode,luminescence properties of Ce,Cr:LuAG TCs were systematically investigated.The CRI values of Ce:LuAG TC based white LEDs could be increased by a magnitude of 46.2%.Particularly,by combining the as fabricated Ce,Cr:LuAG TCs with a 0.5 at% Ce:YAG TC,surprising CRI values of 88 and 85.5 were obtained in TC based white LEDs and LDs,respectively.Therefore,Ce,Cr:LuAG TC is a highly promising color convertor for high-power white LEDs/LDs applied in general lighting and displaying.
基金Supported partially by the National Basic Research Program of China (Grant No.2006CB303105)the National Natural Science Foundation of China (Grant No.U0735001)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No.20060003057)an EPSRC UK travel grant
文摘This paper presents a novel algorithm for synthesizing animations of running water, such as water- falls and rivers, in the style of Chinese paintings, for applications such as cartoon making. All video frames are first registered in a common coordinate system, simultaneously segmenting the water from background and computing optical flow of the water. Taking artists＇ advice into account, we produce a painting structure to guide painting of brush strokes. Flow lines are placed in the water following an analysis of variance of optical flow, to cause strokes to be drawn where the water is flowing smoothly, rather than in turbulent areas： this allows a few moving strokes to depict the trends of the water flows. A variety of brush strokes is then drawn using a template determined from real Chinese paintings. The novel contributions of this paper are： a method for painting structure generation for flows in videos, and a method for stroke placement, with the necessary temporal coherence.
