Integral imaging-based tabletop light field 3D display with large viewing angle

Light field 3D display technology is considered a revolutionary technology to address the critical visual fatigue issues in the existing 3D displays.Tabletop light field 3D display provides a brand-new display form that satisfies multi-user shared viewing and collaborative works,and it is poised to become a potential alternative to the traditional wall and portable display forms.However,a large radial viewing angle and correct radial perspective and parallax are still out of reach for most current tabletop light field 3D displays due to the limited amount of spatial information.To address the viewing angle and perspective issues,a novel integral imaging-based tabletop light field 3D display with a simple flat-panel structure is proposed and developed by applying a compound lens array,two spliced 8K liquid crystal display panels,and a light shaping diffuser screen.The compound lens array is designed to be composed of multiple three-piece compound lens units by employing a reverse design scheme,which greatly extends the radial viewing angle in the case of a limited amount of spatial information and balances other important 3D display parameters.The proposed display has a radial viewing angle of 68.7°in a large display size of 43.5 inches,which is larger than the conventional tabletop light field 3D displays.The radial perspective and parallax are correct,and high-resolution 3D images can be reproduced in large radial viewing positions.We envision that this proposed display opens up possibility for redefining the display forms of consumer electronics.

Metasurfaces for near-eye display applications

Virtual reality(VR)and augmented reality(AR)are revolutionizing our lives.Near-eye displays are crucial technologies for VR and AR.Despite the rapid advances in near-eye display technologies,there are still challenges such as large field of view,high resolution,high image quality,natural free 3D effect,and compact form factor.Great efforts have been devoted to striking a balance between visual performance and device compactness.While traditional optics are nearing their limitations in addressing these challenges,ultra-thin metasurface optics,with their high light-modulating capabilities,may present a promising solution.In this review,we first introduce VR and AR near-eye displays,and then briefly explain the working principles of light-modulating metasurfaces,review recent developments in metasurface devices geared toward near-eye display applications,delved into several advanced natural 3D near-eye display technologies based on metasurfaces,and finally discuss about the remaining challenges and future perspectives associated with metasurfaces for near-eye display applications.

Wide color gamut switchable autostereoscopic 3D display based on directional quantum-dot backlight

A switchable autostereoscopic 3-dimensional(3D) display device with wide color gamut is introduced in this paper. In conjunction with a novel directional quantum-dot(QD) backlight, the precise scanning control strategy, and the eye-tracking system, this spatial-sequential solution enables our autostereoscopic display to combine all the advantages of full resolution,wide color gamut, low crosstalk, and switchable 2D/3D. And also, we fabricated an autostereoscopic display prototype and demonstrated its performances effectively. The results indicate that our system can both break the limitation of viewing position and provide high-quality 3D images. We present two working modes in this system. In the spatial-sequential mode,the crosstalk is about 6%. In the time-multiplexed mode, the viewer should wear auxiliary and the crosstalk is about 1%,just next to that of a commercial 3D display(BENQ XL2707-B and View Sonic VX2268 WM). Additionally, our system is also completely compatible with active shutter glasses and its 3D resolution is same as its 2D resolution. Because of the excellent properties of the QD material, the color gamut can be widely extended to 77.98% according to the ITU-R recommendation BT.2020(Rec.2020).

3D Flash Display for STL Model in Rapid Prototyping System

A kind of 3D color graphics display system for the STL model is developed by calling the functions from Open GL graphic library through VC++6.0 under the Windows environment in this paper. The STL model is a high quality one that can be quiescent or animated. This system is conducive to find out the disfigurement of the STL model in a rapid prototyping process and to repair it. Therefore, the component quality can be enhanced.

3D Product Display Based on Inventor Animation Design

With the rapid development of internet technology,some innovative fashion product are increasingly showed in the way of three-dimensional virtual display.Taking fashion jewelry as an example,the virtual 3D display method of product is studied by Inventor which is parametric 3D design software for efficient modeling and animation developed by the Autodesk Company.By discussing the methods of part feature creation and assembly design,the real simulation of the product is carried out.Three-dimensional animation techniques,such as fade animation,components animation and camera animation are used to depict product features and animation effects.

VLSI design of 3D display processing chip for binocular stereo displays

In order to develop the core chip supporting binocular stereo displays for head mounted display （HMD） and glasses-TV, a very large scale integrated （VISI） design scheme is proposed by using a pipeline architecture for 3D display processing chip （HMD100）. Some key techniques including stereo display processing and high precision video scaling based bicubic interpolation, and their hardware implementations which improve the image quality are presented. The proposed HMD100 chip is verified by the field-programmable gate array （FPGA）. As one of innovative and high integration SoC chips, HMD100 is designed by a digital and analog mixed circuit. It can support binocular stereo display, has better scaling effect and integration. Hence it is applicable in virtual reality （VR）, 3D games and other microdisplay domains.

Optimizing depth of field in 3D light-field display by analyzing and controlling light-beam divergence angle

A concept of divergence angle of light beams(DALB)is proposed to analyze the depth of field(DOF)of a 3D light-field display system.The mathematical model between DOF and DALB is established,and the conclusion that DOF and DALB are inversely proportional is drawn.To reduce DALB and generate clear depth perception,a triple composite aspheric lens structure with a viewing angle of 100°is designed and experimentally demonstrated.The DALB-constrained 3D light-field display system significantly improves the clarity of 3D images and also performs well in imaging at a 3D scene with a DOF over 30 cm.

Three-photon-excited fluorescence of Tb^(3+)-doped CaO-Al_2O_3-SiO_2 glass by femtosecond laser irradiation

A near infrared to visible blue, green, and red upconversion luminescence in a Tb^3＋-doped CaO-Al2O3-SiO2 glass was studied, which was excited using 800 nm femtosecond laser irradiation. The upconversion luminescence was attributed to ^5D3→^7F5, ^5D3→^7F4, ^5D3→^7F3, ^5D4→^7F6, ^5D4→^7F5, ^5D4→^7F4, and ^5D4→^7F3 transitions of Tb^3＋. The relationship between upconversion luminescence intensity and the pump power indicated that a three-photon simultaneous absorption process was dominant in this upconversion luminescence. The intense red, green, and blue upconversion luminescence of Tb^3＋-doped CaO-Al2O3-SiO2 glass may be potentially useful in developing three-dimensional display applications.

Model Implementation and Analysis of a True Three-dimensional Display System

To model a true three-dimensional(3D)display system,we introduced the method of voxel molding to obtain the stereoscopic imaging space of the system.For the distribution of each voxel,we proposed a four-dimensional(4D)Givone–Roessor(GR)model for state-space representation—that is,we established a local state-space model with the 3D position and one-dimensional time coordi-nates to describe the system.First,we extended the original elementary operation approach to a 4D condition and proposed the implementation steps of the realiza-tion matrix of the 4D GR model.Then,we described the working process of a true 3D display system,analyzed its real-time performance,introduced the fixed-point quantization model to simplify the system matrix,and derived the conditions for the global asymptotic stability of the system after quantization.Finally,we provided an example to prove the true 3D display system’s feasibility by simulation.The GR-model-representation method and its implementation steps proposed in this paper simplified the system’s mathematical expression and facilitated the microcon-troller software implementation.Real-time and stability analyses can be used widely to analyze and design true 3D display systems.

Grid-based computer-generated holograms synthesizing for holographic three-dimensional display

To reduce the computing time of composite computer-generated holograms （CGHs） gen- eration based upon the angular projection algorithm for holographic three-dimensional （3D） display, a grid-based holographic display （ GHD ） scheme was designed. The grid computing technology was applied to numerically process the different angular projections of an object in distributed-parallel manner to create the corresponding CGHs. The whole treatment of a projection was regarded as a job executed on the grid node machine. The number of jobs which were submitted to grid nodes, therefore, was equal to that of the projections of the object. A Condor-based grid testbed was constructed to verify the feasibility of the GHD scheme, and a graphical user interface （GUI） program and several service modules were developed for it. A 3D terrain model as an example was processed on the testbed. The result showed that the scheme was feasible and able to improve the execution elficiency greatly.

Swept-Volume Display System Based on Cylindrical Space Projection and Curved Reflectors

In order to achieve a clear and steady swept-volume display,the method of swept-volume display based on cylindrical space projection was presented. One projector generated the image volume in π× 70 mm × 70 mm × 150 mm space. Experimentally,the resolution of images was 800 pixel × 600 pixel × 360 pixel,which resulted in almost 345 million voxels. In order to achieve space voxels with uniform brightness, curved reflectors were also designed. In addition,the match conditions between triangles and the scanning planes in the volume space were classified and a sweptvolume graphics engine based on embedded platform was designed.The image rendering the hardware foundation for three-dimensional( 3D) dynamic images generation was achieved. Demonstrated in the experiments,light source utilization of the second-generation system based on curved mirror is about three times brighter than the firstgeneration 3D minitor based on flat mirror,and this system is able to display color,clear and well-proportioned 3D images in brighter room light.

Technical analysis of 3DTV and outstanding issues

This paper analyzes the technical characteristic of three-dimensional display technology （3DTV） system and some core technologies yet to be solved. It points out the ways to solve these problems and presents an effective solution for thediscomfort of watching the three-dimensional TV.

Dynamic Hyperlinker: Innovative Solution for 3D Video Content Search and Retrieval

Recently, 3D display technology, and content creation tools have been undergone rigorous development and as a result they have been widely adopted by home and professional users. 3D digital repositories are increasing and becoming available ubiquitously. However, searching and visualizing 3D content remains a great challenge. In this paper, we propose and present the development of a novel approach for creating hypervideos, which ease the 3D content search and retrieval. It is called the dynamic hyperlinker for 3D content search and retrieval process. It advances 3D multimedia navigability and searchability by creating dynamic links for selectable and clickable objects in the video scene whilst the user consumes the 3D video clip. The proposed system involves 3D video processing, such as detecting/tracking clickable objects, annotating objects, and metadata engineering including 3D content descriptive protocol. Such system attracts the attention from both home and professional users and more specifically broadcasters and digital content providers. The experiment is conducted on full parallax holoscopic 3D videos “also known as integral images”.

Large viewing angle holographic 3D display system based on maximum diffraction modulation

An ideal holographic 3D display should have the characteristics of large viewing angle,full color,and low speckle noise.However,the viewing angle of the holographic 3D display is usually limited by existing strategies,which vastly hinders its extensive application.In this paper,a large viewing angle holographic 3D display system based on maximum diffraction modulation is proposed.The core of the proposed system comprises the spatial light modulators(SLMs)and liquid crystal grating.We also present a new feasible scheme for the realization of large viewing angle holographic 3D display.This is achieved by considering the maximum diffraction angle of SLM as the limited diffraction modulation range of each image point.By doing so,we could not only give access to the maximum hologram size of the object,but also tune the reconstructed image of secondary diffraction by using a self-engineered liquid crystal grating.More importantly,the proposed maximum diffraction modulation scheme enables the viewing angle of the proposed system to be enlarged to 73.4°.The proposed system has huge application potential in the fields such as education,culture,and entertainment.

Wavelets and Continuous Wavelet Transform for Autostereoscopic Multiview Images

Recently, the reference functions for the synthesis and analysis of the autostereoscopic multiview and integral images in three-dimensional displays were introduced. In the current paper, we propose the wavelets to analyze such images. The wavelets are built on these reference functions as on the scaling functions of the wavelet analysis. The continuous wavelet transform was successfully applied to the testing wireframe binary objects. The restored locations correspond to the structure of the testing wireframe binary objects.

Computer-generated holograms for 3D display(Invited Paper)

We have been studying various types of computer-generated holograms for three-dimensional （3D） displays both for a real-time holographic video display and a hard copy, or a printed hologram. For the hard copy output, we have developed a direct fringe printer, which is achieved to print over 100 gigapixels computer-generated hologram with 0.44μm pitch. In this paper, we introduce our recent progresses on the rainbow hologram, the cylindrical holograms, and the disk hologram for 3D display.

Micro-projection dynamic backlight for multi-view 3D display

A micro-projection dynamic backlight for multi-view three-dimensional(3D)display is proposed.The proposed backlight includes a light emitting diodes(LEDs)array,a lenticular lens array,and a scattering film.The LED array,the lenticular lens,and the scattering film construct a micro-projection structure.In this structure,the LEDs in the array are divided into several groups.The light from each LED group can be projected to the scattering film by the lenticular lens and forms a series of bright stripes.The different LED groups have different horizontal positions,so these bright stripes corresponding to different LED groups also have different horizontal positions.Therefore,they can be used as a dynamic backlight.Because the distance between the LEDs array and the lenticular lens is much larger than the distance between the lenticular lens and the scattering films,the imaging progress will make the width of the bright stripes much smaller than that of the LEDs,and the pitch of the stripes is also decreased.According to the 3D display theory,the bright stripes with small width and pitch help to increase the number of views.Therefore,the proposed micro-projection dynamic backlight is very suitable for multi-view 3D display.An experimental prototype was developed,and the experimental results show that the micro-projection dynamic backlight can correctly complete the directional projection of the parallax images to form a 3D display.

360° light field 3D display system based on a triplet lenses array and holographic functional screen

A 360° light field 3D display system is presented, which consists of a liquid crystal display, a novel triplet lenses array, and a holographic functional screen （HFS）. The mapping relationship among pixels, 3D objects, and view- ing positions are investigated. The aberration analysis of the single lens is carried out both in the simulation and the experiment, which shows that it cannot provide an excellent 3D image to the viewers. In order to suppress the aberrations, ＂the primary aberration theory＂ and ＂the damped least-squares method＂ are used for optical analysis and lens design. A 3D image with aberration correction can be viewed around the proposed display system.

A penetrable interactive 3D display based on motion recognition(Invited Paper)

Based on light field reconstruction and motion recognition technique, a penetrable interactive floating 3D display system is proposed. The system consists of a high-frame-rate projector, a flat directional diffusing screen, a high-speed data transmission module, and a Kinect somatosensory device. The floating occlusioncorrect 3D image could rotate around some axis at different speeds according to user＇s hand motion. Eight motion directions and speed are detected accurately, and the prototype system operates efficiently with a recognition accuracy of 90% on average.

3D displays: toward holographic video displays of 3D images

As the fiat panel displays （Liquid Crystal Displays, AMOLED, etc.） reach near perfection in their viewing qualities and display areas, it is natural to seek the next level of displays, including 3D displays. There is a strong surge in 3D liquid crystal displays as a result of the successful movie Avatar. Most of these 3D displays involve the employment of special glasses that allow one view perspective for each of the eyes to achieve a depth perception. Such displays are not real 3D displays. In fact, these displays can only provide one viewing perspective for all viewers, regardless of the viewer＇s position. In addition, a fundamental viewing problem of focusing and accommodation exist that can lead to discomfort and fatigue for many viewers. In this paper, the authors review the current status of stereoscopic 3D displays and their problems. The authors will also discuss the possibility of using fiat panels for the display of both phase and intensity of video image information, leading to the ultimate display of 3D holographic video images. Many of the fundamental issues and limitations will be presented and discussed.