Multi‐planar plenoptic displays

Multi‐planar plenoptic displays consist of multiple spatially varying light‐emitting and light‐modulating planes. In this work, we introduce a framework to display light field data on this new type of display device. First, we present a mathematical notation that describes each of the layers in terms of the corresponding light transport operators. Next, we explain an algorithm that renders a light field with depth into a given multi‐planar plenoptic display and analyze the approximation error. We show two different physical prototypes that we have designed and built: The first design uses a dynamic parallax barrier and a number of bi‐state (translucent/opaque) screens. The second design uses a beam splitter to co‐locate two pairs of parallax barriers and static image projection screens. We evaluate both designs on a number of different 3D scenes. Finally, we present simulated and real results for different display configurations.     

Multi‐Layered Automultiscopic Displays

Our hybrid display model combines multiple automultiscopic elements volumetrically to support horizontal and vertical parallax at a larger depth of field and better accommodation cues compared to single layer elements. In this paper, we introduce a framework to analyze the bandwidth of such display devices. Based on this analysis, we show that multiple layers can achieve a wider depth of field using less bandwidth compared to single layer displays. We present a simple algorithm to distribute an input light field to multiple layers, and devise an efficient ray tracing algorithm for synthetic scenes. We demonstrate the effectiveness of our approach by both software simulation and two corresponding hardware prototypes.     

Dual layered display that presents auto‐stereoscopic 3D images to multiple viewers in arbitrary positions

Dual layered display or also called tensor display that consists of two panels in a stack can present full‐parallax 3D images with high resolution and continuous motion parallax by reconstructing corresponding light ray field within a viewing angle. The depth range where the 3D images can be displayed with reasonable resolution, however, is limited around the panel stack. In this paper, we propose a dual layered display that can present stereoscopic images to multiple viewers located at arbitrary positions in observer space with high resolution and large depth range. Combined with the viewer tracking system, the proposed method provides a practical way to realize high‐resolution large‐depth auto‐stereoscopic 3D display for multiple observers without restriction on the observer position and the head orientation.     

Visualization and Computer Graphics on Isotropically Emissive Volumetric Displays

The availability of commodity volumetric displays provides ordinary users with a new means of visualizing 3D data. Many of these displays are in the class of isotropically emissive light devices, which are designed to directly illuminate voxels in a 3D frame buffer, producing x-ray-like visualizations. While this technology can offer intuitive insight into a 3D object, the visualizations are perceptually different from what a computer graphics or visualization system would render on a 2D screen. This paper formalizes rendering on isotropically emissive displays and introduces a novel technique that emulates traditional rendering effects on isotropically emissive volumetric displays, delivering results that are much closer to what is traditionally rendered on regular 2D screens. Such a technique can significantly broaden the capability and usage of isotropically emissive volumetric displays. Our method takes a 3D data set or object as the input, creates an intermediate light field, and outputs a special 3D volume data set called a lumi-volume. This lumi-volume encodes approximated rendering effects in a form suitable for display with accumulative integrals along unobtrusive rays. When a lumi-volume is fed directly into an isotropically emissive volumetric display, it creates a 3D visualization with surface shading effects that are familiar to the users. The key to this technique is an algorithm for creating a 3D lumi-volume from a 4D light field. In this paper, we discuss a number of technical issues, including transparency effects due to the dimension reduction and sampling rates for light fields and lumi-volumes. We show the effectiveness and usability of this technique with a selection of experimental results captured from an isotropically emissive volumetric display, and we demonstrate its potential capability and scalability with computer-simulated high-resolution results.     

Direct light field rendering without 2D image generation

Rapid developments in 3D display technologies have enabled consumers to enjoy 3D environments in an increasingly immersive manner through various display systems such as stereoscopic, multiview, and light field displays. However, there is a corresponding increase in the complexity of the conventional multiview rendering process in the attempt to achieve a sufficient level of reality, which may hinder the further commercial viability of 3D display products based on such a conventional approach. This paper proposes a novel method, the so‐called direct light field rendering, which can compose the display 3D panel image without reconstructing all the multiview images beforehand. Interpreting the 3D display as sampling in the light field domain, we attempt to directly compute only the necessary samples, not the entire light fields or multiview images. Our proposed algorithm involves the solving of linear systems of two variables, thereby requiring remarkably low computational complexities. Experimental results show that the computation time and memory usage remain as little as 12% and 1% of those required by the conventional one.     

基于光场扫描的真三维立体显示系统的开发

近年来,计算机视觉领域出现了一种新型的三维显示技术,即光场三维显示技术。基于光场扫描的真三维立体显示系统通过重构物体光强的空间分布,减少了信息冗余,采用高速投影仪、定向散射反射镜和高速旋转马达等设计而成。通过分析光场三维显示原理和系统工作原理、显示系统架构和立体成像原理等,详细论述了显示系统开发的可行性,并通过实验证明了当达到一定投影输出功率和马达旋转功率时可实现立体成像。观测者可360度裸眼观测立体图像,并且无需佩戴任何辅助工具。     

Self‐calibration three‐dimensional light field display based on scalable multi‐LCDs

Approach to achieve self‐calibration three‐dimensional (3D) light field display is investigated in this paper. The proposed 3D light field display is constructed up on spliced multi‐LCDs, lens and diaphragm arrays, and directional diffuser. The light field imaging principle, hardware configuration, diffuser characteristic, and image reconstruction simulation are described and analyzed, respectively. Besides the light field imaging, a self‐calibration method is proposed to improve the imaging performance. An image sensor is deployed to capture calibration patterns projected onto and then reflected by the polymer dispersed liquid crystal film, which is attached to and shaped the diffuser. These calibration components are assembled with the display unit and can be switched between display mode and calibration mode. In the calibration mode, the imperfect imaging relations of optical components are captured and calibrated automatically. We demonstrate our design by implementing the prototype of proposed 3D light field display by using modified off‐the‐shelf products. The proposed approach successfully meets the requirement of real application on scalable configuration, fast calibration, large viewing angular range, and smooth motion parallax.     

基于TFT LCD的立体显示技术研究

裸眼立体显示器使用特殊的光学方法能产生左右眼互不干扰的独立视区,由于其能使立体对图像与眼睛正确对应,因此不需要配戴立体眼镜等视图分隔装置也可以获得立体感.为了实现高清晰无闪烁的裸眼立体显示,在简述几种典型的基于TFT LCD的立体显示技术的基础上,选择线光源照明法作为重点研究对象,先分析了左右视图截面光路的特点,然后利用菲林曝光方法制造光栅胶片,设计了一种产生线光源的照明板,最后探讨了立体显示器的基本结构,并据此开发了一种基于TFT LCD的立体显示器.实验结果表明,研制的样机可以获得高清晰无闪烁的裸眼立体显示.     

Microfabrication of a spherically curved liquid crystal display enabling the integration in a smart contact lens

A spherically curved liquid crystal display based on a guest-host liquid crystal configuration is fabricated. An asymmetric display design is introduced: two flexible display substrates with varying surface area are used, allowing for compact integration of powering and driving electronics. A matrix of spacer structures composed of photosensitive adhesive and defined by photolithography, simultaneously provides the uniform cell gap while acting as glue between both display substrates. Using poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as transparent, conductive electrode layer and obliquely evaporated SiO₂ as alignment layer, a functional single-pixel display was fabricated. The display can be embedded in a smart contact lens, thereby enabling applications within the emerging biomedical field. An artificial iris, for example, could be designed to help people suffering from iris deficiencies that involve hypersensitivity to light.     

干涉型超光谱成像仪的星上定标技术研究

根据干涉型超光谱成像仪的原理、特点以及对星上定标的要求,介绍了几种星上定标技术,分析了几种定标方案的结构和优缺点。在一次像面上引入定标结构的方法是利用一次像面上狭缝两端的边视场或在狭缝旁开孔,引入定标光源实现定标。根据聚光结构的不同,定标光源使用聚光镜和自聚焦镜两种方案;全系统定标方法是通过摆镜旋转90°引入定标光源,可分为朗伯板定标系统和积分球定标系统。在实际设计中,根据光学系统、结构总体的实现可能性,选择了积分球定标系统的方案。经过分析对比,后者结构紧凑、光能量大,可实现全系统、全口径、部分视场定标。     

General design method for three-dimensional displays with horizontally asymmetric pixel structures

Various 3D displays have been proposed to show realistic and vivid 3D images. Moreover, 3D displays have been applied in various fields including medicine, entertainment, and advertising. Depending on the application, 3D displays have different pixel structures and sizes. In this paper, we present a 3D-display design method that can be applied regardless of the pixel structure and display sizes. The area of the designable 3D display is suggested by the improved 3D image quality. The manufactured displays are used to verify the proposed method. Furthermore, a light field simulation is performed to confirm the area that was not proven by the manufactured displays. With the proposed 3D image-quality model and 3D image simulation by the light field representation, a general design of 3D displays with various pixel structures can be developed.     

Programmable Imaging: Towards a Flexible Camera

In this paper, we introduce the notion of a programmable imaging system. Such an imaging system provides a human user or a vision system significant control over the radiometric and geometric characteristics of the system. This flexibility is achieved using a programmable array of micro-mirrors. The orientations of the mirrors of the array can be controlled with high precision over space and time. This enables the system to select and modulate rays from the scene’s light field based on the needs of the application at hand. We have implemented a programmable imaging system that uses a digital micro-mirror device (DMD), which is used in digital light processing. Although the mirrors of this device can only be positioned in one of two states, we show that our system can be used to implement a wide variety of imaging functions, including, high dynamic range imaging, feature detection, and object recognition. We also describe how a micro-mirror array that allows full control over the orientations of its mirrors can be used to instantly change the field of view and resolution characteristics of the imaging system. We conclude with a discussion on the implications of programmable imaging for computer vision.     

Light field morphing using 2D features

We present a 2D feature-based technique for morphing 3D objects represented by light fields. Existing light field morphing methods require the user to specify corresponding 3D feature elements to guide morph computation. Since slight errors in 3D specification can lead to significant morphing artifacts, we propose a scheme based on 2D feature elements that is less sensitive to imprecise marking of features. First, 2D features are specified by the user in a number of key views in the source and target light fields. Then the two light fields are warped view by view as guided by the corresponding 2D features. Finally, the two warped light fields are blended together to yield the desired light field morph. Two key issues in light field morphing are feature specification and warping of light field rays. For feature specification, we introduce a user interface for delineating 2D features in key views of a light field, which are automatically interpolated to other views. For ray warping, we describe a 2D technique that accounts for visibility changes and present a comparison to the ideal morphing of light fields. Light field morphing based on 2D features makes it simple to incorporate previous image morphing techniques such as nonuniform blending, as well as to morph between an image and a light field.     

An optimization method for parameters configuration of the light field display based on subjective evaluation

A light field display (LFD) can provide high immersion three-dimensional (3D) visual experience by accurately reconstructing the light field information of 3D objects, which usually require a large number of views and high resolution. However, the information capacity provided by the LFD is limited, so the view number and the view resolution are mutually constrained. Few effective standards or methods have been proposed to guide the configuration of the view number and the resolution, which can only be determined empirically. Here, an optimization method for parameters configuration of the LFD is proposed with four subjective experiments. The display quality of the LFD with different configurations between the view number and the view resolution is quantitatively evaluated. Accordingly, a physiological visual model (PVM) is established to depict the change rules and guide the parameters configuration. Experimental results demonstrate the validity of the proposed optimization method quantitatively and qualitatively, which will contribute to the researches of the LFD in the future.     

干涉型超光谱成像仪的星上定标技术研究

根据干涉型超光谱成像仪的原理、特点以及对星上定标的要求,介绍了几种星上定标技术,分析了几种定标方案的结构和优缺点。在一次像面上引入定标结构的方法是利用一次像面上狭缝两端的边视场或在狭缝旁开孔,引入定标光源实现定标。根据聚光结构的不同,定标光源使用聚光镜和自聚焦镜两种方案;全系统定标方法是通过摆镜旋转90°引入定标光源,可分为朗伯板定标系统和积分球定标系统。在实际设计中,根据光学系统、结构总体的实现可能性,选择了积分球定标系统的方案。经过分析对比,后者结构紧凑、光能量大,可实现全系统、全口径、部分视场定标。     

A flat thin display with RF electron generation

Abstract— A new type of a flat and thin display with a secondary‐emission electron source will be reported. In this display device, electrons are multiplied between two secondary emission plates under a high‐frequency electric field. This has a number of advantages over a field‐emission display: the emission comes from flat plates, which reduces the lifetime problems of ion bombardment of field‐emitter tips. Furthermore, the electron emission is space‐charge limited, which gives a uniform electron distribution. The electrons are extracted from the source and accelerated to a phosphor screen to generate light. Gray levels are made by pulse width modulation.     

Effects of Superimposition of a Head-Up Display on Driving Performance and Glance Behavior in the Elderly

A vehicle head-up display (HUD) has a semitransparent property that utilizes a method of projecting light onto the windshield. The semitransparent characteristic of the HUD generates continuous superimposition between the “HUD graphic” and “road environment events.” This study aims to determine the effects of HUD use on elderly driving. Two age groups (elderly, younger) performed tasks (speed monitoring, navigation) utilizing two types of display (HUD, head-down display) in two different circumstances (high superimposition level, low superimposition level). Subject performance was evaluated by having the subjects execute a secondary display task while performing a primary driving task with an eye-tracking task. In addition, the degree of driver visual distraction was verified through the measurement of display glance duration. The results showed that an increase in superimposition negatively affected driver glance duration independent of age. However, the use of HUD in low superimposition situations showed relative advantages with regard to display use independent of age. This study confirmed that the negative effects of HUD use need to be considered during the selection of HUD information and display location. In particular, this study verifies that special attention should be given to the negative effects of superimposition of text information for use by an elderly population.     

Modeling Color Properties of Tiled Displays

The concept of tiled displays can be successful only if such displays are made to look like a single display perceptually. The two issues that need to be solved to achieve this goal are geometric correction and color seamlessness of images spanning across tiles. Geometric correction algorithms borrow pin‐hole camera models to model projector display geometry. In this paper, we introduce an abstract modeling function that describes the color seen by a viewer when displayed by a display device. Though this function can be used to model color displayed by any common display device, in this paper, we use it to model color in multiprojector display systems. We use the model to explain the reasons for different types of color variations in a multiprojector display, to compare different color correction algorithms, and to derive such algorithms directly from the model.     

Development of 2D Microdisplay Using an Integrated Microresonating Waveguide Scanning System

Our research team has developed a 2D micro image display device that can potentially overcome the size reduction limits while maintaining the high-image resolution and field of view obtained by mirror-based display systems. The basic design of the optical scanner includes a microfabricated SU-8 cantilever waveguide that is electromechanically deflected by a piezoelectric actuator. From the distal tip of the cantilever waveguide, a light beam is emitted and the direction of propagation is displaced along two orthogonal directions. The waveforms for the actuator and the LED light modulation are generated and controlled using a field programmable gate array. Our recent study is an update to the previously-reported mechanical scanner, replacing the hand-built PZT scanner and fiber waveguide with a microfabricated system incorporating aerosol-deposited PZT thin film and a polymeric SU-8 wave guide. In this article, we report on the design and fabrication of a prototype miniaturized 2D scanner, discuss optical and mechanical the modeling of the system's properties and present the experimental results.     

基于LonWorks总线型智能有毒有害气体变送器的设计

介绍一种基于LonWorks总线型智能有毒有害气体变送器的工作原理、硬件电路设计和软件设计。这种智能变送器不仅具有大屏幕液晶显示、声光报警功能,而且带有LonWorks总线接口,能够广泛应用于LonWorks总线系统或其他DCS系统中。