Synchronous 2D/3D Switching System for Service‐Compatible 3DTV Broadcasting

This paper proposes a new broadcasting system for the service‐compatible 3DTV in which the 3D service can coexist with the conventional digital TV broadcast. In the proposed system, the commercial 3DTV service can be implemented via the existing DTV channel without utilizing the dedicated 3DTV system. This 2D/3D system interworks with the conventional system and can switch to 2D or 3D service according to the broadcast programming and schedule. The system also provides a mechanism that can prevent the synchronization mismatch between left and right video streams and between the stream and the associated signaling in the 2D/3D transition periods. The picture quality measurements are carried out based on the ITU‐R recommended test to check the level of quality of service provided by the proposed scheme. The conformity tests are also performed with the conventional channel and the receiver for the DTV system to confirm the feasibility of the proposed one for the commercial service.     

Impact of 2D and 3D display watching on EEG power spectra: A standardized low-resolution tomography (sLORETA) study

We investigated whether watching two-dimensional television (2DTV) or three-dimensional television (3DTV) resulted in differences in the brain’s processing of sensory information. We divided 25 participants into 2DTV (n = 13) and 3DTV (n = 12) groups. Participants watched 2DTV or 3DTV for 1, 2, or 3 h on different days. Before and at the end of each session, electroencephalography (EEG) was recorded for 10 min. The Simulation Sickness Questionnaire (SSQ) and the Visual Analog Scale (VAS) were used to assess general discomfort before and after watching. Each frequency band of the resting EEG was transformed into a standardized low-resolution electromagnetic tomographic (sLORETA) image. In the 2DTV group, 2 h of watching increased theta power in the central cortex and 3 h of watching increased beta power in the occipital cortex. In the 3DTV group, 3 h of watching increased delta power in the parahippocampal gyrus and middle frontal cortex. Theta power was significantly higher in the insular cortex after 3 h of 3DTV than after 3 h of 2DTV. SSQ scores were significantly higher after 1 h of 2DTV than after 1 h of 3DTV. Watching 2DTV vs. 3DTV triggered different time-dependent activity patterns. Watching 3DTV for 3 h increased slow-wave activity in the prefrontal cortex, while watching 2DTV increased fast-wave activity in the occipitoparietal cortex. Up to 2 h of 3DTV watching did not cause major changes in fatigue or EEG activity compared with 2DTV. Our findings promise to be useful in designing safety guidelines for watching 3DTV.     

LED电视在3D模式下的视觉健康舒适度测试研究

通过客观量测人眼观视时的各项视觉生理指标,并将各项指标嵌入人眼健康舒适度评价模型进行分析运算的方式,经由180人次的人因实验,从视觉健康舒适度等方面对3款主流品牌的LED电视样机进行了较为详细的测试与评价。     

Java3D在网络三维游戏设计中的应用探讨

随着网络技术、虚拟现实技术的迅猛发展、人们生活娱乐水平的提高,近几年三维网络游戏成为热门焦点.现介绍了三维网络游戏的发展现状,选择Java3D的优点并举例说明,也简要说明了它的一些不足之处.     

基于分布式两坐标雷达网络的目标三维跟踪算法

针对目前的航空管理和作战指挥系统的需求,该文提出一种基于分布式两坐标(2D)雷达网络的目标3维跟踪算法。首先,该文从集中式框架下融合中心的广义量测方程出发,推导了融合中心的更新方程。而后,将更新方程中的量测用各部雷达的局部跟踪信息来代替,并由此得出目标3维状态的估计。从推导过程可知,该文所提算法是量测扩维的集中式融合算法通过矩阵变换直接得到的,只是变换过程中对单雷达跟踪模型进行了近似,因此是次优的。最后,蒙特卡罗仿真实验表明,该算法收敛速度很快,且跟踪精度很高,可以满足实际需求。     

Vertical-type 3D/Quasi-2D n-p Heterojunction Perovskite Photodetector

This research demonstrates a state-of-the-art vertical-transport photodetector with an n-type 3D MAPbI₃/p-type quasi-2D (Q-2D) BA₂MA₂Pb₃I₁₀ perovskite heterojunction. This structure introduces a ≈0.6 V built-in electric field at the n-p junction that greatly improves the characteristics of the perovskite photodetector, and the presence of Q-2D perovskite on the surface improves the life. The electrical polarities of the 3D and the Q-2D perovskite layers are simply controlled by self-constituent doping, making clearly defined n-p characteristics. Doctor-blade coating is used to fabricate the photodetector with a large area. The Q-2D materials with highly oriented (040) Q-2D (n = 2,3) planes are near the surface, and the (111) preferred planes mixed with high index Q-2D materials (n = 4,5) are found near the 3D/Q-2D interface. The stacking and interface are beneficial for carrier extraction and transport, yielding an external quantum efficiency of 77.9%, a carrier lifetime long as 295.7 ns, and a responsibility of 0.41 A W⁻¹. A low dark current density of 6.2 × 10⁻⁷ mA cm⁻² and a high detectivity of 2.82 × 10¹³ Jones are obtained. Rise time and fall time are fast as 1.33 and 10.1 µs, respectively. The results show the application potential of 3D/Q-2D n-p junction perovskite photodetectors.     

大视角二维/三维彩虹全息标识记录

提出了一种记录透射标识二维／三维彩虹全息图的新方法，它直接用散射狭缝光照明二维透射标识，将透射光记录为主全息图；主全息图可按普通二步彩虹一样进行二维／三维的分色、分层次记录，既保持了普通二步彩虹全息的分色、分层次的效果，又突破了普通主全息图面积和长度对再现像亮度和视角的限制，达到大视角、高亮度的效果；对光路的可行性和设置参数进行了详细的分析和讨论，相应的实验得到了满意的结果。     

Multi-layer fusion network for blind stereoscopic 3D visual quality prediction

Stereoscopic 3D (S3D) visual quality prediction (VQP) is used to predict human perception of visual quality for S3D images accurately and automatically. Unlike that of 2D VQP, the quality prediction of S3D images is more difficult owing to complex binocular vision mechanisms. In this study, inspired by the binocular fusion and competition of the binocular visual system (BVS), we designed a blind deep visual quality predictor for S3D images. The proposed predictor is a multi-layer fusion network that fuses different levels of features. The left- and right-view sub-networks use the same structure and parameters. The weights and qualities for the left- and right-view patches of S3D images can be predicted. Furthermore, training patches with more saliency information can improve the accuracy of prediction results, which also make the predictor more robust. The LIVE 3D Phase I and II datasets were used to evaluate the proposed predictor. The results demonstrate that the performance of the proposed predictor surpasses most existing predictors on both asymmetrically and symmetrically distorted S3D images.     

2D/3D图像配准中的相似性测度和优化算法

在手术引导治疗中,2D/3D图像配准能辅助医生准确定位病人病灶,而准确的配准涉及相似性测度和优化算法等众多方面。为了研究相似性测度和优化算法对2D/3D图像刚性配准的影响,本文结合6种相似性测度和4种优化方法在配准"金标准"数据上进行了2D/3D图像配准实验,并从配准成功率、平均迭代次数和平均配准时间三个方面对配准结果进行了对比研究。实验结果表明,以模式强度为相似性测度,用Powell方法进行优化搜索是最佳配准组合。并且,在不改变相似性测度条件下,Powell方法是所用优化方法中配准效果最好的优化方法。     

PTN网络架构中L2转L3设置方案

分组传送网(PTN)凭借其技术优势已成为传送网络的主流技术之一.初期的PTN网络架构中L2/L3设备设置于核心层,从而存在网络安全性较差和系统承载能力较弱两大难题.结合中国移动网络现状,提出L2/L3设备设置于汇聚层的新型PTN网络架构,并将该架构与初期的PTN网络架构进行对比.结果表明,L2/L3设备设置于汇聚层的PTN网络架构在安全性和高效性上表现更优.     

Efficient Blue Perovskite Light‐Emitting Diodes Boosted by 2D/3D Energy Cascade Channels

Lead halide perovskite, as an emerging semiconductor, provides a fire‐new opportunity for high‐definition display and solid‐state lighting. Earthshaking improvements are implemented in green, red, and near‐infrared perovskite light‐emitting diodes (PeLEDs). However, blue PeLEDs are still far behind in performance, which restricts the development of PeLEDs in practical applications. Herein, a facile energy cascade channel strategy via one‐step self‐organized and controllable 2D/3D perovskite preparation by introducing guanidine hydrobromide (GABr) is developed that greatly improves the efficiency of blue PeLEDs. The 2D/3D perovskite structure boosts the energy cascade to induce energy transfer from the wide into the narrow bandgap domains and inhibit free charge diffusion, which increases the density of electrons and holes, and enhances the radiative recombination. Profiting from this energy cascade channels, the external quantum efficiency of blue PeLEDs, emitting at 492 nm, is considerably enhanced from 1.5% of initial blue device to 8.2%. In addition, device operating stability under ambient conditions is also improved by 2.6‐fold. The one‐step self‐organized 2D/3D hybrid perovskites induced by GABr pave a new and simple route toward high‐performance blue emission PeLEDs.     

Emulation-based transient thermal modeling of 2D/3D systems-on-chip with active cooling

State-of-the-art devices in the consumer electronics market are relying more and more on Multi-Processor Systems-On-Chip (MPSoCs) as an efficient solution to meet their multiple design constrains, such as low cost, low power consumption, high performance and short time-to-market. In fact, as technology scales down, logic density and power density increase, generating hot spots that seriously affect the MPSoC performance and can physically damage the final system behavior. Moreover, forthcoming three-dimensional (3D) MPSoCs can achieve higher system integration density, but the aforementioned thermal problems are seriously aggravated. Thus, new thermal exploration tools are needed to study the temperature variation effects inside 3D MPSoCs. In this paper, we present a novel approach for fast transient thermal modeling and analysis of 3D MPSoCs with active (liquid) cooling solutions, while capturing the hardware-software interaction. In order to preserve both accuracy and speed, we propose a close-loop framework that combines the use of Field Programmable Gate Arrays (FPGAs) to emulate the hardware components of 2D/3D MPSoC platforms with a highly optimized thermal simulator, which uses an RC-based linear thermal model to analyze the liquid flow. The proposed framework offers speed-ups of more than three orders of magnitude when compared to cycle-accurate 3D MPSoC thermal simulators. Thus, this approach enables MPSoC designers to validate different hardware- and software-based 3D thermal management policies in real-time, and while running real-life applications, including liquid cooling injection control.     

2D/2D 1T‐MoS2/Ti3C2 MXene Heterostructure with Excellent Supercapacitor Performance

2D/2D heterostructures can combine the collective advantages of each 2D material and even show improved properties from synergistic effects. 2D Transition metal carbide Ti₃C₂ MXene and 2D 1T‐MoS₂ have emerged as attractive prototypes in electrochemistry due to their rich properties. Construction of these two 2D materials, as well as investigation about synergistic effects, is absent due to the instability of 1T‐MoS₂. Here, 3D interconnected networks of 1T‐MoS₂/Ti₃C₂ MXene heterostructure are constructed by magneto‐hydrothermal synthesis, and the electrochemical storage mechanisms are investigated. Improved extra capacitance is observed due to enlarged ion storage space from a synergistically interplayed effect in 3D interconnected networks. Outstanding rate performance is realized because of ultrafast electron transport originating from Ti₃C₂ MXene. This work provides an archetype to realize excellent electrochemical properties in 2D/2D heterostructures.     

In Situ Fabrication of Highly Luminescent Bifunctional Amino Acid Crosslinked 2D/3D NH3C4H9COO(CH3NH3PbBr3)n Perovskite Films

The perovskite quantum dots are usually synthesized by solution chemistry and then fabricated into film for device application with some extra process. Here it is reported for the first time to in situ formation of a crosslinked 2D/3D NH₃C₄H₉COO(CH₃NH₃) _n Pb_n Br_3n perovskite planar films with controllable quantum confine via bifunctional amino acid crosslinkage, which is comparable to the solution chemistry synthesized CH₃NH₃PbBr₃ quantum dots. These atomic layer controllable perovskite films are facilely fabricated and tuned by addition of bi‐functional 5‐aminovaleric acid (Ava) of NH₂C₄H₉COOH into regular (CH₃NH₃)PbBr₃ (MAPbBr₃) perovskite precursor solutions. Both the NH₃⁺ and the COO^? groups of the zwitterionic amino acid are proposed to crosslink the atomic layer MAPbBr₃ units via Pb? COO bond and ion bond between NH₃⁺ and [PbX₆] unit. The characterizations by atomic force microscopy, scanning electron microscopy, Raman, and photoluminescence spectroscopy confirm a successful fabrication of ultrasmooth and stable film with tunable optical properties. The bifunctional crosslinked 2D/3D Ava(MAPbBr₃)_n perovskite films with controllable quantum confine would serve as distinct and promising materials for optical and optoelectronic applications.     

二维图像转三维图像的立体成像系统的测试标准

本文具体介绍了一种将视频二维图像转换为兰维图像的立体成像系统的测试标准.     

3D Deformable Convolution Temporal Reasoning network for action recognition

Modeling and reasoning of the interactions between multiple entities (actors and objects) are beneficial for the action recognition task. In this paper, we propose a 3D Deformable Convolution Temporal Reasoning (DCTR) network to model and reason about the latent relationship dependencies between different entities in videos. The proposed DCTR network consists of a spatial modeling module and a temporal reasoning module. The spatial modeling module uses 3D deformable convolution to capture relationship dependencies between different entities in the same frame, while the temporal reasoning module uses Conv-LSTM to reason about the changes of multiple entity relationship dependencies in the temporal dimension. Experiments on the Moments-in-Time dataset, UCF101 dataset and HMDB51 dataset demonstrate that the proposed method outperforms several state-of-the-art methods.     

基于X3D／VRML的三维虚拟展馆定制系统的研究

为了满足用户对虚拟会展展馆个性化的需要,提出了如何建立基于X3D/VRML虚拟现实技术的三维虚拟展馆定制系统,详细叙述了交互定制、碰撞检测和数据库处理的关键技术.该系统具有较好的实用性,既为真实展馆的定制提供仿真的平台,又为如何建立虚拟展馆提供了范例.     

3D/2D Perovskite Single Crystals Heterojunction for Suppressed Ions Migration in Hard X-Ray Detection

Halide perovskites exhibit diverse properties depending on their compositions. However, integrating desired properties into one material is still challenging. Here, a facile solution-processed epitaxial growth method to grow 2D perovskite single crystal on top of 3D perovskite single crystal, which can passivate the surface defects for improved device performance is reported. Short formamidine (FA⁺) ions are replaced by long organic cations, which can fully align and cover the single crystal surface to prevent the ions migration or short FA⁺ ions volatilization. The thickness of epitaxial layer can be finely adjusted by controlling the growth time. The defect density of single crystals heterojunction is only 3.18 × 10⁹ cm⁻³, and the carrier mobility is 80.43 cm² V⁻¹ s⁻¹, which is greater than that of the control 3D perovskite single crystal. This study for the first time realized large area 3D/2D perovskite single crystals heterojunction, which suppressed ions migration and exhibited advanced performance in hard X-rays detection applications. This strategy also provides a way to grow large area 2D perovskite single crystal from solution processes.