轻型大视场自由曲面棱镜头盔显示器的设计

轻型大视场头盔显示器(HMD)在虚拟现实、增强现实、军事和反恐等领域具有广阔的应用前景。传统的目镜结构形式难以满足头盔显示器对系统视场、体积和重量的苛刻要求。通过采用自由曲面(FFS)棱镜实现了大视场轻型头盔显示器目视光学系统，讨论了FFS头盔显示系统的设计方法并给出了设计结果。     

新技术的结晶:头盔显示器

头盔显示器（Ｈｅｌｍｅｔ－Ｍｏｕｎｔｅｄ Ｄｉｓｐｌａｙｓ，ＨＭＤ）由１９６８年哈佛大学的Ｉｖａｎ Ｓｕｔｈｅｒｌａｎｄ首先提出，并设计出应用ＣＲＴ的名为达摩克里斯之剑的头盔显示器。经过３０年的发展，头盔显示器取得了巨大的进步和广泛的应用。特别是在微型液晶显示器、虚拟现实（ＶＲ）、袖珍计算机、可视移动电话以及现代数字化部队的装备中的逐渐普及，使得头盔显示器在这些领域中占据了重要的地位。 头盔显示器应用 无论是要求在现实世界的视场上同时看到需要的数据，还是要体验视觉图像变化时全身心投入的临场感，模拟训…     

终端设备与显示设备

SPIE-Vol.4021 0217840SPIE 会议录,卷4021:头盔及头戴式显示器=Proceed-ings of SPIE,Vol.4021:Helmet-and head-mounted dis-plays V[会,英]/SPIE-The International Society for Op-tical Engineering.—366P.(E)本会议录收集了在奥兰多召开的头盔与头戴式显示器会议上发表的36篇论文,内容涉及非战场用头戴式显示器技术,直升机驾驶员头戴式邻近视觉显示,微型平板显示技术,虚拟现实飞行训练器,战场车辆可视化系统。     

头盔显示器图像源技术研究

图像源技术在头盔显示器系统中占有重要的地位。简述了图像源技术的发展及透视式有源矩阵液晶显示器，详述了新出现的透反式液晶显示技术，及其在头盔显示器研究中具有的良好的应用前景。     

模拟现实显示

模拟现实显示贾正根模拟现实显示器（Ｖｉｒｔｕａｌ－Ｒｅａｄｉｔｙｆａｓｐｌａｙ）缩写或ＶＲＤ。也有人称为虚拟现实显示器。它是一种宽视场、高亮度、高分辨率头盔显示器。由于它视场竞，也称为模拟全景显示器（ＶｉｒｔｕａｌＰａｎｏｒａｍｉｃＤｉｓｐｌａｙ—Ｖ...     

头盔显示技术的发展

主要介绍机载头盔显示技术的发展情况。重点论述头盔显示器必须具备的功能和要素，并且对机载头盔显示器设计中涉及到的问题进行了讨论。最后给出了目前国际上在研的几种比较先进的头盔显示器的例子。     

头盔显示器的关键技术及有关设计问题综述

头盔显示器可以提高驾驶员的态势感知能力，红外传感器提供的信息，使驾驶员的态势感知能力大大加强，头盔显示器提供的红外图像，使恶劣的天气和黑夜不再成为驾驶员作战的障碍，概述了头盔显示器的发展过程和关键技术，介绍了当前空军用头盔显示器的技术问题，解决方法，设计示例。     

新型彩色LCOS头盔微显示器光学系统

通过对实像显示技术和虚像显示技术的区别的简要介绍,阐述了头盔微显示器在未来战场上对数字化士兵的重要作用以及头盔微显示技术的研发意义。通过对LCOS头盔微显示器显示原理的阐述,着重介绍了一种新型彩色LCOS头盔微显示器整个光学系统设计方面的最新研究成果。     

头盔显示器图像源技术研究

图像源技术在头盔显示器系统中占有重要的地位。简述了图像源技术的发展及透视式有源矩阵液晶显示器,详述了新出现的透反式液晶显示技术,及其在头盔显示器研究中具有的良好的应用前景。     

全息头盔显示器的光学设计

与平视显示器相比,头盔显示器的突出优点是具有特别大的视场。但是,使用普通光学系统的头盔显示器,在显示亮度和体积重量方面还不能完全令人满意。为了进一步改进头盔显示器的现有技术性能,本文提出几个适用于头盔显示器的全息光学系统方案,并分析了它们的长短利弊以供对比择优。对于普遍关心且涉及方案可行性的全息光学元件像差校正问题,本文予以概括论述以供制造时参考。     

大视场虚拟现实头戴显示器光学结构设计

为了满足用户对虚拟现实头戴显示器大视场和高分辨率的需求,采用逆向设计方法,通过理论计算与软件仿真,设计了一种同轴大视场虚拟现实型头戴显示器的光学结构。结果表明,每个通道采用3片非球面透镜,全视场角为90°,出瞳直径为8mm,出瞳距离为13mm,在奈奎斯特频率10.58lp/mm处调制传递函数大于0.3,最大畸变为6.1%;与参考文献相比,此结构分辨率高、畸变小、像差平衡合理。该设计为优化大视场头戴显示器的光学结构提供了参考。     

沉浸式头戴显示器光学系统设计

为了满足虚拟现实头戴显示器大视场、大出瞳和高成像质量等要求,采用非球面透镜设计了1种3片式虚拟现实头戴显示器光学系统,对光学系统进行了公差分析。结果表明,光学系统的平均调制传递函数(MTF)值均满足传递函数的要求;系统视场角为90°、出瞳直径为8mm、系统重量为33.67g、总长小于60mm、频率为9.31lp/mm时的MTF值均优于0.272,最大畸变为8.17%,最大垂轴色差为36.2μm,小于一个像素尺寸;与已有研究相比,增加了视场角、出瞳直径和出瞳距离等参量的信息,提高了成像质量。该研究为沉浸式头戴显示器的光学设计提供了参考。     

基于移动式全景成像的增强现实关键技术研究

将全景成像和单自由度移动机器人的关键技术应用到增强现实领域中,解决了当图像采集装置与头盔显示器分离并且图像采集装置在场景中移动情况下的增强现实系统的技术难点。建立完整的基于全景成像的增强现实系统,将单自由度移动机器人引入增强现实领域,并提出图像共享的概念。实验表明,全景成像方法对于亮度差异较大图像的拼接效果良好,适宜于室外复杂环境的图像拼接,全景图像的局部增强显示效果良好。     

Expanded Exit-Pupil Holographic Head-Mounted Display With High-Speed Digital Micromirror Device

Recently, techniques involving head-mounted displays (HMDs) have attracted much attention from academia and industry owing to the increased demand for virtual reality and augmented reality applications. Because HMDs are positioned near to users’ eyes, it is important to solve the accommodation-vergence conflict problem to prevent dizziness. Therefore, holography is considered ideal for implementing HMDs. However, within the Nyquist region, the accommodation effect is limited by the space-bandwidth-product of the signal, which is determined by the sampling number of spatial light modulators. In addition, information about the angular spectrum is duplicated over the Fourier domain, and it is necessary to filter out the redundancy. The size of the exit-pupil of the HMD is limited by the Nyquist sampling theory. We newly propose a holographic HMD with an expanded exit-pupil over the Nyquist region by using the time-multiplexing method, and the accommodation effect is enhanced. We realize time-multiplexing by synchronizing a high-speed digital micromirror device and a liquid-crystal shutter array. We also demonstrate the accommodation effect experimentally.     

虚拟现实技术在美军模拟训练中的应用现状及发展

通过对虚拟现实技术概念、特征及相关技术的介绍,引出了虚拟现实技术在各个领城尤其是军事领城的应用;然后从构建虚拟战场、单兵训练、异地同环境作战训练、军事指挥人员训练、提高指挥决策能力、武器装备研制及信息网络虚拟战等7个方面,重点介绍了虚拟现实技术在美军模拟训练中的应用现状;最后探讨了未来美军应用虚拟现实技术在模拟训练方面...     

基于ＯpenＣＶ技术的复合手势特征识别算法

手势特征识别作为图像特征识别的一个重要研究方向,在很多了领域都有着非常广阔的应用前景,尤其是随着全息投影技术的发展,虚拟与现实的应用逐渐走入了人们的视野并得到了初步应用.利用OpenCV技术,针对手势特征识别提出了全新的复合识别算法.经过验证,该算法具有很高的识别率并且拥有良好旋转不变性,在今后军事指挥决策系统中具有良好的应用前景.     

Using EMG to anticipate head motion for virtual-environment applications

In virtual environment (VE) applications, where virtual objects are presented in a see-through head-mounted display, virtual images must be continuously stabilized in space in response to user's head motion. Time delays in head-motion compensation cause virtual objects to "swim" around instead of being stable in space which results in misalignment errors when overlaying virtual and real objects. Visual update delays are a critical technical obstacle for implementing head-mounted displays in applications such as battlefield simulation/training, telerobotics, and telemedicine. Head motion is currently measurable by a head-mounted 6-degrees-of-freedom inertial measurement unit. However, even given this information, overall VE-system latencies cannot be reduced under about 25 ms. We present a novel approach to eliminating latencies, which is premised on the fact that myoelectric signals from a muscle precede its exertion of force, thereby limb or head acceleration. We thus suggest utilizing neck-muscles' myoelectric signals to anticipate head motion. We trained a neural network to map such signals onto equivalent time-advanced inertial outputs. The resulting network can achieve time advances of up to 70 ms.     

Augmented System for Immersive 3D Expansion and Interaction

In the field of augmented reality technologies, commercial optical see‐through‐type wearable displays have difficulty providing immersive visual experiences, because users perceive different depths between virtual views on display surfaces and see‐through views to the real world. Many cases of augmented reality applications have adopted eyeglasses‐type displays (EGDs) for visualizing simple 2D information, or video see‐through‐type displays for minimizing virtual‐ and real‐scene mismatch errors. In this paper, we introduce an innovative optical see‐through‐type wearable display hardware, called an EGD. In contrast to common head‐mounted displays, which are intended for a wide field of view, our EGD provides more comfortable visual feedback at close range. Users of an EGD device can accurately manipulate close‐range virtual objects and expand their view to distant real environments. To verify the feasibility of the EGD technology, subject‐based experiments and analysis are performed. The analysis results and EGD‐related application examples show that EGD is useful for visually expanding immersive 3D augmented environments consisting of multiple displays.     

Current and future applications of virtual reality for medicine

Virtual reality is just emerging as an accepted scientific discipline for medicine. The majority of near-term applications are in the area of surgical planning, interoperative navigation, and surgical simulations. Its use in rehabilitative medicine and psychiatry has made significant progress. The immediate future holds promise for virtual endoscopy, which may replace standard endoscopic procedures for diagnostic screening. Viewing of these virtual images may be with head-mounted displays or true suspended holograms. The most highly developed area is in surgical simulations. Current generations are approaching photorealistic representation of the anatomy, while measurement science is providing physical tissue properties and physiologic parameters. The types of simulations range from “needle-based” procedures, such as standard intravenous insertion, central venous placement catheter, and chest-tube insertion to more sophisticated simulations of full surgical procedures like laparoscopic cholecystectomy or hysteroscopic resection of interuterine myoma. In addition, haptic input devices are providing the sense of touch to the procedures. Soon there will be patient-specific models derived from computed tomography or magnetic resonance imaging scans that will permit a surgeon to practice a delicate surgical procedure on the patient's specific virtual anatomy before actually performing the procedure on the patient