柱透镜光栅3D显示器的视差范围与立体观看视疲劳的关系

过大的视差取值是产生柱透镜光栅3D显示器立体观看视疲劳的主要因素之一。基于人眼瞳孔直径随着立体观看视疲劳程度的增加而递增这一生理机理,本文建立了一个瞳孔直径的测量装置,可在观看者观看立体图像的同时记录观看者的瞳孔变化,从而客观评价观看者的立体观看视疲劳程度,并通过与观看者的主观评价相结合,得出不同视差大小下的立体观看视疲劳程度。实验结果表明,当视差在-0.2°～0.2°范围内时,观看者没有明显的立体观看视疲劳,可将该范围确定为观看舒适的视差范围。     

基于视觉重要区域的立体图像视觉舒适度客观评价方法

先进的立体视频技术能给观众带来深度感和沉浸感,但也容易使人产生视觉疲劳,造成观看体验质量的下降,因此,如何对立体视频/图像的视觉舒适度进行有效评价是目前的研究难点。该文提出一种基于视觉重要区域的立体图像视觉舒适度客观评价模型,该模型主要包括3个部分:(1)利用图像显著图和视差图像得到立体图像视觉重要区域;(2)提取视觉重要区域的视差幅度特征、视差梯度边缘特征以及空间频率特征,作为反映立体图像视觉舒适度的感知特征信息;(3)通过支持向量回归建立特征信息与立体图像舒适度平均主观评分值的关系,预测得到立体图像视觉舒适度的客观评价值。实验结果表明,与现有的方法相比较,在相同的立体图像测试库上,采用该文提出的客观评价模型可以获得更好的评价性能。     

一种3D视频中立体字幕叠加技术

运用3D字幕视差与背景景深的对应关系,基于立体视觉的双目视差原理叠加3D字幕,实现了基于三维图像内容的景深叠加3D字幕的系统.该立体字幕叠加方法具有简单、稳健等特点,缓解了观看时的视觉疲劳问题,使观众更舒适地观看立体图像和字幕.     

一种基于用户关注的立体图像舒适度评价算法

近年来,立体电视和立体电影的发展掀起了一股“3D”热潮.要让观众享受到高质量的立体内容,首先要解决人们在观看立体视频图像时的不舒适感.以立体图像的视差因素为切入点,结合人眼关注模型,设计并实现了一种立体图像舒适度的客观评价方法.该方法根据人造立体图像的主观实验评价结果,建立了视差—舒适度模型,同时结合图像显著信息,对立体图像的舒适度进行了预测.对比主观评价结果,所提出的立体图像舒适度客观评价方法所获取的评价结果与人眼感受具有较好的一致性.     

3D电视视差舒适度客观评价

视差是双目立体视觉的重要研究方向,也是影响人眼观看3D电视舒适度的重要因素,本文阐述了双目立体视觉和视差的概念、约束条件,介绍了3D电视视频图像质量评价的方法、发展以及相关标准,最后分析视差舒适度客观评价的相关算法,并通过实验对比各种算法的提取精度和效果,设计和实现3D电视视差舒适度客观评价软件。     

立体图像对校正技术在三维显示中的应用

基于相机阵列的立体视差图像获取是3D立体显示技术的关键步骤之一,它为立体显示提供了丰富多彩的图像源;由于平行摆放的阵列相机拍摄得到的视差图像没有梯形失真和垂直视差,经3D显示设备后不会使观众产生视疲劳,因此,人们在视差图像获取时常采用时平行摆放的相机阵列.然而,在实际的操作中是很难达到这样理想的条件;本文针对常用的非平行摆放的双相机,经由图像校正的处理方法,来获得相同条件下平行式相机拍摄的效果;通过实验表明,该方案简单易行,效果良好,经3D自由立体显示后,观看的舒适度得到了提高.     

视差式立体信息采集、感知几何模型及舒适观看区研究综述

近年来,立体影视产业蓬勃发展,基于视差的立体成像技术成为市场主流.但是,基于视差的立体成像技术存在深度畸变、视觉不舒适等问题.针对这些问题,本文研究了立体视频系统几何模型与舒适观看区.首先,总结并比较了立体采集系统的各种配置模式;接着讨论了平移式立体系统中拍摄空间到感知空间的映射关系,即畸变模型,并用形状、深度畸变因子解释了木偶剧效应和纸板效应;然后分析了舒适观看区,对其三种定义做了比较,并基于国际上普遍采用的1°视差计算得出了舒适观看区域的几何范围;最后,本文将畸变模型和舒适观看区相关联,总结了立体图像拍摄应遵守的基本准则.     

视差与空间频率对自由立体显示器观看舒适度的影响

观看舒适度是评价自由立体显示器性能的重要指标。立体图像的视差和空间频率影响人眼的感知深度,从而对观看舒适度有重要作用。本文采用3DS MAX三维建模软件和Photoshop图像处理软件得到不同视差和空间频率的立体图像,通过观看舒适度的客观度量结合主观评价确定视差及空间频率与观看舒适度的关系,得出观看舒适度较高时的视差范围和与之相对应的空间频率范围。实验表明,立体图像低空间频率所致的模糊可以增加观看舒适度。     

立体图像生成的视差控制

获取合适的视差信息是立体图像得到舒适观看的重要条件。为达到上述目的,提出了一种立体图像视差检测和控制方案。首先分析2种人眼视觉生理学限制的数学模型,并结合人眼跟踪技术获取生理视差容限。然后使用OpenGL图像绘制引擎获取显示场景的极值深度信息,进而计算出画面视差范围。最终通过比对虚拟场景的视差与观察者的生理视差容限,确定场景视差正确性并加以修正。实验证明,方案可以实时地进行视差控制,为立体图像生成提供了可靠依据。     

一种基于用户关注模型的立体图像舒适度客观评价方法

近年来,立体电视和立体电影的发展掀起了一股“3D”热潮。要让观众享受到高质量的立体内容,首先要解决人们在观看立体视频图像时的不舒适感。本文以立体图像的视差因素为切入点,结合人眼关注模型,设计了并实现了一种立体图像舒适度的客观评价方法。该方法根据人造立体图像的主观实验评价结果,建立了视差——舒适度模型,同时结合图像显著信息,对立体图像的舒适度进行了预测。对比主观评价结果,本文实现的所提出的立体图像舒适度客观评价方法所获取的评价结果与人眼感受具有较好的一致性。     

基于双目能量模型的立体图像质量客观评价方法

立体图像的深度感知取决于双目差距,基础视觉皮层的差距调谐细胞在感知立体深度的过程中起着关键作用.单只眼睛感知的图像信息被单目简单细胞接收之后传入双目简单细胞进行处理,继而被送入复杂细胞进行综合,得到基础视觉皮层对于一幅立体图像的能量响应.用数学模型来仿真简单的以及复杂的细胞对于双目差距的响应,并通过双目能量模型的计算达到评价彩色立体图像的目的.实验结果表明,双目能量模型的评价结果与立体图像的主观评价值具有较高的一致性.     

光栅3D显示视疲劳与视功能参数的关系

观看光栅3D显示的机理和人眼视觉生理存在矛盾 ,观看时间稍长将引起头痛、眼胀、复视等视疲 劳症状,选择恰当的生理指标对视疲劳进行客观评价对其预防和消除具有重要意义。本研究 探讨观看光栅 3D显示对双眼视功能参数的影响。通过视觉检查筛选出24名被试者,并随机分成两组进行 30分钟持续观 看光栅3D显示2D视频和3D视频的实验。在观看实验前后分别对被试者进行视功能参数—双眼 融合范围、 AC/A值和CFF值的测量,并完成视疲劳和视觉诱导晕动症主观问卷。实验验证了融合范围 、AC/A值和 CFF值都随着视疲劳和VIMS的加剧而降低。2D组观看前后融合范围无差异,3D组观看前 后融合范围有 显著区别,而2D组和3D组的AC/A值和CFF值在观看前后都有显著差异。3D观看前后融合 范围、AC/A 值、CFF值降低幅度均比2D更大。实验结果表明,3D比2D造成了更严重的视疲劳和VIMS ,而晕动症是导致观看光栅3D显示不舒适的主要原因。     

Repeated vergence adaptation causes the decline of visual functions in watching stereoscopic television

To evaluate visual fatigue when viewing stereoscopic TV, a technology expected to become the broadcasting display system of the future. Wide public acceptance of stereoscopic TV awaits resolution of many issues, including visual fatigue on viewing TV images. Visual fatigue was induced using a visual function simulator, consisting of prism and lens optical systems, while viewing stereoscopic TV. We assessed subject visual fatigue through subjective reports of symptoms and by the changes in visual functions. These functions included: viewer B [Js fusional break point, recovery point, accommodation step response, and visual evoked cortical potentials (VECP)]. Significant changes of some visual functions were found after watching simulated stereoscopic TV when the vergence load was heavy or when it changed over time; relative vergence limits decreased and the latency of VECP increased after watching, reflecting visual fatigue. After subjects rested, relative vergence limits recovered to pre-viewing levels. Our findings lead us to conclude that, aside from excessive horizontal binocular parallax, discontinuous changes in parallax is also a major factor that contributes to visual fatigue in the viewing of stereoscopic images. It also causes a decreased range of relative vergence, accommodation response, and a delay in the P100 latency of VECP.     

A depth perception and visual comfort guided computational model for stereoscopic 3D visual saliency

With the emerging development of three-dimensional (3D) related technologies, 3D visual saliency modeling is becoming particularly important and challenging. This paper presents a new depth perception and visual comfort guided saliency computational model for stereoscopic 3D images. The prominent advantage of the proposed model is that we incorporate the influence of depth perception and visual comfort on 3D visual saliency computation. The proposed saliency model is composed of three components: 2D image saliency, depth saliency and visual comfort based saliency. In the model, color saliency, texture saliency and spatial compactness are computed respectively and fused to derive 2D image saliency. Global disparity contrast is considered to compute depth saliency. Particularly, we train a visual comfort prediction function to distinguish stereoscopic image pair as high comfortable stereo viewing (HCSV) or low comfortable stereo viewing (LCSV), and devise different computational rules to generate a visual comfort based saliency map. The final 3D saliency map is obtained by using a linear combination and enhanced by a “saliency-center bias” model. Experimental results show that the proposed 3D saliency model outperforms the state-of-the-art models on predicting human eye fixations and visual comfort assessment.     

Hierarchical visual comfort assessment for stereoscopic image retargeting

Stereoscopic Image Retargeting (SIR) has made it possible for the popularity of 3D application. Meanwhile, the adjustments brought to images may affect the visual comfort when enjoying 3D service. While for SIR, previous Visual Comfort Assessment (VCA) methods often cannot perform well, because they only analyze the influence of disparity on discomfort and do not take into account the effects from the unique and complex distortions of SIR. In this paper, we propose a Hierarchical Visual Comfort Assessment (Hi-VCA) scheme for SIR, considering hybrid distortions including structure, information, semantic distortions usually occurring in retargeting, and binocular incongruity existing in stereoscopic multimedia. Specifically, we first propose valid Local-SSIM and Dual Natural Scene Statistics (D-NSS) features to measure structural distortion and information loss. Considering disparity adjustments may brought by SIR, we design the binocular incongruity measurement by analyzing various binocular anomaly perception mechanisms of HVS. Finally, CNN-based feature is utilized to ensure the correct delivery of semantic information. Each measurement is complementary in describing visual comfort degradation and they are further aggregated. Extensive experiment results on published SIR database SIRD and two ordinary databases IEEE-SA and NBU 3D-VCA, demonstrate Hi-VCA has superior performance by better handling hybrid distortions compared to state-of-the-art schemes.     

Three-dimensional imaging methods based on multiview images

Three-dimensional imaging methods, based on parallaxes as their depth cues, can be classified into the stereoscopic providing binocular parallax only, and multiview providing both binocular and motion parallaxes. In these methods, the parallaxes are provided by creating a viewing zone with use of either a special optical eyeglasses or a special optical plate as their viewing zone-forming optics. For the stereoscopic image generations, either the eyeglasses or the optical plate can be employed, but for the multiview the optical plate or the eyeglasses with a tracking device. The stereoscopic image pair and the multiview images are presented either simultaneously or as a time sequence with use of projectors or display panels. For the case of multiview images, they can also be presented as two images at a time according to the viewer's movements. The presence of the viewing zone-forming optics often causes undesirable problems, such as appearance of moire/spl acute/ fringes, image quality deterioration, depth reversion, limiting viewing regions, low image brightness, image blurring, and inconveniences of wearing.     

液晶荧幕中卷动文件对视觉绩效与视觉不适之研究

汽车液晶荧幕愈来愈广泛,其中文件浏览工具为一种应用范围.浏览文字或图片资讯时,大部分软件都提供可以缩放荧幕文件大小与卷动文字页面这些功能.然而,有时持续性的跳动对视觉产生很大影响,眼睛随著快速的卷动很容易造成疲劳与不适.在快速卷动下,文字太小,不容易辨识,文字太大,也容易产生模糊.本研究利用阅读文件来了解卷轴速度与缩放比例对视觉绩效与疲劳之影响.结果得知缩放比例对于视觉疲劳有显著影响,因此,文件浏览工具的设计可以改善视觉不适的现象.     

自由立体显示器的光学性能测量与研究

为了评价自由立体显示器的光学性能,以八视点狭缝光栅自由立体显示器为例,针对不同的视点图像,测量了不同视角下的亮度值与色度值,研究自由立体显示器的光学性能,其光学性能包括自由立体显示器的最佳观看位置、串扰、可视范围、亮度均匀性、色度均匀性和莫尔条纹。结果表明,这种测量及分析方法实现了对多视点立体显示器光学性能的定量评估,增强了评估立体显示器性能的客观性,对自由立体显示器的设计具有指导意义。