A wide view auto‐stereoscopic 3D display with an eye‐tracking system for enhanced horizontal viewing position and viewing distance

This paper describes the development of auto‐stereoscopic three‐dimensional (3D) display with an eye‐tracking system for not only the X‐axis (right–left) and Y‐axis (up–down) plane directions but also the Z‐axis (forward–backward) direction. In the past, the eye‐tracking 3D system for the XY‐axes plane directions that we had developed had a narrow 3D viewing space in the Z‐axis direction because of occurrence of 3D crosstalk variation on screen. The 3D crosstalk variation on screen was occurred when the viewer's eye position moved back and forth along the Z‐axis direction. The reason was that the liquid crystal (LC) barrier pitch was fixed and the LC barrier was able to control the only barrier aperture position. To solve this problem, we developed the LC barrier that is able to control the barrier pitch as well as the barrier aperture position in real time, corresponding to the viewer's eye position. As a result, the 3D viewing space has achieved to expand up to 320–1016 mm from the display surface in the Z‐axis direction and within a range of ±267 mm in the X‐axis direction. In terms of the Y‐axis direction, the viewing space is not necessary to be considered, because of a stripe‐shaped parallax barrier.     

基于视差重映射的立体图像视觉舒适度提升

目的 针对人眼观看立体图像内容可能存在的视觉不舒适性,基于视差对立体图像视觉舒适度的影响,提出了一种结合全局线性和局部非线性视差重映射的立体图像视觉舒适度提升方法。方法 首先,考虑双目融合限制和视觉注意机制,分别结合空间频率和立体显著性因素提取立体图像的全局和局部视差统计特征,并利用支持向量回归构建客观的视觉舒适度预测模型作为控制视差重映射程度的约束;然后,通过构建的预测模型对输入的立体图像的视觉舒适性进行分析,就欠舒适的立体图像设计了一个两阶段的视差重映射策略,分别是视差范围的全局线性重映射和针对提取的潜在欠舒适区域内视差的局部非线性重映射;最后,根据重映射后的视差图绘制得到舒适度提升后的立体图像。结果 在IVY Lab立体图像舒适度测试库上的实验结果表明,相较于相关有代表性的视觉舒适度提升方法对于欠舒适立体图像的处理结果,所提出方法在保持整体场景立体感的同时,能更有效地提升立体图像的视觉舒适度。结论 所提出方法能够根据由不同的立体图像特征构建的视觉舒适度预测模型来自动实施全局线性和局部非线性视差重映射过程,达到既改善立体图像视觉舒适度、又尽量减少视差改变所导致的立体感削弱的目的,从而提升立体图像的整体3维体验。     

Interaction and visual performance in stereoscopic displays: A review

In this paper, authors systematically selected and reviewed articles related to stereoscopic displays and their advances, with a special focus on perception, interaction, and corresponding challenges. The aim was to understand interaction‐related problems, provide possible explanations, and identify factors that limit their applications. Despite promising advancements, there are still issues that researchers in the field fail to explain precisely. The two major problems in stereoscopic viewing are, compared with the real world, objects are perceived to be smaller than they actually are and there are discomfort and visual syndromes. Furthermore, there is general agreement that humans underestimate their egocentric distance in a virtual environment (VE). Our analysis revealed that in the real world, distance estimation is about 94% accurate, but in VE, it is only about 80% accurate. This problem could reduce the efficacy of different sensory motor‐based applications where interaction is important. Experts from human factors, computing, psychology, and others have studied contributing factors such as types of perception/response method, quality of graphics, associated stereoscopic conditions, experience in virtual reality (VR), and distance signals. This paper discusses the factors requiring further investigation if the VR interaction is to be seamlessly realized. In addition, engineering research directions aiming at improving current interaction performances are recommended.     

Experimental determination of the range of binocular disparity for which stereoscopic fusion occurs at a viewing distance of 2.5 m for a stereoscopic TV

The threshold for binocular disparity for which a participant can observe a clear stereoscopic image on a 3D TV using Patterned Retarder technology and polarizing eyeglasses is determined for a viewing distance of 2.5 m. An optotype, the letter “m” with a line thickness of 1.08 mm in the upward or downward direction, was used as the stereoscopic stimulus. Under the measurement conditions of the increase and decrease of binocular disparity of the stereoscopic stimulus, the binocular disparity thresholds for 40 participants were measured for the horizontal direction. Most of the participants were in their twenties. The thresholds were measured to be slightly larger for the condition of increasing binocular disparity compared with the condition of decreasing binocular disparity. Personal differences were measured to be noticeable.     

立体视频编码中运动和视差联合估计算法的研究

立体视频编码不仅要在同一个视点间进行运动估计,还要在相邻视点间进行视差估计,计算复杂度非常高.如何有效地结合运动估计和视差估计,降低运算复杂度是当前亟待解决的问题.本文详细分析了立体视频左右通道视频流之间的相关性,提出一种运动和视差联合估计快速算法.根据运动—视差模型,结合时空域的多参考帧来进行联合的运动和视差估计,实现对数据的有效编码压缩.实验证明,该算法与传统的全搜索算法相比,能在保证率失真性能基本不变的前提下,降低96.45%的运算复杂度,大大提高编码速度.     

Measurement of binocular disparity in polarized based stereoscopic display by using digital camera

This work presents an image displacement measurement by using a box pattern and the edge spread function analysis in the polarized based stereoscopic displays. The measurement determines to identify three factors (i.e., box size, image displacement, and spatial frequency response (SFR)) from the box patterns. The polarized based stereoscopic displays might sacrifice pixels for producing 3D images, which might produce errors in the image displacement and then affect the depth perception indirectly. Based on the measurement, the errors can be quantified by using the three factors. Owing to the light leakage distorting the edge spread function to obtain an inferior SFR, exactly how light leakage affects the edge spread function can be resolved on the basis of the SFR results, especially at a frequency (1/display pixel) of 1.9 in the case of the horizontal displacement. Light leakage also induces the error of the box height in even and odd intervals of the vertical displacements more than 2 pixels and 0.5 pixels, respectively. The image displacement measurement provides a simple and comprehensive means of evaluating the optical characteristics, disparity, and sharpness of the stereoscopic displays, via the three factors.     

模拟注视眼动的多聚焦彩色图像融合

多聚焦图像存在聚焦和离焦区。通常聚焦区吸引人的注意力,具有突出的视觉显著性。提出一种模拟人类视觉机制的彩色图像融合方法。利用超复数傅里叶变换改进传统显著性检测算法,直接检测彩色图像显著度;模拟人类视觉的注视眼动机制对图像尺度稍微扰动,并对不同尺度下获得的图像显著度进行累加;选择累计显著度最大的源图像像素构建融合图像,并采用颜色相似性准则处理边界带像素。相关仿真实验表明,超复数傅里叶变换充分利用了源图像的颜色信息,累加显著度能提高峰值信噪比并减少均方根误差。实验结果表明该方法可得到超过36 dB的峰值信噪比和小于个位数的均方误差,在图像融合中可得到相对好的主观视觉效果。     

Motivation determines Facebook viewing strategy: An eye movement analysis

Individuals' Social Networking Site (SNS) profiles are central to online impression formation. Distinct profile elements (e.g., Profile Picture) experimentally manipulated in isolation can alter perception of profile owners, but it is not known which elements are focused on and attributed most importance when profiles are viewed naturally. The current study recorded the eye movement behaviour of 70 participants who viewed experimenter-generated Facebook timelines of male and female targets carefully controlled for content. Participants were instructed to process the targets either as potential friends or as potential employees. Target timelines were delineated into Regions of Interest (RoIs) prior to data collection. We found pronounced effects of target gender, viewer motivation and interactions between these factors on processing. Global processing patterns differed based on whether a ‘social’ or a ‘professional’ viewing motivation was used. Both patterns were distinct to the ‘F’-shaped patterns observed in previous research. When viewing potential employees viewers focused on the text content of timelines and when viewing potential friends image content was more important. Viewing patterns provide insight into the characteristics and abilities of targets most valued by viewers with distinct motivations. These results can inform future research, and allow new perspectives on previous findings.     

人体自由运动状态下的视线追踪算法研究*

针对人体在大空间范围内自由运动时视线方向难以追踪的问题,构建了一套基于光学跟踪设备的头戴式视线追踪系统。系统通过被动式光学追踪设备和头戴式眼部摄像机获取使用者的头部运动状态与眼部图像,然后依据初始标定结果来估计使用者自由运动状态下的视线方向;最后对系统进行简化,得到了适用于同类环境、与具体硬件设备无关的视线跟踪三点三面三变换几何模型。对系统进行应用实验和误差分析表明,使用者在3.0 * 3.2 * 2.0 m的大工作空间内自由运动时视线追踪误差为1.69度,频率为20赫兹。     

族系间眼动行为模式多样性研究

中国是一个多民族国家,不同民族由于遗传、地域和文化等因素形成了不同的风俗和思考方式。为了研究不同民族观察事物时的眼动行为模式,利用Tobii眼动仪采集不同民族在求解数独问题时眼动轨迹表达数据,将不同族系被试的表达数据压缩为16维数据向量来构建数据集;分析对比布依族、蒙古族、朝鲜族、侗族和汉族等5个民族眼动行为数据集的多样性,利用多种机器学习方法对得到的数据进行测试分析。实验结果表明,族系间眼动行为存在多样性,同时为进一步深入探索不同族系间眼动行为的多样性提供了依据。     

Model-based approach to study of mechanisms of complex image viewing

A model-based approach to study complex image viewing mechanisms and the first results of its implementation are presented. The choice of the most informative regions (MIRs) is performed according to results of psychophysical tests with high-accuracy tracking of eye movements. For three test images, the MIRs were determined as image regions with maximal density of gaze fixations for the all subjects (n = 9). Individual image viewing scanpaths (n= 49) were classified into three basic types (i.e. “viewing”, “object-consequent”, and “object-returned” scanpaths). Task-related and temporal dynamics of eye movement parameters for the same subjects have been found. Artificial image scanpaths similar to experimental have been obtained by means of gaze attraction function. The article is published in the original.     

快速眼动信息识别算法研究

眼动信息能实时反映人类的心理变化及意识倾向, 虽然人眼比手更为灵敏, 但图像处理速度限制了帧速率的利用率, 不能有效捕捉眼动信息, 准确率也会大幅降低。针对目前现有的问题进行了图像匹配原理的研究, 设计了适合于眼动信息识别的单眼模板多层匹配算法, 并对该算法在常见干扰下进行实验和数据分析, 该检测算法运算速度快、准确度较高, 作为实时眼动信息识别算法有较高的应用价值。     

Assessment of visual fatigue caused by stereoscopic disparity based on multimodal measurement

Given the prevalence of visual fatigue induced by stereoscopic display, research on the neural mechanism of visual fatigue was limited. The goal of this study was to investigate the effect of stereoscopic display with different horizontal disparities on visual fatigue based on subjective questionnaire, ophthalmological parameters, eye movement and electrocardiogram (ECG). Subjects felt more headache, uncomfortable and dry eyes after watching 70-minute enhanced 3D display with larger negative disparity than normal 3D display. Meanwhile, visual function tear film break-up time (TBUT) reduced, microsaccade mean pupil diameter (MMPD) increased and heart rate variability (HRV) changed more significantly after watching enhanced 3D display. Overall, these results demonstrated that enhanced 3D display had a better sense of immersion, but it induced more visual fatigue significantly than normal 3D display.     

Using eye movement modelling examples to guide visual attention and foster cognitive performance: A meta-analysis

Eye movement modelling examples (EMME) are computer-based videos displaying the visualized eye gaze behaviour of a domain expert person (model) while carefully executing the learning or problem-solving task. The role of EMME in promoting cognitive performance (i.e., final scores of learning outcome or problem solving) has been questioned due to the mixed findings from empirical studies. This study tested the effects of EMME on attention guidance and cognitive performance by means of meta-analytic procedures. Data for both experimental and control groups and both posttest and pretest were extracted to calculate the effect sizes. The EMME group was treated as the experimental group and the non-EMME group was treated as the control group. Twenty-five independent articles were included. The overall analysis showed a significant effect of EMME on time to first fixation (d = −0.83), fixation duration (d = 0.74), as well as cognitive performance (d = 0.43), but not on fixation count, indicating that using EMME not only helped learners attend faster and longer to the task-relevant elements, but also fostered their final cognitive performance. Interestingly, task type significantly moderated the effect of EMME on cognitive performance. Moderation analyses showed that EMME was beneficial to learners' performance when non-procedural tasks (rather than procedural tasks) were used. These findings show contributions for future research as well as practical application in the field of computers and learning regarding videos displaying a model's visualized eye gaze behaviour.     

Effects of prior knowledge and joint attention on learning from eye movement modelling examples

Eye movement modelling examples (EMMEs) are instructional videos of a model's demonstration and explanation of a task that also show where the model is looking. EMMEs are expected to synchronize students' visual attention with the model's, leading to better learning than regular video modelling examples (MEs). However, synchronization is seldom directly tested. Moreover, recent research suggests that EMMEs might be more effective than ME for low prior knowledge learners. We therefore used a 2 × 2 between-subjects design to investigate if the effectiveness of EMMEs (EMMEs/ME) is moderated by prior knowledge (high/low, manipulated by pretraining), applying eye tracking to assess synchronization. Contrary to expectations, EMMEs did not lead to higher learning outcomes than ME, and no interaction with prior knowledge was found. Structural equation modelling shows the mechanism through which EMMEs affect learning: Seeing the model's eye movements helped learners to look faster at referenced information, which was associated with higher learning outcomes.     

基于前向搜索的快速视差范围估计方法

在立体匹配中,设置合理的视差搜索范围能够提高匹配的速度和精度。为此,提出了一种基于前向搜索的图像迭代细分方法用以估算视差范围的上下限。将参考图像均分为若干个图像块,在对每一块的匹配过程中,采用前向搜索策略,对当前匹配块继续均分成若干子块,并对其子块进行相似度匹配。在计算视差范围上限时,用当前块的子块视差中的最大值来表示其视差值,找到视差最大的图像块后继续迭代细分,直到得到稳定的视差范围上限。在计算视差范围下限时,用当前块的子块视差中的最小值来表示其视差值,找到视差最小的图像块后继续迭代细分,直到得到稳定的视差范围下限。实验结果表明,采用前向搜索策略计算视差范围的方法,在搜索空间降低比率达到28.8%的同时能够达到98%的命中率,相较直接进行匹配误匹配率降低了47.4%,能够得到更精确的视差范围。     

Effects of illumination conditions on preferred viewing distance of portable liquid‐crystal television

This study explored the effect of TV size, light source, and ambient illumination on the preferred viewing distance of portable liquid‐crystal‐display televisions. Results showed that the mean preferred viewing distance was 1389 mm. TV size had significant effects on preferred viewing distance. The larger the screen size, the greater the preferred viewing distance, at around 6.7–14.7 times the width of the screen (W). Light sources revealed no significant effect on preferred viewing distance. The effect of ambient illumination on preferred viewing distance was significant. The higher the ambient illumination was, the longer the preferred viewing distance.     

Selection of character/background colour combinations for onscreen searching tasks: An eye movement,subjective and performance approach

The aim of the study was to investigate the effect of various character and background colour combinations on cognitive performance during onscreen searching tasks and to identify the best combinations with a multimodal approach of physiological (eye movement recording), subjective and performance data collection. In the absence of proper character and background colour combination the optimum performance for a cognitive task is greatly affected which in turn affects the productivity of the individual worker or communications among the operators working under the same network through information sharing. This study was designed by selecting six colours, i.e., white, black, yellow, red, blue, and green and subsequently combining them to 16 character and background colour combinations for a searching task. Right and left headed arrows were used as the character for the searching maneuver. Forty-four (N = 44) volunteers participated in the experiments. Various eye movement variables, legibility rating scale, NASA-TLX questionnaire, searching time and percentage of error were recorded. Subjects performed better wherever a good contrast was there because of a high legibility. A poorly contrasted display affected the physiological variables as well as subjective responses to negative directions. Among the combinations of dark character/light background, blue and red character on white background is highly recommended; and while that for light character/dark background, white is found to be the best character on blue and green backgrounds.     

基于用户自定义兴趣区的飞行员眼动数据可视分析方法

针对传统基于兴趣区的可视化方法在分析飞行员眼动数据过程中无法关注细节的问题,提出了一种基于用户自定义兴趣区的眼动数据可视分析方法。首先,根据具体的分析任务,引入对任务背景图像的自我划分和定义;然后,在此基础上,结合多种辅助视图和交互手段,设计并实现了面向飞行员培训的眼动数据可视分析系统,帮助分析人员分析不同的飞行员之间的眼动差异,最后通过案例分析,证明了可视分析方法的有效性和分析系统的实用性。实验结果表明,较传统方法来说,所提方法增加了分析人员在分析过程中的主动性,在整体和局部方面,支持分析人员对任务背景进行细节的探索,增加了分析人员分析数据的多角度性,让分析人员能够结合整体发现飞行学员在训练过程中认知困难的部分,进而制定更有针对性、更有效的训练课程。     

基于眼动分析的文化设计基因提取与应用研究

将文化与生物学领域的基因概念相结合,提出了基于眼动分析的文化设计基因的提取方法。以彬县大佛寺石窟为案例,运用眼动分析方法将人对文化特征的感性认识量化分析,确定出提取文化设计基因的重点,从图案、形态、色彩、材质四方面分别提取文化设计基因,通过演绎、重组改善设计基因的表达,并应用于产品文化创意设计,为文化遗产的特征提取和创新应用提供参考。