Latency of peripheral saccades

Displaying the point of gaze to the observer in addition to a point target provides a secondary visual feedback (2VFB). Eccentric fixation is achieved using a biased 2VFB to yield an experimentally imposed "eccentric fovea." The target is suddenly moved to a new position and the task is to regain it, in the "eccentric fovea". It is found that the pattern of eye-movement response consistently starts with saccadric foveal exploration of the target, but its latency has twice the duration of a regular voluntary saccade. Practice, however, makes for the shortened latency tending asymptotically to the regular saccadic duration.     

An Adaptive Algorithm for Eye-Gaze-Tracking-Device Calibration

Eye-gaze tracking has been an important and interesting area of research for quite some time now. In laboratory experiments for psychological research, eye-gaze tracking constitutes a helpful tool to probe the perceptual or the cognitive processes of the subjects. In day-to-day applications, eye-gaze tracking can be used as a computer interface for both industrial and nonindustrial applications, which require hands-free installations. It can also be used to help disabled people to use computers for communication and for environmental control. This paper aims to develop a computer system to facilitate the study of visual scanning and eye fixation during image exploration. The system uses an infrared device to detect horizontal and vertical eye movements. This paper mainly focuses its attention on the calibration procedure that can be effectively utilized for correction of the nonlinearities in the oculomotor for the eyes of each individual subject. An adaptive calibration algorithm has been developed by employing a polynomial model. Several experiments have been carried out to demonstrate that the proposed approach is a rapid one and is accurate for the study of visual perception and recognition processes.     

Effects of negative afterimages in visual illusions

We show that a broad class of visual illusions, including illusory motion, can be explained by the effects of negative afterimages. Two new illusions, illusory shading and illusory tilting, are devised on the basis of the proposed explanation. The general feature of these illusions is an alternation between a high-contrast (white or black) and a low-contrast (gray) local input signal, which can be caused either by eye motion over patterns of varied luminance or by a change in such patterns over time. A simple model of the local signal dynamics qualitatively reproduces the illusory effects by adding the negative afterimage to the original visual stimulus.     

老龄服务机器人色彩设计的视觉认知绩效研究

目的 在智能养老广泛应用的背景下,探索服务机器人设计色彩对老年人视觉认知绩效的影响。方法 选取24名老年被试者进行眼动实验,获取被试者观察8组实验图片时的眼动指标。首先,对总注视次数和第一次注视时间这两项眼动数据进行客观分析,采用单因素方差分析方法来验证数据的显著性;其次,对老年被试者与青年被试者数据进行t检验分析,研究不同年龄段用户对服务机器人色彩设计的视觉认知绩效是否存在差异;最后,利用相关性分析方法验证色弱是否会影响老年人的视觉认知绩效。结论 老年人对黑色比较敏感,对白色极容易忽略,冷暖色之间不存在显著差异;不同年龄段用户对颜色关注度存在差异;色弱会略微影响老年人的视觉认知绩效,但不会影响老年人对色彩的选择。     

Automated detection of foveal fixation by use of retinal birefringence scanning

Foveal fixation was monitored in normal subjects remotely and continuously by use of a noninvasive retinal scan. Polarized infrared light was imaged onto the retina and scanned in a 3 degrees annulus at 44 Hz. Reflections were analyzed by differential polarization detection. In all 32 eyes studied, the detected signal was predominantly 88 Hz during central fixation (within +/-1 degree) and 44 Hz during paracentral fixation. Phase shift at 44 Hz correlated with the direction of eye displacement. Potential applications of this technique include screening for eye disease, eye position monitoring during clinical procedures, and use of eye fixation to operate devices.     

食品包装材质对消费者绿色购买意愿影响的眼动研究

目的 探讨食品包装材质对消费者注意加工流程和绿色购买意愿影响的内在机制。方法 采用包装材质2(环保/普通)×食品类型2(实用品/享乐品)双因素实验设计,在货架购物场景下采用Tobii Glasses 2眼镜式眼动仪,采集被试者浏览货架不同食品时的眼动数据(平均注视时间、注视次数、热点图),并结合行为数据综合分析。结果 在平均注视时间上,包装材质与食品类型的交互作用显著,注视次数交互作用不显著;环保材质包装的食品获得更多关注,被试者偏好于选择环保包装的享乐食品。结论 包装材质与食品类型共同影响消费者的视觉感知效果与加工过程,环保包装对青年消费者的绿色购买意愿有正向促进作用。     

Adaptive optics binocular visual simulator to study stereopsis in the presence of aberrations

A binocular adaptive optics visual simulator has been devised for the study of stereopsis and of binocular vision in general. The apparatus is capable of manipulating the aberrations of each eye separately while subjects perform visual tests. The correcting device is a liquid-crystal-on-silicon spatial light modulator permitting the control of aberrations in the two eyes of the observer simultaneously in open loop. The apparatus can be operated as an electro-optical binocular phoropter with two micro-displays projecting different scenes to each eye. Stereo-acuity tests (three-needle test and random-dot stereograms) have been programmed for exploring the performance of the instrument. As an example, stereo-acuity has been measured in two subjects in the presence of defocus and/or trefoil, showing a complex relationship between the eye's optical quality and stereopsis. This instrument might serve for a better understanding of the relationship of binocular vision and stereopsis performance and the eye's aberrations.     

Measuring miniature eye movements by means of a SQUID magnetometer

A new technique to measure small eye movements is reported. The precise recording of human eye movements is necessary for research on visual fatigue induced by visual display units.¹ So far all methods used have disadvantages: especially those which are sensitive or are rather painful.^2,3 Our method is based on a transformation of mechanical vibrations into magnetic flux variations. In order to do this a small magnet is embedded in a close-fitting soft contact lens. The magnetic flux variations caused by eyeball movements during fixation are measured by means of a SQUID magnetometer. The recordings show the typical fixation pattern of a human eye. This pattern is composed of three kinds of movements: saccades, drift and microtremor. The last-mentioned type of movements are displacements in the order of 2 μm. It is possible to distinguish between movements which are perpendicular to each other.     

Automated detection of ocular alignment with binocular retinal birefringence scanning

We previously developed a retinal birefingence scanning (RBS) device to detect eye fixation. The purpose of this study was to determine whether a new binocular RBS (BRBS) instrument can detect simultaneous fixation of both eyes. Control (nonmyopic and myopic) and strabismic subjects were studied by use of BRBS at a fixation distance of 45 cm. Binocularity (the percentage of measurements with bilateral fixation) was determined from the BRBS output. All nonstrabismic subjects with good quality signals had binocularity >75%. Binocularity averaged 5% in four subjects with strabismus (range of 0-20%). BRBS may potentially be used to screen individuals for abnormal eye alignment.     

呈现方式和任务导向对网络广告受众的眼动影响

考察呈现方式和任务导向对网络广告受众注意的影响。研究采用2(呈现方式:动态切换、静态)×2(任务导向:目标、非目标)的被试间设计。结果发现:(1)被试对动态广告和静态广告的注视次数及注视时间均无显著差异;(2)非目标导向的被试对网络广告的注视次数及注视时间均显著多于目标导向的被试;(3)相比于认知评价法,眼动分析法对网络广告效果的评估更为精细准确。研究表明,网络广告受众注意受任务导向的影响,而不受呈现方式的影响。     

游艇关键造型特征的眼动追踪研究

目的 为建立眼动数据和感性意象评价之间的数学关系,提出一种基于眼动参数的造型评价方法。方法 以游艇为研究对象,通过SMIRED500型眼动仪设备的应用,结合语义差分法进行主观评价,通过眼动追踪记录受试者在观看不同造型风格游艇时的眼动数据,对采集的眼动数据进行单因素方差分析,保留瞳孔直径大小、总注视时间、眼跳到该区域次数及首视点持续时间四项有效眼动数据,并结合主观问卷探讨不同游艇的视觉认知规律,采用多元线性回归方程进行数据建模,明确各项眼动数据对感性评价的影响权重,研究了被视者的眼动追踪数据与主观评价之间的关联关系。结论 建立眼动数据与感性评价之间的数学关系模型,并验证了模型的有效性,对产品造型方案评选及产品设计方案改进提供了有力的支持。     

夜间照明环境对电纸书阅读工效的影响

目的 探究夜间照明环境对电纸书阅读工效及视疲劳的影响,探索更有益于用户生理与心理的照明方式及相对应的照明参数。方法 采用内外置照明方式对比实验,以视觉搜索绩效和瞳孔直径变异系数分别作为阅读工效与视疲劳症状的评价指标,结合主观生理评价指标作为对照。结论 在两种照明方式下,照度为350 lux时阅读绩效最高,且视疲劳程度更大。从主观生理感受评价可知,内置照明方式下采用最低照度150 lux时被试感到麻木,使用外置照明方式被试整体感受较好,头晕与眼部疲劳症状不明显。综合可得,外置照明方式在阅读工效以及视疲劳症状上优于内置照明方式。     

Monochromatic aberrations of human eyes in the horizontal visual field

We measured the monochromatic aberrations of five subjects' right eyes both temporally and nasally out to 40 degrees from fixation. We used a Hartmann-Shack sensor with modifications to equipment and software to enable off-axis measurements. Results were standardized for 6-mm pupils. There was considerable variation among subjects in the pattern of aberrations. Aberrations were generally greater in the nasal visual field than in the temporal visual field; in the case of third-order aberrations, this was true for all subjects. The contribution of third-order Zernike aberrations to the root-mean-square aberration increased up to four times from the center to the edge of the field, but the contribution of fourth- to sixth-order Zernike aberrations varied little across the visual field. Results were similar to those of a previous investigation using laser ray tracing and were of the order of those predicted by Navarro's finite schematic eye.     

Contrast statistics for foveated visual systems: fixation selection by minimizing contrast entropy

The human visual system combines a wide field of view with a high-resolution fovea and uses eye, head, and body movements to direct the fovea to potentially relevant locations in the visual scene. This strategy is sensible for a visual system with limited neural resources. However, for this strategy to be effective, the visual system needs sophisticated central mechanisms that efficiently exploit the varying spatial resolution of the retina. To gain insight into some of the design requirements of these central mechanisms, we have analyzed the effects of variable spatial resolution on local contrast in 300 calibrated natural images. Specifically, for each retinal eccentricity (which produces a certain effective level of blur), and for each value of local contrast observed at that eccentricity, we measured the probability distribution of the local contrast in the unblurred image. These conditional probability distributions can be regarded as posterior probability distributions for the "true" unblurred contrast, given an observed contrast at a given eccentricity. We find that these conditional probability distributions are adequately described by a few simple formulas. To explore how these statistics might be exploited by central perceptual mechanisms, we consider the task of selecting successive fixation points, where the goal on each fixation is to maximize total contrast information gained about the image (i.e., minimize total contrast uncertainty). We derive an entropy minimization algorithm and find that it performs optimally at reducing total contrast uncertainty and that it also works well at reducing the mean squared error between the original image and the image reconstructed from the multiple fixations. Our results show that measurements of local contrast alone could efficiently drive the scan paths of the eye when the goal is to gain as much information about the spatial structure of a scene as possible.     

Heterochromatic Brightness Match Variability and Transient Adaptation

The discrepancy between the relative brightness and the relative luminance of two lights, one much more highly saturated than the other, is found to decrease markedly over a period of 2-3 min of steady fixation. This finding suggests temporal differences in the adaptive characteristics of chromatic and achromatic visual channels. When the eye has become adapted to the test field, the brightness-luminance discrepancy can be revived to some extent by introducing modest perturbations in the luminance of the relatively unsaturated light. Failure to control the temporal variable could be a major source of the differences, both from subject to subject and within the same subject, often found in heterochromatic brightness matching.     

The Effect of Modifying Structure to Display Product Versus Graphical Representation on Packaging

Research is presented that investigates whether the amount of physical product visible from the primary display panel of a package has an effect on consumer attention and purchase decision in the category of grill ware. It is hypothesized that a package providing the most physical product exposure will be preferred by consumers over alternative structural designs. To test this, three similar products were placed in four distinct package structures varying the amount of visible product exposure (0%, 40%, 90% and 100%). The packages were positioned on the shelves of the fully immersive simulated shopping environment CUshop?. A total of 127 participants were fitted with eye‐tracking glasses and presented a shopping list that included one of the three grill ware products (fork, spatula and tongs). Participants were asked to shop as they normally would, and data concerning their visual attention in the store and final purchase selection was collected. Purchase patterns showed that the packaging that revealed the most physical product possible was chosen more than the other three configurations tested. Analysis of eye‐tracking data supports expected behaviour, suggesting that consumers prefer to see at least some of the product, with the 0% visible product receiving significantly fewer fixations, a slower time to first fixation and lower total fixation durations. Copyright © 2012 John Wiley & Sons, Ltd.     

Dynamical use of different sources of information in heading judgments from retinal flow.

The optic flow arising in the eyes of an observer during self-motion is influenced by the occurrence of eye movements. The determination of heading during eye movements may be based on the pattern of retinal image motion (the retinal flow) or on an additional use of an extraretinal eye-movement signal. Previous research has presented support for either of these hypotheses, depending on the movement geometry and the layout of the visual scene. A special situation in which all previous studies unequivocally have agreed that an extra-retinal signal is required occurs when the visual scene consists of a single frontoparallel plane. In this situation eye movements shift the center of expansion on the retina to a location that does not correspond to the direction of self-movement. Without extraretinal input, human observers confuse the center of expansion with their heading and show a systematical heading estimation error. We reexamined and further investigated this situation. We presented retinal flow stimuli on a large projection screen in the absence of extra-retinal input and varied stimulus size, presentation duration, and orientation of the plane. In contrast to previous studies we found that in the case of a perpendicular approach toward the plane, heading judgments can be accurate. Accurate judgments were observed when the field of view was large (90 degrees x 90 degrees) and the stimulus duration was short (< or = 0.5 s). For a small field of view or a prolonged stimulus presentation, a systematic and previously described error appeared that is related to the radial structure of the flow field and the location of the center of expansion. An oblique approach toward the plane results in an ambiguous flow field with two mathematically possible solutions for heading. In this situation, when the stimulus duration was short, subjects reported a perceived heading midway between these two solutions. For longer flow sequences, subjects again chose the center of expansion. Our results suggest a dynamical change in the analysis or interpretation of retinal flow during heading perception.     

目标出现概率、目标有无和时间压力对视觉搜索绩效的影响

生产生活中很多视觉搜索任务是在低目标出现概率、有时间压力的条件下进行的。本研究分析了目标出现概率、目标有无和时间压力对视觉搜索任务绩效的影响。实验将目标出现概率作为组间变量,目标有无和时间压力作为组内变量,进行了完全2×2×2因子实验设计。结果表明时间压力和低目标出现概率会显著降低搜索时间、凝视时间和凝视次数。目标有无和时间压力、目标有无和目标出现概率对搜索时间的影响交互效应显著。时间压力和目标出现概率对搜索时间的影响交互效应不显著,但对凝视时间和凝视次数的影响交互效应显著。实验结果对于视觉搜索作业任务设计,尤其是如安检等有时间压力、低目标出现概率的作业任务设计具有指导意义。      

经验因素与车道类型对汽车驾驶员变道决策的影响

目的考察驾驶经验与车道类型对驾驶员变道决策的影响以及不同经验驾驶员的眼动注意搜索模式。方法使用Tobii眼动仪和驾驶场景视频收集了35名驾驶员的变道决策反应时、变道频率及眼动数据。结果驾驶经验与车道类型对驾驶员变道决策反应时交互作用显著;驾驶经验、车道类型与兴趣区对驾驶员总注视时间交互作用显著,同时驾驶员前方视野总注视时间对其边侧车道变道决策反应时有负向预测作用。结论中间车道条件下,实习驾驶员变道决策反应时更慢;边侧车道条件下结论相反;中间车道条件下,实习驾驶员对于侧视镜的总注视时间更长;边侧车道条件下,实习驾驶员对于前方视野的总注视时间更长;边侧车道条件下,实习驾驶员对于前方视野注视时间越长,变道决策反应时越快,这可以被视为实习驾驶员变道决策反应时更快的主要视觉注意机制。本研究对驾驶员改善变道行为和安全驾驶具有重要意义。     

A biologically inspired modular VLSI system for visual measurement of self-motion

We introduce a biologically inspired computational architecture for small-field detection and wide-field spatial integration of visual motion based on the general organizing principles of visual motion processing common to organisms from insects to primates. This highly parallel architecture begins with two-dimensional (2-D) image transduction and signal conditioning, performs small-field motion detection with a number of parallel motion arrays, and then spatially integrates the small-field motion units to synthesize units sensitive to complex wide-field patterns of visual motion. We present a theoretical analysis demonstrating the architecture's potential in discrimination of wide-field motion patterns such as those which might be generated by self-motion. A custom VLSI hardware implementation of this architecture is also described, incorporating both analog and digital circuitry. The individual custom VLSI elements are analyzed and characterized, and system-level test results demonstrate the ability of the system to selectively respond to certain motion patterns, such as those that might be encountered in self-motion, at the exclusion of others.