Three views of virtual reality: an overview

Virtual reality (VR) presents a synthetically generated environment to the user through visual, auditory, and other stimuli. A VR systems's head-mounted display, stereo graphics, and direct manipulation in three dimensions are outlined. Early work in VR and major technological hurdles in the areas of tracking, display, image generation, and software support are reviewed. Research directions and potential applications of VR are discussed     

Computer-based tests: the impact of test design and problem of equivalency

Nowadays, computerized forms of psychodiagnostic methods are often produced without providing appropriate psychometric characteristics, or without proving equivalency with conventional forms. Moreover, there exist tests with more than one computerized versions, which are mostly designed differently. Study I focused on the impact of test design. It was found that even simple change of color scheme (light stimuli on dark background vs. dark stimuli on light background) had a significant effect on subjects’ performance. Study II examined equivalency of a computerized speeded test, which is broadly used within psychological practitioners in the Czech Republic; this form was found non-equivalent with its conventional counterpart.     

Computer anxiety and measurement of mood change

Approximately 30% of the UK population have been characterised as suffering, to some extent, from computer anxiety, showing either physiological, cognitive, or negatively affective reactions when working with computers. In this study, the relationship between computer anxiety and self-ratings of mood change was investigated. Mood was measured either by a computerized form of visual analog scales or by an identical test administered by paper-and-pencil. Positive mood change was manipulated by a modified Velten-type Mood Induction Procedure (VMIP, Velten, 1968) administered via a computer. Undergraduate student volunteers (40 males and 68 females) completed visual analog mood scales before and after the VMIP. The correlation between self-ratings of mood and the computer anxiety scores was significantly greater in the computer compared with the paper-and-pencil groups. Computer anxiety related to measured mood when the mood measurements were collected using the computerized procedure but not the paper procedure. The implications of these findings for the clinical application of computerized mood assessment are discussed.     

fMRI的视觉神经信息编解码方法综述

视觉神经信息编解码旨在利用功能磁共振成像(functional magnetic resonance imaging,fMRI)等神经影像数据研究视觉刺激与大脑神经活动之间的关系。编码研究可以对神经活动模式进行建模和预测,有助于脑科学与类脑智能的发展;解码研究可以对人的视知觉状态进行解译,能够促进脑机接口领域的发展。因此,基于fMRI的视觉神经信息编解码方法研究具有重要的科学意义和工程价值。本文在总结基于fMRI的视觉神经信息编解码关键技术与研究进展的基础上,分析现有视觉神经信息编解码方法的局限。在视觉神经信息编码方面,详细介绍了基于群体感受野估计方法的发展过程;在视觉神经信息解码方面,首先,按照任务类型将其划分为语义分类、图像辨识和图像重建3个部分,并深入阐述了每个部分的代表性研究工作和所用的方法。特别地,在图像重建部分着重介绍了基于深度生成模型(主要包括变分自编码器和生成对抗网络)的简单图像、人脸图像和复杂自然图像的重建技术。其次,统计整理了该领域常用的10个开源数据集,并对数据集的样本规模、被试个数、刺激类型、研究用途及下载地址进行了详细归纳。最后,详细介绍了视觉神经信息编解码模...     

Visual product evaluation: exploring users' emotional relationships with products

This paper discusses an industrial designer's approach to eliciting user perceptions and emotional responses to products through visual evaluation and stimuli. Whilst the authors accept that product functionality is crucial for product success, the appearance, use of materials, shape and form provide the most immediate product data for the user. Less tangible issues such as emotional bonding of users with products, cultural perceptions and social value systems, provide valuable insights for the product developer to help expand knowledge and understanding of the users' need beyond the functional. This paper presents product personality profiling as a new technique for design researchers/designers, and discusses it alongside other emerging approaches such as mood boards and visual product evaluation. The authors have used these techniques during focus group sessions with users to elicit individuals' needs and aspirations towards products. Such a user-centred approach is fundamental to applied ergonomics. Experiences, benefits, and limitations of these techniques are outlined as well as the opportunities for further development.     

Development and evaluation of BCI for operating VR flight simulator based on desktop VR equipment

Advancement of brain-computer interface (BCI) has shown its applications in various scenarios, including flight control. Flight simulator is a crucial part for aircraft design or experiment. Desktop virtual reality (VR)-based flight is a perfect choice for overcoming existing problems in head-mounted VR flight simulations, such as dizziness and isolation, which make interaction and sharing very difficult. In this paper, a BCI based on the steady-state visual evoked potential paradigm and a VR flight simulator were developed and integrated. The performance of the developed system was evaluated quantitatively for comparative studies. Experimental results show that the developed system is very convenient and suitable for VR flight simulations. The average operating accuracies with plane and VR visual stimuli are 81.6% and 86.8%, respectively. The VR visual stimuli can improve the average operating accuracy by 5.2% compared with the plane visual stimuli.     

A computer monitored chemical reaction

The instrumental set-up as well as the program structure is presented for a solution phase chemical reaction in process control. Educational applications are outlined for its use within a physical chemistry laboratory course. By means of this experiment students are introduced and acquainted with computerized instrumentations, data acquisition, data reduction, and process control.     

Effect of visual field asymmetries on performance while utilizing aircraft attitude symbology

This research explores the effect of symbology placement on human performance for users of head-mounted augmented reality displays. A pair of experiments examined the impact on visual performance asymmetries when perceiving complex, meaningful visual stimuli, such as the Arc Segment Attitude Reference (ASAR). The ASAR symbology represents an aircraft’s vertical flight path and roll angles. Experiment 1 examined participants’ performance in making categorical and coordinate judgments regarding various attitudes of the ASAR and a Gabor patch which were briefly presented in the peripheral visual field. The results were consistent with the horizontal-vertical anisotropy literature, which implies that performance would be better for stimuli placed on the horizontal than the vertical meridian. Experiment 2 assessed asymmetries for continuously presented stimuli in a dual-task environment which involved a centrally located, demanding visual psychomotor task and monitoring of the ASAR or Gabor stimuli at the same peripheral locations as Experiment 1. No performance differences were found as a function of peripheral stimulus placement. However, eye tracking, particularly for a subset of the participants suggest they employed a more efficient visual process to monitor the peripheral stimuli when the stimuli were placed on the horizontal meridian.     

基于W77 E58的电脑绣花机控制系统

给出了基于W77 E58的电脑绣花机控制系统设计方案及控制系统软件实现,此系统功能强大、开发周期短、开发费用低。     

The visual hull of smooth curved objects

The visual hull is a geometric entity that relates the shape of an object to its silhouettes or shadows. This paper develops the theory of the visual hull of generic smooth objects. We show that the visual hull can be constructed using surfaces which partition the viewpoint space of the aspect graph of the object. The surfaces are those generated by the visual events tangent crossing and triple point. An analysis based on the shape of the object at the tangency points of these surfaces allows pruning away many surfaces and patches not relevant to the construction. An algorithm for computing the visual hull is outlined.     

The impact of distractions on the usability and intention to use mobile devices for wireless data services

Mobile technology has quickly become ingrained in society due to the flexibility of anywhere/anytime usage. However, factors associated with and that impact mobility, mobile users, and mobile use of products and services are still poorly understood. For example, even though distractions are ever present during everyday use of mobile devices, the nature and extent to which user perceptions and performance are affected by their presence is unknown. An empirical study was undertaken to investigate the impact of distractions and confirmation of pre-trial expectations on usability and its subsequent effect on consumers’ behavioral intention toward using a mobile device for wireless data services. Distractions were simulated in this study in the form of either user motion or environmental noise (i.e. background auditory and visual stimuli). A Structural Equation Modelling (SEM) analysis confirmed the impacts of distractions on efficiency and effectiveness, and in turn the users’ satisfaction and behavioral intention to use a mobile device for wireless data services. Support was also obtained for a mediating effect of post-trial confirmation of expectations between perceived performance and satisfaction. Implications of these findings for theory, practice, and future research are outlined.     

Eye monitor: microcomputer-based instrument uses an internal modeto track the eye

An eye monitor whose design is inspired by the human visual system is presented. The monitor incorporates an internal representation or model of what the eye looks like to a video camera. The system can measure the position of the eyes and the size of the pupil in the presence of interfering noise and in patients wearing eyeglasses or contact lenses, and it tolerates defocusing due to small movements in depth by the patient. The system makes real-time correction for head and eye movements while measuring pupillary responses to controlled light stimuli. The design and software and hardware components are described, and some applications are noted. Its use for early clinical detection of visual diseases by objectively measuring pupillary responses to carefully controlled light stimuli is examined as an example. Some general observations about using computers in medical measurements are made     

Adaptive integration in the visual cortex by depressing recurrent cortical circuits

Neurons in the visual cortex receive a large amount of input from recurrent connections, yet the functional role of these connections remains unclear. Here we explore networks with strong recurrence in a computational model and show that short-term depression of the synapses in the recurrent loops implements an adaptive filter. This allows the visual system to respond reliably to deteriorated stimuli yet quickly to high-quality stimuli. For low-contrast stimuli, the model predicts long response latencies, whereas latencies are short for high-contrast stimuli. This is consistent with physiological data showing that in higher visual areas, latencies can increase more than 100 ms at low contrast compared to high contrast. Moreover, when presented with briefly flashed stimuli, the model predicts stereotypical responses that outlast the stimulus, again consistent with physiological findings. The adaptive properties of the model suggest that the abundant recurrent connections found in visual cortex serve to adapt the network's time constant in accordance with the stimulus and normalizes neuronal signals such that processing is as fast as possible while maintaining reliability.     

Affective saliency map considering psychological distance

This paper proposes a new affective saliency map (SM) model considering psychological distance as well as the pop-out property based on relative spatial distribution of the primitive visual features such as intensity, edge, color, and orientation. By reflecting congruency between the spatial distance caused by spatial proximity and distal in a visual scene and psychological distance caused by the way people think about visual stimuli, the proposed SM model can produce more human-like visual selective attention than a conventional SM model based on primary visual perception. In the proposed model, a psychological distance caused by a social distance, in which a proximal entity such as friend becomes more attractive when it is located near but a distal entity such as enemy becomes more attractive when it is located far from an observer, is considered. In the experiments, two types of visual stimuli are considered, mono-stimuli and stereo-stimuli. In the case of mono-stimuli, the visual stimuli on a picture with psychological depth cues were considered. Instead, in the case of stereo-stimuli, depth perception is also considered for obtaining real spatial distance of visual target in a visual scene. In order to verify the proposed affective SM model, an eye tracking system was used to measure the visual scan path and fixation time on a specific local area while monitoring the visual scenes by human subjects. Experimental results show that the proposed model can generate plausible visual selective attention properly reflecting both psychological distance and primitive visual stimuli inducing pop-out bottom-up features.     

Edge detection and motion detection

This paper presents an integrated theory of edge detection, curvature measurement and motion detection during the earliest stages of visual processing. No assumptions are necessary about the viewed objects or about surface properties and the viewing geometry. New methods are outlined for edge detection, curvature measurement and correspondence matching by successive refinement.     

Perceptual training for visual search

People are better at visual search than the best fully automated methods. Despite this, visual search remains a difficult perceptual task. The goal of this investigation was to experimentally test the ways in which visual search performance could be improved through two categories of training interventions: perceptual training and conceptual training. To determine the effects of each training on a later performance task, the two types of trainings were manipulated using a between-subjects design (conceptual vs. perceptual × training present vs. training absent). Perceptual training led to speed and accuracy improvements in visual search. Issues with the design and administration of the conceptual training limited conclusions on its effectiveness but provided useful lessons for conceptual training design. The results suggest that when the visual search task involves detecting heterogeneous or otherwise unpredictable stimuli, perceptual training can improve visual search performance. Similarly, careful consideration of the performance task and training design is required to evaluate the effectiveness of conceptual training.

Practitioner Summary: Visual search is a difficult, yet critical, task in industries such as baggage screening and radiology. This study investigated the effectiveness of perceptual training for visual search. The results suggest that when visual search involves detecting heterogeneous or otherwise unpredictable stimuli, perceptual training may improve the speed and accuracy of visual search.     

Graphics for environmental decision making

Applications, problems, research needs, and future requirements of visual decision support systems, the systems relied on for environmental care and planning, are discussed. Environmental decision software, visual techniques, data types, and geometries are outlined. The examples of environmental applications for visual decision support systems-pollution monitoring and water risk assessment-are presented     

How much information is associated with a particular stimulus?

Although the Shannon mutual information can be used to reveal general features of the neural code, it cannot directly address which symbols of the code are significant. Further insight can be gained by using information measures that are specific to particular stimuli or responses. The specific information is a previously proposed measure of the amount of information associated with a particular response; however, as I show, it does not properly characterize the amount of information associated with particular stimuli. Instead, I propose a new measure: the stimulus-specific information (SSI), defined to be the average specific information of responses given the presence of a particular stimulus. Like other information theoretic measures, the SSI does not rely on assumptions about the neural code, and is robust to non-linearities of the system. To demonstrate its applicability, the SSI is applied to data from simulated visual neurons, and identifies stimuli consistent with the neuron's linear kernel. While the SSI reveals the essential linearity of the visual neurons, it also successfully identifies the well-encoded stimuli in a modified example where linear analysis techniques fail. Thus, I demonstrate that the SSI is an appropriate measure of the information associated with particular stimuli, and provides a new unbiased method of analysing the significant stimuli of a neural code.     

Neuronal processing of behaviourally generated optic flow: experiments and model simulations

The stimuli traditionally used for analysing visual information processing are much simpler than what an animal sees when moving in its natural environment. Therefore, we analysed in a previous study the performance of an identified neuron in the optomotor system of the fly by using as visual stimuli image sequences that were experienced by the animal while walking in a structured environment. These electrophysiological experiments revealed that the fly visual system computes from behaviourally generated optic flow a rather unambiguous representation of the animal's self-motion. In contrast to conclusions based on simple stimuli, the directions of turns are represented by an interneuron, the HSE cell, quite independent of the spatial layout of the environment and its textural properties when the cell is stimulated with behaviourally generated optic flow. This conclusion is substantiated here by further experimental evidence. Moreover, it is shown that the largely unambiguous responses of the HSE cell to behaviourally generated optic flow can be replicated to a large extent by a network model of the fly's visual motion pathway. These results stress the significance of naturalistic stimuli for analysing what is encoded by neuronal circuits under natural operating conditions.     

A model for experience-dependent changes in the responses of inferotemporal neurons

Neurons in inferior temporal (IT) cortex exhibit selectivity for complex visual stimuli and can maintain activity during the delay following the presentation of a stimulus in delayed match to sample tasks. Experimental work in awake monkeys has shown that the responses of IT neurons decline during presentation of stimuli which have been seen recently (within the past few seconds). In addition, experiments have found that the responses of IT neurons to visual stimuli also decline as the stimuli become familiar, independent of recency. Here a biologically based neural network simulation is used to model these effects primarily through two processes. The recency effects are caused by adaptation due to a calcium-dependent potassium current, and the familiarity effects are caused by competitive self-organization of modifiable feedforward synapses terminating on IT cortex neurons.