The effects of visual lobe training with easy and difficult targets on changes of visual lobe shape characteristics and visual search performance

This study aimed to study the effects of training on visual lobe shape characteristics with two levels of target difficulty (an easy target O and a difficult target V) and to study the transfer effect from lobe shape training to visual search performance. It was found that there was a noticeable improvement in lobe area and roundness for the difficult target lobes with the difficult target training groups, and that lobe area and roundness showed greatest sensitivity to the effects of training. The easy target lobes for the difficult target training group did not show any differences between pretest and posttest. There was a narrowing of differences in shape parameters between the two target difficulties from pretest to posttest after lobe mapping practice, suggesting that such practice could minimize lobe shape differences for different job difficulties. Search task practice was found to improve search performance, but lobe training produced no additional benefit for search time. Correlation analysis between lobe shape parameters and search time showed that a significant relationship existed only for the long time search task, indicating that mathematical models previously developed for search performance prediction may not be valid for short time search tasks.

Relevance to industry

This research showed the relative sensitivity of different lobe shape indexes from training and indicated the importance of selecting an appropriate level of target difficulty for enhancing training effectiveness.     

Visual lobe shape and search performance for targets of different difficulty

In quantitative models of visual search it has usually been assumed that visual lobe area shape was sufficiently regular to be approximated by a circle or ellipse. However, the irregularities in visual lobe shapes that have been found in studies involving extensive lobe mapping have suggested that lobe shape may have important implications for visual search performance and for the accuracy of mathematical models used for performance prediction. However, no systematic research on the relationship between the shape aspect of visual lobes and search performance seems to have been carried out and no comparisons of visual lobe shape characteristics under the effect of target difficulty have been reported. The current study was conducted to achieve two major objectives in two experiments. Experiment 1 used two different targets (letter ‘O’ and letter ‘Y’) to map the visual lobes of subjects in order to provide a systematic and quantitative comparison of lobe shape characteristics and experiment 2 was to investigate the correlation of visual lobe shape characteristics with visual search time under the effect of target difficulty. The visual lobes of 28 subjects were mapped on 24 imaginary and regularly spaced meridians originating from the centre of the visual field to resemble the full field mapping situation. Five categories of shape indices, viz. roundness, boundary smoothness, symmetry, elongation and shape regularity were investigated. The results of this study demonstrated that the visual lobe shapes of subjects elongate horizontally with medium level of roundness, high levels of boundary smoothness, symmetry and regularity for an easy target (O) against a homogeneous background of ‘X’s. When a difficult target (Y) was used, the visual lobes of the subjects were still elongated horizontally but to a smaller extent and with a low level of roundness, medium level of boundary smoothness and regularity and a similar high level of symmetry to the easy target. Moreover, significant correlations between shape indices and visual search time were found, suggesting mathematical models for predicting search time should not merely rely on area but also should consider visual lobe shape indices. Finally, a universal mathematical model containing several visual lobe shape indices was developed, which was applicable in the prediction of visual search time for a range of similar search tasks.     

Visual search tasks: measurement of dynamic visual lobe and relationship with display movement velocity

Visual lobe is a useful tool for predicting visual search performance. Up till now, no study has focused on dynamic visual lobe. This study developed a dynamic visual lobe measurement system (DVLMS) that could effectively map dynamic visual lobe and calculate visual lobe shape indices. The effects of display movement velocity on lobe shape indices were examined under four velocity conditions: 0, 4, 8 and 16 deg/s. In general, with the increase of display movement velocity, visual lobe area and perimeter became smaller, whereas lobe shape roundness, boundary smoothness, symmetry and regularity deteriorated. The elongation index was not affected by velocity. Regression analyses indicated that display movement velocity was important in determining dynamic visual lobe shape indices. Dynamic visual lobe provides another option for better understanding dynamic vision, in addition to dynamic visual acuity. Findings of this study can provide guidelines for analysing and designing dynamic visual tasks.

Practitioner Summary: Dynamic visual lobe is important in reflecting the visual ability of searching for a moving target. We developed a dynamic visual lobe measurement system (DVLMS) and examined display movement velocity’s effects on lobe shape. Findings revealed that velocity was a key factor affecting dynamic visual lobe shape indices.     

More perspectives from Australia

A simulation study of the effects of visual lobe shape and search strategy on search performance is reported. Using a homogeneous pattern search task that did not dictate eye fixation movements (as in reading), three basic categories of strategy and two lobe shapes were tested. Random strategies with controlled overlap of lobe areas, representing various degrees of memory, were found to produce better performance (faster search times with equal or better detection rates) than either a completely random strategy or systematic strategies with various degrees of controlled visual lobe area overlap. The controlled overlap random strategies were far better able to compensate for non-optimum interfixation distances and distortion of visual lobe shape than systematic strategies.     

Age-related changes in visual lobe shape characteristics and their relationship to visual search performance

Visual lobe shape plays an important role in visual search performance, but little is known about the age-related changes in visual lobe shape. The age-related changes in visual lobe shape characteristics and their relationships to visual search performance were investigated in this study. A total of 96 participants aged 15–64 years participated in this study. Their visual lobes were mapped on a uniform 2-D test field composed of 24 regularly spaced meridians passing through the centre of the visual field, and their search performances were also measured. The results showed that in general, age significantly affected visual lobe size, visual lobe shape and search time. As age increased, the visual lobe size decreased; in addition, the roundness, boundary smoothness, symmetry and regularity of the visual lobe deteriorated, and the search time increased. Moreover, significant correlations between visual lobe shape, search time and age were found. Regression analyses indicated that age was important in determining visual lobe shape and search time, suggesting that age differences should be considered when predicting search time and when designing tasks and products that involve visual search in our daily lives and work.     

Visual lobe shape and search performance for targets of different difficulty

In quantitative models of visual search it has usually been assumed that visual lobe area shape was sufficiently regular to be approximated by a circle or ellipse. However, the irregularities in visual lobe shapes that have been found in studies involving extensive lobe mapping have suggested that lobe shape may have important implications for visual search performance and for the accuracy of mathematical models used for performance prediction. However, no systematic research on the relationship between the shape aspect of visual lobes and search performance seems to have been carried out and no comparisons of visual lobe shape characteristics under the effect of target difficulty have been reported. The current study was conducted to achieve two major objectives in two experiments. Experiment 1 used two different targets (letter 'O' and letter 'Y') to map the visual lobes of subjects in order to provide a systematic and quantitative comparison of lobe shape characteristics and experiment 2 was to investigate the correlation of visual lobe shape characteristics with visual search time under the effect of target difficulty. The visual lobes of 28 subjects were mapped on 24 imaginary and regularly spaced meridians originating from the centre of the visual field to resemble the full field mapping situation. Five categories of shape indices, viz. roundness, boundary smoothness, symmetry, elongation and shape regularity were investigated. The results of this study demonstrated that the visual lobe shapes of subjects elongate horizontally with medium level of roundness, high levels of boundary smoothness, symmetry and regularity for an easy target (O) against a homogeneous background of 'X's. When a difficult target (Y) was used, the visual lobes of the subjects were still elongated horizontally but to a smaller extent and with a low level of roundness, medium level of boundary smoothness and regularity and a similar high level of symmetry to the easy target. Moreover, significant correlations between shape indices and visual search time were found, suggesting mathematical models for predicting search time should not merely rely on area but also should consider visual lobe shape indices. Finally, a universal mathematical model containing several visual lobe shape indices was developed, which was applicable in the prediction of visual search time for a range of similar search tasks.     

The Impact of Educational Background on the Effectiveness of Requirements Inspections: An Empirical Study

While the inspection of various software artifacts increases the quality of the end product, the effectiveness of an inspection depends largely on the individual inspectors involved. To address that issue, a large-scale controlled inspection experiment with over 70 professionals was conducted at Microsoft Corporation that focused on the relationship between an inspector's background and their effectiveness during a requirements inspection. The results of the study showed that inspectors with university degrees in majors not related to computer science found significantly more defects than those with degrees in computer science majors. We also observed that level of education (Masters, PhD), prior industrial experience or other job related experiences did not significantly impact the effectiveness of an inspector. The only other type of experience that had a significant impact on effectiveness was experience in writing requirements, i.e. professionals with prior experience writing requirements found statistically significant more defects than their counterparts.     

Effect of display polarity and luminance contrast on visual lobe shape characteristics

The effect of display polarity and luminance contrast on visual lobe (effective visual field) shape characteristics was studied using three levels of luminance contrast with combinations of positive and negative polarities. The binocular effective visual field for a detection task, with a peripherally presented target (V) embedded in a homogeneous competing background (Xs), was mapped on 24 imaginary axes passing through the fixation point. The results showed that visual lobes mapped using positive polarity were statistically larger in area, rounder and more regular in shape than those for negative polarity. The medium contrast condition lobes were more symmetric and regular than low contrast condition lobes, and lobe area and perimeter increased with increasing luminance contrast ratio. Under the interaction of positive polarity and high luminance contrast, visual lobes were found to be larger, smoother and rounder. The high level of luminance and contrast however resulted in a higher degree of visual discomfort. The results indicated that positive polarity and contrast of medium (26:1) to high (41:1) levels are possible display settings for better visual lobe characteristics and better anticipated search performance. Practitioner Summary: The effect of display polarity and luminance contrast on visual lobe shape characteristics was examined with uniform stimulus materials in this study. The results help to identify the optimum display settings for luminance contrast and display polarity to enhance lobe shape characteristics and hence search performance in industrial inspection tasks.     

Simple measures of visual-lobe size and search performance

The objectives of this study were to simplify lobe-size calculation; and to test a simple card-sorting task as a measure of lobe size. A simple method of calculating lobe dimensions from tachistoscopically presented stimuli was found to give results that were comparable to a more complex method using data transformation. A 1 min card-sorting test using only one target against a homogeneous background was shown to be sensitive to subject differences in visual lobe area. With the type of sorting-test material proposed, the whole testing procedure would, at the most, require a 1 min practice period followed by a 1 min test trial. Near foveal acuity was significantly related to horizontal lobe dimensions and to some measures of card-sorting performance. The study showed that a card-sorting task provided a rapid and simple means of estimating relative visual-lobe size.     

基于机器视觉的轨道车辆零部件形位尺寸检测方法研究

在高铁车辆中,包含着种类繁多的零部件,每个零部件对于车辆的正常稳定运行都具有及其重要的影响,传统的检验用时较长且容易出错,检验效率较低。出错的车内装饰部件会造成不同程度的返工,大大的降低了生产效率。目前,高铁零部件形位尺寸检测研究领域尚很少视觉检测相关的研究,针对高铁零部件的大型不固定的特点,提出了完整的视觉检测高铁零部件形位尺寸的方法,首先从Snake动态轮廓模型分割零部件感兴趣区域,之后通过透视投影变换进行空间校正,采用Sauvola局部二值化进行轮廓提取,进而进行零部件视觉形位尺寸测量四个步骤实现高铁零部件的视觉检测,并对高铁上的三种零部件进行测试和验证,实验结果表明,基于视觉的高铁零部件形位尺寸检测具有较好的检测效率和可拓展性,可用于高铁多种零部件的形位尺寸入库检验中。     

Industrial inspection performance depends on both viewing distance and oculomotor characteristics.

The influence of viewing distance and individual differences in the oculomotor resting states (dark vergence and dark focus) on both inspection performance and visual fatigue was investigated by asking 24 college students to perform a visual inspection task for 40 min twice, once with a 20 cm viewing distance and once with a 60 cm viewing distance. During the task participants visually searched enlarged images of contact lenses for six different types of defects. Lens images were presented at a constant visual angle (17.5 degrees) on a CRT. Inspection performance varied significantly across the two viewing distances: participants spent on average more than twice as much time inspecting individual lenses in the near condition (mean = 18.32 s lens(-1)) than in the far condition (mean = 7.25 s lens(-1)). Participants also reported greater visual fatigue in the near condition than in the far condition. At both viewing distances, participants who experienced relatively large inward shifts in dark vergence also tended to be slow inspectors. Neither inspection performance nor measures of fatigue were related to dark focus. These results support existing evidence against the use of near viewing distances and suggest that an oculomotor mechanism links inspection performance and visual fatigue to viewing distance.     

Manual card sorting compared to automatic card presentation for assessing visual lobe size

Abstract

Using a sample of 54 Hong Kong Chinese subjects a highly significant correlation was found between lobe area and search performance on a task where the stimulus presentation was controlled with a semi-automatic electro-mechanical ‘card changer’. By using the same stimulus material for determination of lobe size and search performance and by reducing the possibility of subjects using extreme search strategies, a 90s manual card sorting test was found to correlate significantly with the ‘card changer’ results and with lobe area. The good correlation with lobe area was obtained for a homogeneous group of subjects with respect to age and near acuity using a rapid and simple method of lobe area measurement. The visual lobe is a function of considerable importance for visual search and has been shown to be related to search performance in a variety of practical situations. It is suggested here that a card sorting task may be used to assess the relative extent of a person's visual lobe size for screening individuals involved in search tasks, or to assess the effects of training.     

Perspective-based Usability Inspection: An Empirical Validation of Efficacy

Inspection is a fundamental means of achieving software usability. Past research showed that the current usability inspection techniques were rather ineffective. We developed perspective-based usability inspection, which divides the large variety of usability issues along different perspectives and focuses each inspection session on one perspective. We conducted a controlled experiment to study its effectiveness, using a post-test only control group experimental design, with 24 professionals as subjects. The control group used heuristic evaluation, which is the most popular technique for usability inspection. The experimental design and the results are presented, which show that inspectors applying perspective-based inspection not only found more usability problems related to their assigned perspectives, but also found more overall problems. Perspective-based inspection was shown to be more effective for the aggregated results of multiple inspectors, finding about 30% more usability problems for 3 inspectors. A management implication of this study is that assigning inspectors more specific responsibilities leads to higher performance. Internal and external threats to validity are discussed to help better interpret the results and to guide future empirical studies.     

Improving SEM Inspection Performance in Semiconductor Manufacturing Industry

Scanning electron microscope (SEM) station is one of the major quality control tasks in wafer manufacturing process. During the process of examining defects on a screen for a certain period of time, SEM inspectors frequently complain about visual fatigue problems. The purpose of the study was to evaluate the effect of wafer‐coating condition (noncoating treatment and gold‐coating treatment) and liquid crystal display (LCD) monitor size (14‐inch and 19‐inch monitor) from the aspects of objective visual fatigue measures (NPA and CFF), subjective eye fatigue rating, and inspection performance. Twelve SEM inspectors participated in this experiment. The results indicated that the treatment of gold‐coating wafer showed significant difference on reducing objective visual fatigue in NPA and CFF change. Using a 19‐inch LCD monitor also demonstrated the effect on reducing eye fatigue as well as improving inspection performance. The improvement of using a gold‐coating treatment wafer and a 19‐inch LCD monitor to reduce SEM inspectors' visual fatigue and to increase inspection performance is thus recommended. © 2012 Wiley Periodicals, Inc.     

Using virtual reality technology for aircraft visual inspection training: presence and comparison studies

The aircraft maintenance industry is a complex system consisting of several interrelated human and machine components. Recognizing this, the Federal Aviation Administration (FAA) has pursued human factors related research. In the maintenance arena the research has focused on the aircraft inspection process and the aircraft inspector. Training has been identified as the primary intervention strategy to improve the quality and reliability of aircraft inspection. If training is to be successful, it is critical that we provide aircraft inspectors with appropriate training tools and environment. In response to this need, the paper outlines the development of a virtual reality (VR) system for aircraft inspection training.

VR has generated much excitement but little formal proof that it is useful. However, since VR interfaces are difficult and expensive to build, the computer graphics community needs to be able to predict which applications will benefit from VR. To address this important issue, this research measured the degree of immersion and presence felt by subjects in a virtual environment simulator. Specifically, it conducted two controlled studies using the VR system developed for visual inspection task of an aft-cargo bay at the VR Lab of Clemson University. Beyond assembling the visual inspection virtual environment, a significant goal of this project was to explore subjective presence as it affects task performance. The results of this study indicated that the system scored high on the issues related to the degree of presence felt by the subjects. As a next logical step, this study, then, compared VR to an existing PC-based aircraft inspection simulator. The results showed that the VR system was better and preferred over the PC-based training tool.     

The correlation between visual fatigue and duration of viewing as assessed by brain monitoring

Duration of viewing was considered as one of the most important factors of 3D visual fatigue. However, their relationship was not well studied. We proposed to use brain monitoring techniques to reveal more details about the variety of brain activity while watching three‐dimensional (3D) content. We investigated the spectral patterns in the electroencephalogram related to various duration of viewing and showed the power spectral density varied significantly along with the development of fatigue over occipital lobe, parietal lobe, and right frontal lobe. Moreover, we first described the trend of brain activity during 3D content viewing and revealed the location of significant components related to 3D visual fatigue. We believe that the absolute power describes more information and may be a better indicator of 3D visual fatigue assessment compared with relative power. We also first revealed the cortex location that is related to 3D visual fatigue. Our findings may help to define appropriate electroencephalogram features for online 3D visual fatigue detection while participants viewing 3D content.     

Evaluation of best system performance: Human,automated, and hybrid inspection systems

Recently, 100% inspection with automated systems has seen more frequent application than traditional sampling inspection with human inspectors. Nevertheless, humans still outperform machines in most attribute inspection tasks. Because neither humans nor automation can achieve superior inspection system performance, hybrid inspection systems where humans work cooperatively with machines merit study. In response to this situation, this research was conducted to evaluate three of the following different inspection systems: (1) a human inspection system, (2) a computer search/human decision‐making inspection system, and (3) a human/computer share search/decision‐making inspection system. Results from this study showed that the human/computer share search/decision‐making system achieve the best system performance, suggesting that both should be used in the inspection tasks rather than either alone. Furthermore, this study looked at the interaction between human inspectors and computers, specifically the effect of system response bias on inspection quality performance. These results revealed that the risky system was the best in terms of accuracy measures. Although this study demonstrated how recent advances in computer technology have modified previously prescribed notions about function allocation alternatives in a hybrid inspection environment, the adaptability of humans was again demonstrated, indicating that they will continue to play a vital role in future hybrid systems. © 2003 Wiley Periodicals, Inc. Hum Factors Man 13: 137–152, 2003.     

ON THE ACCURACY OF INSPECTORS

Reasons for inspector inaccuracy have been examined in three main groups: reasons of basic individual abilities; of formal organization (training, instructions, physical conditions, the lay-out of the job); and of interpersonal relations and social relations. Without denying the importance of the basic individual abilities of inspectors, which must set the ultimate limits of accuracy, it seems that the actual limits in a working situation are set by the other two groups of reasons. These practical limits may be well inside the limits set by basic psychological and physiological functions. For example, given an inspector who is well equipped with the basic abilities and aptitudes for the actual inspection task itself, he cannot operate more accurately than his instructions, for instance, allow him to. Moreover, even if well selected, well trained and well briefed, he still can be no more accurate than the pressures of interpersonal and other social relations permit. These interpersonal relations do not necessarily make him pass work that should be failed; they may also make him fail work that should be passed. Conversely, the production man will be more eager to ‘ get products past ’, to trick the inspector, when he does not‘ sanction ’ the inspector. This may in turn make the inspector reject more of the work of the man who tries to trick him than is actually bad. These interpersonal and social relations become all the more important when the inspection task is the more ‘ socio-technical ’—involving direct interaction with production.

It seems that when relations between production and inspection are poor. when production feel they can not sanction the inspectors and/or their standards, and when inspection chooses to play its role in a dominant, authoritative, and essentially invidious way. rather than as finding neutral facts, then not only will inspector accuracy be adversely affected, but there will also be strong pressures against inspection supervisors testing their inspector's accuracy.

Although the obvious man to check inspector accuracy is the inspector's own supervisor, there are powerful pressures against his doing this,Not only are there practical difficulties, but also there is the fact that inspection supervisors, and others, tend to become ‘ product-bound ’, even to the neglect of their true supervisory duties. Moreover, the pressures of interdepartmental relations encourage inspection supervisors to see themselves first as inspectors, and only secondarily as supervisors.

The general conclusion is that inspector accuracy, in a working situation, is determined by a wide range of factors. Problems of inaccuracy must then be studied in a wider context than is given by any single approach.     

UAV imagery based potential safety hazard evaluation for high-speed railroad using Real-time instance segmentation

Potential safety hazards (PSHs) along the track needs to be inspected and evaluated regularly to ensure a safe environment for high-speed railroad operations. Other than track inspection, evaluating potential safety hazards in the nearby areas often requires inspectors to patrol along the track and visually identify potential threads to the train operation. The current visual inspection approach is very time-consuming and may raise safety concerns for the inspectors, especially in remote areas. Using the unmanned aerial vehicle (UAV) has great potential to complement the visual inspection by providing a better view from the top and ease the safety concerns in many cases. This study develops an automatic PSH detection framework named YOLARC (You Only Look at Railroad Coefficients) using UAV imagery for high-speed railroad monitoring. First, YOLARC is equipped with a new backbone having multiple available receptive fields to strengthen the multi-scale representation capability at a granular level and enrich the semantic information in the feature space. Then, the system integrates the abundant semantic features at different high-level layers by a light weighted feature pyramid network (FPN) with multi-scale pyramidal architecture and a Protonet with residual structure to precisely predict the track areas and PSHs. A hazard level evaluation (HLE) method, which calculates the distance between identified PSH and the track, is also developed and integrated for quantifying the hazard level. Experiments conducted on the UAV imagery of high-speed railroad dataset show the proposed system can quickly and effectively turn UAV images into useful information with a high detection rate and processing speed.     

To reduce side lobe level of slotted array antennas using nonuniform waveguides

In this article, a method is presented to reduce the side lobe level of slotted waveguide array antennas while the gain to be constant. In this method, the H‐plane dimension of the waveguide is considered as the variable rather than constant. The nonuniformity of waveguide walls obviates the need for offset of slots and thereby reduces the side lobe level of radiation pattern. A slotted nonuniform waveguide is designed at frequency 10 GHz and then fabricated and tested. © 2015 The Authors International Journal of RF and Microwave Computer‐Aided Engineering Published by Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:42–46, 2016.