The development and application of a multiple wavelength illumination technique for the vision-based process monitoring of aero-structure riveting

Airframe riveting is a critical process that requires high levels of process monitoring and quality assurance due to the very high risk associated with the failure of such joints. This paper describes the development of the enabling technology developed for a machine vision-based process monitoring system. One of the key factors affecting the performance of a machine vision system is the quality of the lighting. In the application described in this paper the available lighting was severely limited by the confined space in which the system had to operate. The problem was also compounded by the reflective nature of the objects to be examined. The initial images obtained were not suitable for further processing due to the presence of significant shadows and specular reflections. A novel solution to this problem based on multiple wavelength illumination and signal processing is presented along with results from experimental trials of the approach.     

照亮都市空间的光纤之美

光导纤维如今已广泛应用于现代社会的各个领域,它不但适用于通信、医学、传感器等科学应用领域,缤纷的都市空间更是展现光纤之美的重要舞台。本文主要介绍了西方发达国家在城市建筑照明、室内照明、景观与公共艺术照明等诸多城市空间领域光导纤维的应用情况,旨在为丰富我国的城市空间提供一些有益的参考,并由此倡导光纤照明这样一种绿色、安全、时尚的城市照明方式。进而为其将来更好地服务于现代社会,提升城市生活品质做好理论与实践两方面的充分准备。     

小议灯光在室内餐厅设计中的运用

近年来,随着人们物质与精神生活水平的提高,对照明环境的质量也提出了越来越高的要求,室内灯光设计也越来越受到人们的关注。合理的室内灯光设计,能够营造一个格调高雅温馨的家居环境,为室内装修设计画上点睛之笔。本文概括介绍了室内灯光设计及其发展趋势,分析了室内灯光设计在餐厅照明中的应用,旨在对今后室内灯光设计工作的发展能够有所启迪。     

Optimal maintenance planning for sustainable energy efficiency lighting retrofit projects by a control system approach

The energy savings achieved by implementing energy efficiency (EE) lighting retrofit projects are sometimes not sustainable and vanish rapidly given that lamp population decays as time goes by if without proper maintenance activities. Scope of maintenance activities refers to replacements of failed lamps due to nonrepairable lamp burnouts. Full replacements of all the failed lamps during each maintenance interval contribute to a tight project budget due to the expense for the lamp failure inspections, as well as the procurement and installation of new lamps. Since neither “no maintenance” nor “full maintenance” is preferable to the EE lighting project developers (PDs), we propose to design an optimal maintenance plan that optimises the number of replacements of the failed lamps, such that the EE lighting project achieves sustainable performance in terms of energy savings whereas the PDs obtain their maximum benefits in the sense of cost–benefit ratio. This optimal maintenance planning (OMP) problem is aptly formulated as an optimal control problem under control system framework, and solved by a model predictive control (MPC) approach. An optimal maintenance plan for an EE lighting retrofit project is designed as a case study to illustrate the effectiveness of the proposed control system approach.     

Stereo Light Probe

In this paper we present a practical, simple and robust method to acquire the spatially‐varying illumination of a real‐world scene. The basic idea of the proposed method is to acquire the radiance distribution of the scene using high‐dynamic range images of two reflective balls. The use of two light probes instead of a single one allows to estimate, not only the direction and intensity of the light sources, but also the actual position in space of the light sources. To robustly achieve this goal we first rectify the two input spherical images, then, using a region‐based stereo matching algorithm, we establish correspondences and compute the position of each light. The radiance distribution so obtained can be used for augmented reality applications, photo‐realistic rendering and accurate reflectance properties estimation. The accuracy and the effectiveness of the method have been tested by measuring the computed light position and rendering synthetic version of a real object in the same scene. The comparison with standard method that uses a simple spherical lighting environment is also shown.     

Will musculoskeletal and visual stress change when Visual Display Unit (VDU) operators move from small offices to an ergonomically optimized office landscape?

This study investigated the effect of moving from small offices to a landscape environment for 19 Visual Display Unit (VDU) operators at Alcatel Denmark AS. The operators reported significantly improved lighting condition and glare situation. Further, visual discomfort was also significantly reduced on a Visual Analogue Scale (VAS). There was no significant correlation between lighting condition and visual discomfort neither in the small offices nor in the office landscape. However, visual discomfort correlated significantly with glare in small offices i.e. more glare is related to more visual discomfort. This correlation disappeared after the lighting system in the office landscape had been improved. There was also a significant correlation between glare and itching of the eyes as well as blurred vision in the small offices, i.e. more glare more visual symptoms. Experience of pain was found to reduce the subjective assessment of work capacity during VDU tasks. There was a significant correlation between visual discomfort and reduced work capacity in small offices and in the office landscape. When moving from the small offices to the office landscape, there was a significant reduction in headache as well as back pain. No significant changes in pain intensity in the neck, shoulder, forearm, and wrist/hand were observed.The pain levels in different body areas were significantly correlated with subjective assessment of reduced work capacity in small offices and in the office landscape.By careful design and construction of an office landscape with regard to lighting and visual conditions, transfer from small offices may be acceptable from a visual-ergonomic point of view.     

Visual effects of the luminance surrounding a computer display

The luminance surrounding a computer display can potentially reduce visibility of the display (disability glare), result in sensations of discomfort (discomfort glare) and result in transient adaptation effects from fixating back and forth between the two luminance levels. The study objective was to measure the effects of surround luminance levels upon these functions in younger and older adults to determine recommended surround luminance levels. The younger age group comprised 20 subjects (mean age 27.9 years, range 23 – 39) and the older group 17 subjects (mean age 55.5 years, range 47 – 63). The central task was presented with luminance of 91 cd/M², tested surround luminance levels were 1.4, 2.4, 8.9, 25.5, 50, 91, 175, 317, and 600 cd/M². Disability glare was tested with low contrast (20%) visual acuity charts, transient adaptation was tested with a task that required regular fixation between the two luminance levels, discomfort was measured with a questionnaire after reading stories with different surround luminance levels, and preferred luminance was measured by method of adjustment. The surround luminance significantly affected transient adaptation (p < 0.0001), optimal performance occurred at 50 cd/M² and above for the young group and at 91 cd/M² and above for the older group. Neither low contrast acuity (disability glare) nor symptoms when reading were significantly affected by surround luminance. There was wide variation in preferred surround luminance; however, average preferred surround luminance was 86.9 cd/M² for the young group and 62.2 cd/M² for the older group, slightly below the central luminance of 91 cd/M². The effects of the surround luminance within the tested range are not large; however, the data show that the lowest surround luminance levels should be avoided and that surround luminance levels at or slightly below that of the central task are preferred.     

I-bus智能照明系统在轨道交通中的应用

针对轨道交通中传统的照明控制方式的不足,简单介绍了智能照明系统的概念和特点,并详细说明了I-bus智能建筑控制系统的工作原理,构成、功能及其优势.具体阐述了I-bus智能建筑控制系统在轨道交通照明系统中的具体应用方案,从而实现轨道交通照明系统的智能化运营.     

西安长安互通立交桥景观照明设计

通过介绍西安长安立交桥的照明方式及表现手法，强调人、物、文化一体化的景观照明的设计思想和展现的艺术特色。     

英语教学中的美育渗透

本文从仪态美、语音、语凋美、板书美和表达美四个方面论述了大学英语教学中的美育渗透，从美学、心理学的角度论证了美育对教师提出了新的挑战。