A vision for natural photonics

The structural colours of animals have provided an attractive means of marketing for those reflectors designed and manufactured by humans. Over the past 30 years, optics well known to the physicist have emerged, example after example, in nature. But now the tables are turning and animals are becoming the first stage in the optical design process. Biologists and physicists have begun collaborative optics-based projects where the data will be supplied by nature. The real trigger of this surge in interest is the recent identification of 'photonic crystals' in animals. Animals, it would seem, have plenty to teach us, not only in terms of the design of their optical structures, but also their engineering. A familiar message, perhaps, except now action is underway.     

基于机器人听觉和视觉的目标搜索策略

提出了一种运用行为规则库和综合使用听觉信息、视觉信息来完成目标搜索的策略.该策略首先由机器人的传声器阵列和双目立体视觉摄像机采集环境信息,然后通过行为控制中心决定执行规则库中的动作完成目标搜索,从而避免使用机器人的单一感官信息造成的难题.行为规则库由4条和机器人听觉模块和视觉模块相关的规则组成.听觉模块基于五元传声器阵...     

A heuristic for formulating within-plant manufacturing focus

The concept of manufacturing focus suggests that each plant is assigned a unique set of manufacturing tasks derived from the firm's competitive strategy. Many empirical studies have verified the importance and benefits of manufacturing focus in enhancing a firm's competence in the market. Nonetheless there is no methodology offered for designing such a manufacturing system with considerations of resource requirements although the need has been recognized. In this study, we propose a methodology that can help managers arrive at a manufacturing focus design within a plant. Because of the large size and nonlinear nature of the problem, a heuristic solution is proposed. The heuristic translates the strategic concept of competitive priorities into management parameters, thereby allowing incorporation of market factors into manufacturing process design. Experimental results show that the proposed methodology offers managers the opportunity to generate and assess alternative focus designs which are otherwise unavailable. The use of the heuristic is straightforward in practical situations and should greatly facilitate the achievement of manufacturing focus with minimal resource requirements. Overall, this research provides an analytical framework for further research in focused manufacturing.     

基于灰度的亚像素插值视觉测量方法

针对现有视觉测量中的检测代价高,精度低和速度慢问题,该文提出一种基于计算机机器视觉的紧密内插值亚像素测量方法。该方法基于线性插值算法的原理,结合常规边缘检测方法和图像的灰度曲线图,利用阈值分割和标准长度进行亚像素自适应阈值选择。为验证该方法的有效性,对标准量块长度进行测量实验,并分析测量系统的误差影响因素。相比于传统的Canny算子方法检测结果,该方法的平均测量准确度提升46.2%。实验结果表明该算法的测量精度较高,可以快速、精确地测量出物体的几何尺寸。     

基于机器视觉的自动扶梯梯级测速方法

针对自动扶梯运行速度的检测,提出一种基于机器视觉的自动扶梯梯级测速方法。首先,对机器视觉系统采集得到的梯级运行图像进行一系列的预处理,通过设置阈值实现目标颜色的识别;然后,采用直线扫描法对颜色提取后的不连通区域进行填充,对得到的二值图像进行边缘检测与轮廓识别,返回轮廓面积最大的图像;最后,提取每张图像中黄色区域右边界直线起始端点的横坐标,通过差分法计算得到梯级的速度。结果表明,该方法实现了非接触测量并且能够得到较为准确的检测结果。     

A complex carotenoid palette tunes avian colour vision

The brilliantly coloured cone oil droplets of the avian retina function as long-pass cut-off filters that tune the spectral sensitivity of the photoreceptors and are hypothesized to enhance colour discrimination and improve colour constancy. Although it has long been known that these droplets are pigmented with carotenoids, their precise composition has remained uncertain owing to the technical challenges of measuring these very small, dense and highly refractile optical organelles. In this study, we integrated results from high-performance liquid chromatography, hyperspectral microscopy and microspectrophotometry to obtain a comprehensive understanding of oil droplet carotenoid pigmentation in the chicken (Gallus gallus). We find that each of the four carotenoid-containing droplet types consists of a complex mixture of carotenoids, with a single predominant carotenoid determining the wavelength of the spectral filtering cut-off. Consistent with previous reports, we find that the predominant carotenoid type in the oil droplets of long-wavelength-sensitive, medium-wavelength-sensitive and short-wavelength-sensitive type 2 cones are astaxanthin, zeaxanthin and galloxanthin, respectively. In addition, the oil droplet of the principal member of the double cone contains a mixture of galloxanthin and two hydroxycarotenoids (lutein and zeaxanthin). Short-wavelength-absorbing apocarotenoids are present in all of the droplet types, providing filtering of light in a region of the spectrum where filtering by hydroxy- and ketocarotenoids may be incomplete. Thus, birds rely on a complex palette of carotenoid pigments within their cone oil droplets to achieve finely tuned spectral filtering.     

A longitudinal study of the impact of market requirements focus on manufacturing performance

This paper examines the longitudinal relationship between market requirements focus and manufacturing performance in a sample of automotive supplier plants. Statistical analysis indicates that, overall, an increase in market requirements focus from 1995 to 1999 was associated with an increase in manufacturing performance over the same time period, while a decrease in focus was associated with decreasing performance. Furthermore, plant manager interviews suggest that plant-level involvement and firm resource commitment may serve to leverage focus improvement efforts, or moderate the negative effects of decreasing focus.     

Image focus volume enhancement in shape from focus systems

Three-dimensional object reconstructions is an active research area in digital imaging. In shape from focus approach, erroneous focus measurements result in inaccuracy in the depth map reconstruction of 2D object. Conventionally, to enhance the image focus volume, focus values are aggregated within a window, which is a linear filtering approach. Owing to the inherent limitation of linear process, optimal results may not be obtained. In order to overcome this limitation, a non-linear filtering approach is proposed to enhance the image focus volume for accurate depth estimation. The noisy focus values are restored in two steps. First, noisy focus values are detected using min–max operators. In order to increase the dynamic range between the minimum and the maximum focus values within the window, an appropriate power law function is designed. In second step, only the noisy measurements are replaced with the estimated ones. A refined depth map is obtained from the updated focus volume. This process continues until the difference between the previous and the current depth maps becomes very small. The performance of the proposed non-linear filtering approach is obtained for various synthetic and real objects. The results highlight the depth map estimates of the proposed approach more accurate while preserving object edges. Comparative analysis demonstrates the effectiveness of the proposed approach.     

A vision of true costing [renewable energy]

In recent years, most new generating plant installed in the UK electricity supply industry has been gas turbine. In the near future, this trend could change as both environmental pressures and international agreements legislate towards a significant increase in the level of exploitation of renewable energy. Options for new generating plant must be assessed and compared using several bases before a choice is made. This paper describes the initial stages of development of techniques to accommodate externalities into the decision-making process. An illustrative example, wind energy, is presented     

基于机器视觉的罐盖缺陷检测

根据金属材质罐盖制造中生产线上的工作环境和检测要求,针对目前生产线上人工检测的速度慢、效率低、准确率不高等缺点,提出了一种基于计算机视觉的罐盖缺陷检测算法,可快速准确地实现生产线上的金属罐盖的缺陷检测.具体做法是综合一系列图像处理算法,对罐盖罐口、注胶区域、内圆区域等三个主要区域进行检测.结果表明,缺陷检测的速度可达到每秒10个,从而为罐盖的缺陷生产线在线检测提供了很好的支持.     

Maoris in focus

Abstract

The virtually simultaneous announcement of the invention of photography in Paris and London in January 1839 marks the “official” birthday of the new technology. The reception given to this announcement in the course of that year, and the subsequent diffusion of knowledge and practice of the technology, show significant differences from country to country. These differences in impact and the rate of take-up may have depended on such factors as the country's proximity to the key events, its level of intellectual openness and general economic development, as well as the ex~stence of key individuals — businessmen and scientists — willing to experiment in the untried processes out of sheer curiosity or for personal gain.     

Passive focus sensor

A focus-sensor module for large-format photographic cameras has been developed that permits the measurement of defocus at any location of interest in the image field. The focus sensor employs passive triangulation through a split imaging aperture. The main difference between commercial autofocus modules with fixed-measurement positions and the new module is that the imaging aperture is subdivided into more than two fields to compensate for the unknown location of the defocus measurement.

At ?/5.6 the focus sensor shows a maximum resolution in defocus of approximately 0.1mm at the image side at levels of illuminance in the recording plane ≥0.01 lx.

     

A CMOS smart pixel for active 3-D vision applications

A CMOS smart pixel aimed at three-dimensional vision applications is introduced. It is suitable for scannerless laser ranging systems which employ the indirect time-of-flight measuring technique to recover distance information. The pixel is operated with trains of light pulses generated by an external source to illuminate the scene and contains most of the processing electronics to perform signal accumulation and noise reduction operations. The smart pixel architecture includes an N-well photodiode plus a self-biasing voltage amplifier and a switched-capacitor fully differential stage. The pixel is fabricated in standard CMOS 0.6 /spl mu/m technology and measures 180/spl times/160 /spl mu/m/sup 2/ (including the photodiode) with a fill factor of 14%. Electrooptical test results confirm the smart pixel functionality in a range of distance from 3 m to 9 m, and the accuracy achieved for preliminary distance measurements is 15 cm. Both the accuracy and the extension of the range of distance are supposed to be improved by reducing setup and environmental noise contributions that limit the pixel performance.     

A multinomial choice model approach for dynamic driver vision transitions

Exploring the continual process of drivers allocating their attention under varying conditions could be vital for preventing motor vehicle crashes. This study aims to model visual behaviors and to estimate the effects of various contributing factors on driver’s vision transitions. A visual attention allocation framework, based on certain contributing attributes related to driving tasks and environmental conditions, has been developed. The associated logit type models for determining driver choices for focal points were successfully formulated and estimated by using naturalistic glance data from the 100-car event database. The results offer insights into driver visual behavior and patterns of visual attention allocation. The three focal points that drivers most frequently rely on and glance at are the forward, left and rear view mirror. The sample drivers were less likely to demonstrate troublesome transition patterns, particularly in mentally demanding situations. Additionally, instead of shifting vision directly between two non-forward focal points, the sample drivers frequently had an intermediate forward glance. Thus, seemingly unrelated paths could be grouped into explanatory patterns of driver attention allocation. Finally, in addition to the vision-transition patterns, the potential pitfalls of such patterns and possible countermeasures to improving safety are illustrated, focusing on situations when drivers are distracted, traveling at high speeds and approaching intersections.