彩色等离子体显示器的新进展

扼要地介绍了近年来世界上各大公司对彩色PDP的结构和驱动方法的改进 ,将现今彩色PDP的亮度、对比度和色纯度等主要性能与过去相比 ,得到明显的改善 ,达到了与高清晰度CRT相当的性能。     

海表面盐度卫星微波遥感研究进展

海表面盐度SSS(Sea Surface Salinity)是研究大洋环流和海洋对全球气候影响的重要参量、是决定海水基本性质的重要因素之一。卫星微波遥感可以满足盐度研究过程中大范围、连续观测的需要,国际上统一的认识是选择频率为1.413 GHz的L波段作为盐度遥感的首选波段。目前,国外发展的海面盐度微波遥感反演算法主要有两种:基于海表发射率估算海表盐度的算法和基于贝叶斯定理提出的反演算法。影响盐度反演精度的因素主要有太空辐射、电离层法拉第旋转、大气、海面粗糙度等。其中,海面粗糙度对盐度反演影响很大,海面粗糙度处理模型可以分为3大类:理论算法(间接发射率模型、直接发射率模型)、经验算法、半经验半理论算法(Hollinger 半经验模型、WISE半经验模型、Gabarró模型)。SMOS卫星和Aquarius/SAC\|D卫星的成功发射,将海表面盐度遥感的反演精度控制在0.2 psu以内,通过改进反演算法,有望得到更高的反演精度。     

Brightness and contrast do not affect visually induced motion sickness in a passively-flown fixed-base flight simulator

BackgroundVisually Induced Motion Sickness (VIMS) or simulator sickness is often elicited by a visual stimulus that lacks the appropriate vestibular or proprioceptive feedback. In this study, we chose to investigate the effects of brightness and contrast of the visual scene on VIMS.HypothesisWe hypothesized that visual environments differing in brightness or contrast would differentially induce VIMS. The symptoms of VIMS should be most severe for the combination of high brightness and high contrast and conversely lowest for the low brightness and low contrast condition.Methods33 healthy subjects were tested in a fixed-base flight simulator. Each subject flew in four consecutive but counterbalanced conditions during one large experimental session. The four conditions consisted of identical recorded flight paths, differing only in brightness and contrast in a fully crossed design. VIMS was assessed with the Simulator Sickness Questionnaire and the Fast Motion Sickness scale administered during and after each condition. Postural Sway (PS) was measured after each condition.ResultsAll four brightness and contrast conditions were found to be effective in that they increased PS and elicited moderate VIMS. However, there were no main or interaction effects for brightness or contrast.ConclusionsOur findings suggest that brightness and contrast do not modulate the induction of VIMS. This conclusion may be limited to moderately provocative stimuli.     

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.     

电子储存环的红外边缘辐射

介绍了电子储存环中偏转磁铁入口和出口处的非均匀磁场产生的辐射——边缘辐射，给出了零边缘长度、有限边缘长度、有限直线节长度条件下的辐射通量和亮度分布，通过与常规同步辐射场的比较，充分说明了边缘辐射是一种优良的红外同步辐射光源。     

Segment dependent dynamic multi-histogram equalization for image contrast enhancement

Histogram equalization (HE) method proved to be a simple and most effective technique for contrast enhancement of digital images. However it does not preserve the brightness and natural appearance of the images, which is a major drawback. To overcome this limitation, several Bi- and Multi-HE methods have been proposed. Although the Bi-HE methods significantly enhance the contrast and may preserve the brightness, the natural appearance of the images is not preserved as these methods suffer with the problem of intensity saturation. While Multi-HE methods are proposed to further maintain the brightness and natural appearance of images, but at the cost of contrast enhancement. In this paper, two novel Multi-HE methods for contrast enhancement of natural images, while preserving the brightness and natural appearance of the images, have been proposed. The technique involves decomposing the histogram of an input image into multiple segments based on mean or median values as thresholds. The narrow range segments are identified and are allocated full dynamic range before applying HE to each segment independently. Finally the combined equalized histogram is normalized to avoid the saturation of intensities and un-even distribution of bins. Simulation results show that, for the variety of test images (120 images) the proposed method enhances contrast while preserving brightness and natural appearance and outperforms contemporary methods both qualitatively and quantitatively. The statistical consistency of results has also been verified through ANOVA statistical tool.     

室内照明技术探讨

论述了一般室内照明设计的目的和要求，并分别对各照明设计要素进行了分析，有利于更好地理解掌握照明技术和照明标准，提高照明设计水平。     

新型X型射线影像增强系统分辨率数学模型

课题组设计了新型的X射线影像增强系统。由于它是由多个光电器件级联而成的链状成像系统,在组成器件之间存在着一定的分辨率函数关系,并且这种函数关系会随着成像视野的变化而变化．鉴于此种关系,建立了系统的分辨率数学模型,对多种器件组合效果进行理论分析。结果表明分辨率理论计算值和实验测量值比较吻合,所以分辨率数学模型节省了系统的设计时间和费用,对提高系统分辨率起着理论指导作用。     

从禅宗到迷宫般的沉醉：圆明园狮子林与苏州狮子林的历史与美学交往

18世纪后期,清高宗乾隆帝在北京圆明园的长春园北侧建造狮子林和西洋楼两处园林。他的狮子林仿建了以假山迷宫闻名的苏州名园狮子林,而西洋楼包含着一个巴洛克式迷宫与错觉透视的戏台。通过对元代至清代有关2个狮子林园的诗词和园记的现象学感知分析与历史诠释学解读,揭示了苏州狮子林园从元代的禅宗空间到明代的幻境,再到清代的沉醉迷宫的美学变迁,以及其对当代精神空间塑造的历史启迪与文化含义。     

多光谱扫描仪遥感测量海冰图象中亮度与厚度关系研究

本文利用海冰分类图象,以海冰厚度、波长和反射率之间建立的模型为理论基础,通过对海冰样区大量统计运算及各种回归结果的比较,导出了多光谱扫描仪3、4、5、6四个波段海冰亮度灰级与海冰厚度的关系式,利用这一关系式算出的海冰样区的冰厚分布数值图具有直观、定量的特点。