Background and foreground interaction: Influence of complementary colors on the search task

Labels are indispensable visual (communication) elements that completely deliver the geospatial message of maps. The objective of this study is to investigate the impact of complementary colors between the map's background and text on the readability of cartographic texts and thus on the efficiency of the map user's search task. This is compared with the use of the “traditional” black labels on the corresponding colored backgrounds. Furthermore, a number of user characteristics, such as gender and expertise, are taken into account as well. The users' eye movements were registered to study their attentive behavior during the visual search task. In addition to the complement of the color's hue, the analyses were based on the difference in luminance, which could also affect the labels' readability. The difference between the black and colored label design was significantly different versus the eye‐tracking metrics. A correlation was found between the color difference and reaction time measurement and between the luminance difference and fixation duration. © 2014 Wiley Periodicals, Inc. Col Res Appl, 40, 437–445, 2015     

Further investigation on the modified hyperbolic function in the CAM16 color appearance model

In the International Commission on Illumination (CIE) color appearance model CIECAM02, a modified hyperbolic function is used to represent luminance adaptation. The same nonlinear function is also used in the new color appearance model CAM16 [Color Res Appl., 2017;42:703‐718]. Although the modified hyperbolic function seems reasonable based on physiological evidence, it has an infinite slope at the origin, which causes instability for both the forward and inverse modes of the CIECAM02/CAM16 models. In this article, various possible extensions to the nonlinear luminance adaptation function in CIECAM02/CAM16 are reviewed and evaluated. Based on these investigations, the Gill extension to the hyperbolic function that is used to represent luminance adaptation [Proceedings of 16th Color and Imaging Conference, pp. 327‐331, 2008], is recommended at both the lower end (q < q_L ) and the upper end (q > q_U ), where q is the appropriate R_c , G_c , B_c (or R_wc , G_wc , B_wc ) response. In addition, the new recommended function can be readily inverted for use in the appropriate inverse appearance model. From an extensive analysis using available experimental data sets, we also propose that, for the lower and upper limits of the luminance range in the extended model, the values q_L = 0.26 and q_U = 150 be used, respectively.     

A simplified procedure for determining indoor daylight illuminance using daylight coefficient concept

The first step in evaluating the visual performance and energy efficiency provided by daylight requires an accurate estimation of the amount of daylight entering a building. The actual daylight illuminance of a room is mainly influenced by the luminance levels and patterns of the sky in the direction of view of the window at that time. The daylight coefficient concept, which considers the changes in the luminance of the sky elements, offers a more effective way of computing indoor daylight illuminances. Recently, Kittler et al. have proposed a new range of 15 standard sky luminance distributions including the CIE (International Commission on Illumination) standard clear sky. Lately, these 15 sky luminance models have been adopted as the CIE Standard General Skies. This paper presents a graphical method to calculate interior illuminance for the CIE standard clear sky using the daylight coefficient approach. The simplified techniques in the form of a nomograph and Waldram diagram were established and described. The performance of the proposed approach was evaluated against the results obtained by an independent calculation approach and a computer simulation program. It was shown that the daylight illuminances estimated by our graphical tool were in reasonably good agreement with those produced from the other two methods. The findings provide building professionals and students a reliable and simple alternative that incorporates the daylight coefficient concept to estimate the interior daylight illuminance and assess daylighting performance.     

红外辐射测量系统外场标定方法及飞行目标亮度反演方法

对于外场红外辐射特性测量设备,标定建立了输出灰度和输入能量之间的对应关系。通过构建中心红外系统外场标定体系,分析了直接扩展源标定、间接扩展源标定、小面元黑体近距离成像标定的能量传递过程、标定试验过程以及3种标定方法得到的系统响应度和系统底灰度的物理含义,指出了它们的相同和不同之处,进行了一致性分析。给出了采用标定数据计算飞行目标亮度的方法并提出了中距离外场红外辐射测量实验方法,对大气透过率软件和标定方法进行验证。     

像增强器在高速图像采集中的应用分析

对以9350EOS-3-PRO三代像增强器和MC1362高速相机为平台搭建的高速采集系统进行了简单介绍,对可能影响像增强器工作的外部因素进行了实验分析。从电压和照度两个方面出发,通过实验采集数据并用MATLAB软件处理后得到结果。分析结果表明,当电压在2.98 V~4.22 V之间时,成像效果无明显变化,但在低照度环境下能显著提高成像效果,在高照度环境下工作容易饱和,有待进一步改善     

Discomfort luminance level of head-mounted displays depending on the adapting luminance

The Images in an immersive head-mounted display (HMD) for virtual reality provide the sole source for visual adaptation. Thus, significant, near-instantaneous increases in luminance while viewing an HMD can result in visual discomfort. Therefore, the current study investigated the luminance change necessary to induce this discomfort. Based on the psychophysical experiment data collected from 10 subjects, a prediction model was derived using four complex images and one neutral image, with four to six levels of average scene luminance. Result showed that maximum area luminance has a significant correlation with the discomfort luminance level than average, median, or maximum pixel luminance. According to the prediction model, the discomfort luminance level of a head-mounted display was represented as a positive linear function in log₁₀ units using the previous adaptation luminance when luminance is calculated as maximum area luminance.     

体育馆LED显示屏的光色参数测量

该文主要通过体育场馆中LED显示屏的测量实例,介绍了广州亚运会网球场等体育场馆中LED显示屏的亮度、对比度、白场色品坐标、色温、亮度均匀度、基色主波长和视角等重要参数的检测方法方案,总结了体育场馆LED显示屏检测经验,并对相应标准提出了一些建议。     

3种颜色空间的亮度分量在伪装效果评价中的应用

结合伪装效果评价的要求,以中国颜色体系为基础,建立了CIE1976L*a*b*、LMS、ιαβ这3种颜色空间的64级亮度分量数据库,利用灰度直方图相似度算法,分析了以上3种亮度分量在伪装效果评价中的应用问题.实验结果表明,L*分量具有均匀性较好,Lm分量和ι分量分别在灰度较低和灰度较高时,其伪装效果的评价结果与人眼判读...     

基于ST-CSLBP的混合时空背景建模算法

针对背景建模方法对场景光照变化较为敏感,提出融合时间预测和空域纹理信息设计全新的时空-对称ST-CSLBP算子,构建基于ST-CSLBP直方图的混合时空背景模型,融合时域分布统计法和空域背景各自的优势,以同时适应长时光照以及短时的光照变化.实验表明,该算法与现有背景建模算法相比,具有较好的准确率和检索率.     

基于灰色理论的隧道照明多级亮度智能控制策略研究

在隧道照明控制系统中,维持隧道内外光线强度的平衡是控制的目的。因此根据外部照度控制灯光的开灯率是控制系统设计过程中的重要环节。在分析了光照度检测条件的前提下,提出了灰色理论的隧道照明多级亮度智能控制策略,解决了开灯率高,能源浪费的问题。