Measurement of minimum angle of resolution (MAR) for the spatial grating consisting of lines of two colors

Minimum angle of resolution (MAR) was measured for the grating which consisted of lines of two colors selected from Red, Green, Blue, White and Black. Method of two alternative forced choice (2AFC) was used where the participants were asked to answer the direction of the color grating of the horizontal or vertical directions. From the measured psychometric function of the ratio of the correct answers, MAR which corresponded to the threshold of 75% correct answer ratio was determined. MAR of the grating patches with more than one primary color was measured to be affected by the combination of colors and to be 10–30% larger than that of the grating patch of White–Black. While the resolving power for Blue pattern had been known to be worse than those for Green and Red patterns, MAR of the grating including Blue was not always the worst.     

Measurement of binocular disparity in polarized based stereoscopic display by using digital camera

This work presents an image displacement measurement by using a box pattern and the edge spread function analysis in the polarized based stereoscopic displays. The measurement determines to identify three factors (i.e., box size, image displacement, and spatial frequency response (SFR)) from the box patterns. The polarized based stereoscopic displays might sacrifice pixels for producing 3D images, which might produce errors in the image displacement and then affect the depth perception indirectly. Based on the measurement, the errors can be quantified by using the three factors. Owing to the light leakage distorting the edge spread function to obtain an inferior SFR, exactly how light leakage affects the edge spread function can be resolved on the basis of the SFR results, especially at a frequency (1/display pixel) of 1.9 in the case of the horizontal displacement. Light leakage also induces the error of the box height in even and odd intervals of the vertical displacements more than 2 pixels and 0.5 pixels, respectively. The image displacement measurement provides a simple and comprehensive means of evaluating the optical characteristics, disparity, and sharpness of the stereoscopic displays, via the three factors.     

PC display resolution matched to the limits of visual acuity

Abstract— This experiment determined the maximum useful resolution for a desktop PC display. We assumed that in the absence of limitations attributable to the display, the eye's spatial resolution determined the minimum‐size letters that could be recognized. We then introduced a spatial‐resolution limit representing the display and increased the size applied to 16 upper‐case letters until observers again had difficulty recognizing the letters. The eye and display affected text recognition equally when the size of the just‐recognizable letters had to be 1.5× larger than when the display's effect was absent. An analysis of our results indicated that eye's visual acuity and display resolution are of approximate equivalence when a 186‐dpi display is viewed at a distance of 46 cm (18 in). Comparable results were observed for three additional stimulus types: text‐like nonsense symbols, gray‐scale PC computer icons, and the same computer icons with colored features.     

Measurement of the lens accommodation in viewing stereoscopic displays

In observing the stereoscopic display at the viewing distance of 1 m, the amount of the perceived depth was determined by the positions of the crossing point that the viewing direction of two eyes intersect. The positions of the crossing points of stereoscopic stimuli were controlled, and the accommodation was measured by the autorefractometer for the seven participants. Accommodation was also measured when viewing the real film chart which was placed at the same position as these crossing points. The accommodation change when viewing the stereoscopic display was measured to be noticeable only when the crossing point was quite near the participant, but this change was still much smaller compared with the accommodation change when viewing the real film chart. This change in accommodation implies the possible occurrence of fatigue related to the accommodation–convergence conflict, while the constant accommodation within the range of DOF implies no conflict between the accommodation and convergence. This measurement scheme may be used to define the range of DOF where the accommodation remains little changed, and thus define the depth of the 3D object at which no accommodation–convergence conflict occurs, for a given stereoscopic display.     

Effect of 3D depth on the resolution and the observed image for auto‐stereoscopic multi‐view 3D display

In auto‐stereoscopic multi‐views, blurring occurs due to the incomplete separation of views for non‐zero depths. How this blur affects a 3D image was investigated using the commercial multi‐view 3D. The 3D input signal consisted of the square pattern and the gratings of various width and gray level values of G1 and G2. The various combinations of G1 and G2 were used to investigate the dependence of blur on gray G1 and G2 values. The 3D depth caused blurring, which caused a decrease in contrast modulation. Hence, the 3D resolution determined from contrast modulation was affected by the depth and became worse with increasing depth. Therefore, 3D resolution may be used to define the depth range within which the image degradation due to blurring is acceptable. Blur edge width values at the boundaries of gray G1 and G2 were measured and found to be similar irrespective of G1 and G2 values at the same depth. This was because blur was caused by the incomplete separation of views that are independent of G1 and G2. Hence, the blurriness of the observed 3D image is determined only by the depth. The 3D resolution and blur edge width might be useful to characterize the performance of auto‐stereoscopic multi‐view 3D.     

基于感知视觉重要性的立体图像质量评价

视觉心理、生理因素是有效、准确评价图像质量的重要依据.尽管在计算层面已有众多视觉心理、生理计算模型及方法为其提供支持,但在图像质量评价任务中如何分析各种孤立方法之间的内在关系进而使之有效协同,是使得评价结果更符合人主观评测的关键.从图像质量评价的角度出发,功能上将人眼的视觉注意区域定义并数学形式化为视觉初期注意区域与视觉转移期的劣质区域;同时考虑人眼的感知冗余特性,结合JND感知冗余模型,进而提出了图像质量评价范畴下的视觉感知模型PVSSIM.以此为依据,将感知视觉的方法在二维图像数据库中验证其可行性,并将其引入到立体图像质量评价中.实验结果表明,提出的客观评价方法与传统方法相比,充分考虑到了图像质量评价任务中各种视觉心理、生理因素的协同,与人主观的图像质量评价相比具有更高的相关度,评价方法在立体图像库中能很好地与主观评价相吻合,达到了预期的效果.     

Cross‐talk acceptability in natural still images for different (auto)stereoscopic display technologies

Abstract— One of the most annoying distortions in (auto)stereoscopic displays is probably cross‐talk, visible as double edges, which is mainly caused by an imperfect separation of left‐ and right‐eye images. For different types of three‐dimensional (3‐D) displays, cross‐talk is caused by different origins, which could result in different levels of perceived image distortion. To evaluate the influence of (auto)stereoscopic display technology on cross‐talk perception, optical measurements and subjective assessments were performed with three different types of 3‐D displays. It is shown with natural still images that the 3‐D display technology with the lowest luminance and contrast level tolerates the highest level of cross‐talk, while still maintaining an acceptable image‐quality level.     

Minimum required angular resolution of smartphone displays for the human visual system

There has been a rapid increase in the resolution of small‐sized and medium‐sized displays. This study determines an upper discernible limit for display resolution. A range of resolutions varying from 254–1016 PPI were evaluated using simulated display by 49 subjects at 300 mm viewing distance. The results of the study conclusively show that users can discriminate between 339 and 508 PPI and in many cases between 508 and 1016 PPI.     

Angular dependence of the performance of stereoscopic liquid‐crystal‐display (LCD) television using shutter glasses (SG)

Abstract— 3‐D cross‐talk typically represents the ratio of image overlap between the left and right views. For stereoscopic LCDs using shutter‐glasses technology, 3‐D cross‐talk for stereoscopic LCD TV with a diagonal size of 46 in. and vertical alignment (VA) mode was measured to change from 1% to 10% when the stereoscopic display is rotated around the vertical axis. Input signals consist of the left and right images that include patterns of different amounts of binocular disparity and various gray levels. Ghost‐like artifacts are observed. Furthermore, intensities of these artifacts are observed to change as the stereoscopic display is rotated about the vertical axis. The temporal luminance of the LCD used in stereoscopic TV was found to be dependent on the viewing direction and can be considered as one cause of the phenomenon of angular dependence of performance for stereoscopic displays.     

Revisit and compare Ma equivalence and Zhang equivalence of minimum velocity norm (MVN) type

In this paper, by revisiting Ma et al.’s inspiring work (specifically, Ma equivalence, ME) and Zhang et al.’s inspiring work (specifically, Zhang equivalence, ZE), which both investigate the equivalence relationships of redundancy-resolution schemes at two different levels, but with different formulations, the general scheme formulations and equivalence analyses of ME and ZE are presented. Besides, being a case study, the ME and ZE of minimum velocity norm (MVN) type are investigated for the inverse-kinematics (IK) problem solving. Moreover, the link and difference between the MVN-type ME and ZE are analyzed, summarized and presented methodologically, systematically, and computationally in this paper. In order to numerically compare the ME and ZE of MVN type, a Rhodonea-path tracking task based on PUMA560 robot manipulator is tested and fulfilled by employing the original velocity-level MVN schemes and its equivalent acceleration-level MVN schemes of ME and ZE. The simulative and numerical results not only verify the effectiveness of the velocity-level and acceleration-level schemes of MVN-type ME and ZE, but also validate the reasonableness of such two proved equivalence relationships. More importantly, these results show quantitatively and comparatively the respective advantages and future applications of MVN-type ME and ZE for the IK problem solving.     

无线传感器网络最小能量簇群构造策略

尽可能延长无线传感器网络（WSNs）的生命周期是设计和部署网络所面临的最大挑战之一。由于节点配备的能量有限，采用分簇方式组织节点可以极大地降低节点与Sink节点通信的能耗。簇群成员节点和簇头的通信方式与簇群的拓扑结构决定整个簇群的能量消耗速度。文中分析了簇群节点采用Multi-hop通信方式时，节点通过中继节点与簇头通信时能量消耗的模型，然后在选择链路的最优跳数的基础上，提出建立最小能量中继链路的方法，实现通信能耗的最小化。对WSNs的设计和实施具有一定的指导意义。     

考虑泥沙水下休止角的淤积量测报模型及优化

提高水库泥沙淤积量的测报精度对水库的运行与管理有着重要意义。通过分析论证由水下地形点构建的TIN三角网的边、三角形面及泥沙水下休止角之间的几何关系,提出了优化测报模型的休止角条件;进而利用Matlab编制优化的测报程序;最后结合灞河橡胶坝库区的淤积数据进行了验证。结果表明：基于泥沙水下休止角的淤积量测报模型可以剔除带有粗差的地形点数据,提高了淤积量的测报精度。     

Measurement of the mechanical properties of brightness enhancement films (BEFs) for LCDs by optical interferometry

The brightness enhancement film (BEF) is one of the important components in the liquid crystal displays (LCDs). Since the thicknesses of BEFs are very less, it increases the difficulty to measure their mechanical properties. In this paper, we successfully propose a methodology by combining the micro tensile test and optical interferometry to characterize Young’s moduli and Poisson’s ratios of BEFs. In addition, the thermal and hygrothermal effects on the mechanical properties of BEFs were also investigated. The finite element analysis (FEA) was utilized to verify the precision of our proposed methodology. The results show that Young’s moduli of BEFs are influenced by temperature and humidity whereas Poisson’s ratios of BEFs are less influenced by temperature and humidity.     

Multi-temporal monitoring of wetland water levels in the Florida Everglades using interferometric synthetic aperture radar (InSAR)

Interferometric synthetic aperture radar (InSAR) techniques can successfully detect phase variations related to the water level changes in wetlands and produce spatially detailed high-resolution maps of water level changes. Despite the vast details, the usefulness of the wetland InSAR observations is rather limited, because hydrologists and water resources managers need information on absolute water level values and not on relative water level changes. We present an InSAR technique called Small Temporal Baseline Subset (STBAS) for monitoring absolute water level time series using radar interferograms acquired successively over wetlands. The method uses stage (water level) observation for calibrating the relative InSAR observations and tying them to the stage's vertical datum. We tested the STBAS technique with two-year long Radarsat-1 data acquired during 2006-2008 over the Water Conservation Area 1 (WCA1) in the Everglades wetlands, south Florida (USA). The InSAR-derived water level data were calibrated using 13 stage stations located in the study area to generate 28 successive high spatial resolution maps (50 m pixel resolution) of absolute water levels. We evaluate the quality of the STBAS technique using a root mean square error (RMSE) criterion of the difference between InSAR observations and stage measurements. The average RMSE is 6.6 cm, which provides an uncertainty estimation of the STBAS technique to monitor absolute water levels. About half of the uncertainties are attributed to the accuracy of the InSAR technique to detect relative water levels. The other half reflects uncertainties derived from tying the relative levels to the stage stations' datum.     

基于视觉注意的医学图像感兴趣区域提取*

提出一种基于视觉注意机制的医学图像感兴趣区域提取方法。受生物学启发,该方法模仿人类自下而上的视觉选择性注意过程,通过计算图像中每个像素的全局对比度,构造相应的显著图,并根据显著图,检测出图像中的显著区域。利用多幅医学图像对本方法进行评估,结果表明,该方法能够快速、精确地提取图像中的感兴趣区域,在提取结果和运算速度上均取得了令人满意的效果。     

Implementation path and reference framework for Industrial Internet Platform (IIP) in product service system using industrial practice investigation method

With the development of intelligent sensing, edge computing, fog computing, cloud computing, parallel computing, smart grid, big data, block chain, 5G, cyber-physical systems, digital twins, machine learning and other technologies, the industrial internet has undergone control network stage, sensor network stage, internet stage, Internet of Things (IoT) stage, Industrial Internet of Things (IIoT) stage, and Industrial Internet (II) stage, etc. In the existing research, scholars focus on a local dot, such as: technology, function, elements and application based on industrial internet. However, there is a lack of an overall framework to study the top-level planning of Industrial Internet Platform (IIP) from a systematic perspective. On the other hand, there are few studies on the detailed path and steps for implementing IIP in a specific enterprise in a specific industry. The objective of this paper is to study a reference framework and industrial implementation path for IIP in product service system using industrial practice investigation method, which meets the needs of industry on the basis of existing theory and industrial practice, and to provide reference for government and industry planning, design, implementation and promotion of IIP. In addition, the proposed reference framework and industrial implementation for IIP in product service system can enhance the core value of the enterprise and increase benefits.     

Asymptotic efficiency of kernel support vector machines (SVM)

The paper analyzes the asymptotic properties of Vapnik’s SVM-estimates of a regression function as the size of the training sample tends to infinity. The estimation problem is considered as infinite-dimensional minimization of a regularized empirical risk functional in a reproducing kernel Hilbert space. The rate of convergence of the risk functional on SVM-estimates to its minimum value is established. The sufficient conditions for the uniform convergence of SVM-estimates to a true regression function with unit probability are given. Translated from Kibernetika i Sistemnyi Analiz, No. 4, pp. 81–97, July–August 2009     

认知物联网频谱感知数据伪造攻击研究

认知物联网可以看作是＂认知无线电传感器节点的分布式网络＂,它通过在物联网中实现认知无线电技术,可以有效地解决物联网面临的频谱资源紧张等问题。文章提出了认知物联网的基本定义和体系结构,设计了频谱感知数据伪造（SSDF）攻击模型,分析了基于数据融合、基于一致性、基于SVDD算法、基于异常值检测等四种解决方案的原理与性能。     

虚拟环境建模中层次细节(LOD)的优化

基于层次结构的动态简化方法，根据视点的变化，提出了优化的求精算法，能够实时连续的转换LOD模型，从而提高虚拟环境中实时仿真的效果，辅助介绍了层次细节技术适用范围。同时对不同简化算法作了比较，给出了一个比较直观的明细表。     

Improvement of the accuracy in boundary element method based on high-order discretization

The boundary element method (BEM) is a popular method to solve various problems in engineering and physics and has been used widely in the last two decades. In high-order discretization the boundary elements are interpolated with some polynomial functions. These polynomials are employed to provide higher degrees of continuity for the geometry of boundary elements, and also they are used as interpolation functions for the variables located on the boundary elements. The main aim of this paper is to improve the accuracy of the high-order discretization in the two-dimensional BEM. In the high-order discretization, both the geometry and the variables of the boundary elements are interpolated with the polynomial function P_m, where m denotes the degree of the polynomial. In the current paper we will prove that if the geometry of the boundary elements is interpolated with the polynomial function P_m+1 instead of P_m, the accuracy of the results increases significantly. The analytical results presented in this work show that employing the new approach, the order of convergence increases from O(L₀)^m to O(L₀)^m+1 without using more CPU time where L₀ is the length of the longest boundary element. The theoretical results are also confirmed by some numerical experiments.