A novel driving method and device to reduce color breakup in color‐sequential displays

Abstract— Color‐sequential displays offer a better luminous efficiency, a higher spatial resolution, and a lower cost than conventional displays. However, a common problem is that visual effects cause color edge‐blurring of a moving picture, a phenomenon called color breakup or rainbow effects. Most driving methods, such as increasing the frame rate and inserting a black/white frame or another color sub‐frame to reduce the color breakup in color sequential displays has been presented in many papers, but every method has some limitations and problems. An innovative driving method and device to reduce the color‐breakup phenomenon will be demonstrated in this paper, designed without increasing the driving frequency. Instead, the brightness is increased by one third at the very least. Our method divides the driving frequency into four sub‐frames (WRGB), which is operated at 180 Hz compared to 240 Hz for conventional driving. Our result shows that the image quality is improved. The color‐breakup simulation based on “eye trace integration” and compensated white light will also be presented in this paper.     

Overview Paper: Intelligent color imaging*

Abstract— With the 600th anniversary of Johann Gutenberg's birth in 2000 A.D., we should look back at the historical significance of letterpress technology and take a step forward into the new age of color imaging. Currently, digital‐imaging technology plays a leading role in visual communications, but meets severe challenges to satisfy human vision. It is essential to consider what human vision “sees” in order to capture, store, transmit, and reproduce a truly realistic image just as human vision. Advances not only in high‐precision and high‐definition digital media but also in intelligent image‐processing technologies will be helpful in producing more aesthetic and pleasant imaging. This paper briefly introduces “intelligent” processing towards that goal by using region‐based spatially variant, and scene‐referred approaches.     

Optimization of operating parameters of video display units in text reading task: Luminance contrast,viewing distance,and character size

Abstract— The purpose of this study is to determine the reading performance of operators on a desktop computer. The effects of luminance contrast, viewing distance, and character size on the speed of reading were investigated. The luminance contrast between the background and character was varied while color contrast was held near‐constant. Stimuli with different levels of character size, viewing distance, and luminance contrast were considered while assessing the readability performance. The luminance contrast between the background and character (0.01, 0.15, and 1.00), character sizes (0.2, 1.5, and 4°), and viewing distance (40, 50, and 60 cm) were used, and the performance of the operators were recorded in terms of words per minutes (WPM). Standard workplace design recommendations to position the center of the visual display terminal (VDT) 15° and 40° below horizontal eye level were used for the visually intensive readability task. An orthogonal array, the signal‐to‐noise (S/N) ratio, and the analysis of variance (ANOVA) were employed to investigate the above‐mentioned operating parameters to determine the optimum readability performance. The results indicated that performance was better at a 15° viewing angle as compared to a 40° viewing angle.     

Contrast effect in evaluating the sense of presence for wide displays

Abstract— To evaluate the relationship between visual angle and the sense of presence for wide displays, two experiments were conducted in which the visual angle (ranging from 30 to 100°) was manipulated as a between‐ and within‐subjects factor, respectively. Two‐hundred subjects participated in both experiments. In the within‐subjects evaluation, presence scores increased as the visual angle widened, while those in the between‐subjects evaluation did not increase significantly for a wide visual angle. It can be concluded that “contrast effect,” i.e., a bias caused by comparing different visual angles, greatly affects the ratings of sense of presence.     

Stimulus duration thresholds for reading numerical time information: Effects of visual size and number of time units

We examined the effects of the visual size and the number of digits on reading numerical time information in young adults. Using an adaptive staircase procedure, minimal stimulus presentation duration (MSPD) for 80%-correct responses was determined for visual sizes ranging from 0.1° to 15°, when reading 1 (“mm”), 2 (“hh:mm”) or 3 (“hh:mm:ss”) 2-digit units of time information. All three time types revealed U-shaped relations between MSPD and visual size, with the characteristics of the relation depending on the number of time units. Time type had two different effects. First, longer time types gave rise to longer MSPDs, as more elements needed to be encoded into working memory. Second, longer time types gave rise to smaller ranges of optimal visual character size, decreasing from 0.2–2° for the 1-unit time type to 0.3–0.5° for the 3-unit time type. The lower boundary of the optimal range of visual size may be understood as resulting from acuity limitations. The shift in the upper boundary of the optimal range of visual size is suggested to reflect the change in size of the visual span associated with larger visual character sizes.     

Visualization of large networks with min-cut plots,A-plots and R-MAT

What does a “normal” computer (or social) network look like? How can we spot “abnormal” sub-networks in the Internet, or web graph? The answer to such questions is vital for outlier detection (terrorist networks, or illegal money-laundering rings), forecasting, and simulations (“how will a computer virus spread?”).The heart of the problem is finding the properties of real graphs that seem to persist over multiple disciplines. We list such patterns and “laws”, including the “min-cut plots” discovered by us. This is the first part of our NetMine package: given any large graph, it provides visual feedback about these patterns; any significant deviations from the expected patterns can thus be immediately flagged by the user as abnormalities in the graph. The second part of NetMine is the A-plots tool for visualizing the adjacency matrix of the graph in innovative new ways, again to find outliers. Third, NetMine contains the R-MAT (Recursive MATrix) graph generator, which can successfully model many of the patterns found in real-world graphs and quickly generate realistic graphs, capturing the essence of each graph in only a few parameters. We present results on multiple, large real graphs, where we show the effectiveness of our approach.     

Identifying semantic blocks in Web pages using Gestalt laws of grouping

Semantic block identification is an approach to retrieve information from Web pages and applications. As Website design evolves, however, traditional methodologies cannot perform well any more. This paper proposes a new model to merge Web page content into semantic blocks by simulating human perception. A “layer tree” is constructed to remove hierarchical inconsistencies between the DOM tree representation and the visual layout of the Web page. Subsequently, the Gestalt laws of grouping are interpreted as the rules for semantic block detection. During interpretation, the normalized Hausdorff distance, the CIE-Lab color difference, the normalized compression distance, and the series of visual information are proposed to operationalize these Gestalt laws. Finally, a classifier is trained to combine each operationalized law into a unified rule for identifying semantic blocks from the Web page. Experiments are conducted to compare the efficiency of the model to a state-of-art algorithm, the VIPS. The comparison results of the first experiment show that the GLM model generates more “true positives” and less “false negatives” than VIPS. The next experiment upon a large-scale test set produces an average precision of 90.53 % and recall rate of 90.85 %, which is approximately 25 % better than that of VIPS.     

基于自适应滤波和MBVC的矢量误差扩散法

针对彩色图像最小亮度分布处理方法中存在的由于使用固定误差扩散系数带来的方向性纹理缺陷问题,提出了一种基于自适应滤波的最小亮度分布处理改进算法。该算法通过自适应的方法,在处理过程中随图像特性动态调节扩散系数,使得处理结果更加逼近原始图像。使用最小亮度分布的办法,减小因各颜色之间亮度不同所带来的彩色噪声。实验结果表明,该算法处理输出图像更加柔和,在图像渐变区域没有明显纹理,效果更好。     

A Generalized Cubemap for Encoding 360° VR Videos using Polynomial Approximation

360^° VR videos provide users with an immersive visual experience. To encode 360^° VR videos, spherical pixels must be mapped onto a two‐dimensional domain to take advantage of the existing video encoding and storage standards. In VR industry, standard cubemap projection is the most widely used projection method for encoding 360^° VR videos. However, it exhibits pixel density variation at different regions due to projection distortion. We present a generalized algorithm to improve the efficiency of cubemap projection using polynomial approximation. In our algorithm, standard cubemap projection can be regarded as a special form with 1st‐order polynomial. Our experiments show that the generalized cubemap projection can significantly reduce the projection distortion using higher order polynomials. As a result, pixel distribution can be well balanced in the resulting 360^° VR videos. We use PSNR, S‐PSNR and CPP‐PSNR to evaluate the visual quality and the experimental results demonstrate promising performance improvement against standard cubemap projection and Google's equi‐angular cubemap.     

Sparsely Precomputing The Light Transport Matrix for Real‐Time Rendering

Precomputation‐based methods have enabled real‐time rendering with natural illumination, all‐frequency shadows, and global illumination. However, a major bottleneck is the precomputation time, that can take hours to days. While the final real‐time data structures are typically heavily compressed with clustered principal component analysis and/or wavelets, a full light transport matrix still needs to be precomputed for a synthetic scene, often by exhaustive sampling and raytracing. This is expensive and makes rapid prototyping of new scenes prohibitive. In this paper, we show that the precomputation can be made much more efficient by adaptive and sparse sampling of light transport. We first select a small subset of “dense vertices”, where we sample the angular dimensions more completely (but still adaptively). The remaining “sparse vertices” require only a few angular samples, isolating features of the light transport. They can then be interpolated from nearby dense vertices using locally low rank approximations. We demonstrate sparse sampling and precomputation 5 × faster than previous methods.     

Target point‐based path‐following controller for a car‐type vehicle using bounded controls

In this paper, we have studied the control problem of target point‐based path following for car‐type vehicles. This special path‐following task arises from the needs of vision‐based guidance systems, where a given target point located ahead of the vehicle, in the visual range of the camera, must follow a specified path. A solution to this problem is developed through a nonlinear transformation of the path‐following problem into a reference trajectory tracking problem, by modeling the target point as a virtual vehicle. The use of target point complicates the control problem, as the development produces a first‐order nonlinear nonglobally Lipschitz differential equation with finite escape time. This problem is solved by using small control signals. Bounded feedback laws are designed to control the real vehicle's angular acceleration and the virtual vehicle's velocity, to achieve stability. The resulting controller is globally asymptotically stable with respect to the origin, the proof of which is derived from Lyapunov‐based arguments and a bootstrap argument. It is also shown that the use of exponentially convergent observers/differentiators does not affect the stability of the closed‐loop system. The effectiveness of this controller has been illustrated through simulations. Copyright © 2014 John Wiley & Sons, Ltd.     

Radiation physics and modelling for off-nadir satellite-sensing of non-Lambertian surfaces

The primary objective of this paper is to provide a deeper understanding of the physics of satellite remote-sensing when off-nadir observations are considered. Emphasis is placed on the analysis and modelling of atmospheric effects and the radiative transfer of non-Lambertian surface reflectance characteristics from ground-level to satellite locations. We evaluate the relative importance of spectral, spatial, angular, and temporal reflectance characteristics for satellite-sensed identification of vegetation types in the visible and near-infrared wavelength regions. Highest identification value is attributed to angular reflectance signatures. Using radiative transfer calculations to evaluate the atmospheric effects on angular reflectance distributions of vegetation surfaces, we identify atmosphere-invariant angular reflectance features such as the “hot spot” and the “persistent valley”. A new atmospheric correction formalism for complete angular reflectance distributions is described. A sample calculation demonstrates that a highly non-Lambertian measured surface reflectance distribution can be retrieved from simulated satellite data in the visible and near infrared to within about 20% accuracy for almost all view directions up to 60° off-nadir. Thus the high value of angular surface reflectance characteristics (the “angular signature”) for satellite-sensed feature identification is confirmed, which provides a scientific basis for future off-nadir satellite observations.     

Designating “hot” items in multiple‐choice questions—A strategy for reviewing course materials

Suppose learners use their free time to go online to review course materials, and they do so by taking optional tests that consist of multiple‐choice questions (MCQs). What will happen if, for every practice question, there is always a choice (out of four possible choices) that is marked as “the (current) hot choice?” Will this make any difference in learning effects? To answer this question, an educational experiment was conducted. It was found that “hot designations” helped the experimental group perform significantly better in both the immediate post‐test exam and a delayed post‐test exam and that learners with higher levels of initial knowledge benefited more from this review strategy. From the results of a follow‐up questionnaire and one‐on‐one interviews, it was found that the proposed review strategy promoted a more thorough thinking style in subjects of the experimental group.     

Image‐inspired haptic interaction

We add new modality to image‐based visualization by converting ordinary photos into tangible images, which can be then haptically rendered. This is performed by interactive sketching haptic models on the photos so that the models match the image parts, which will become tangible. In contrast to common geometric modelling, we define the haptic models in a three‐dimensional haptic modelling space distorted by the central projection. Analytic FRep functions (variants of implicit functions) are mostly used for defining the haptic models. The tangible images thus created can realistically simulate some actual three‐dimensional scenes by implementing the principle “What You See Is What You Touch” while in fact still be 2D images. Copyright © 2015 John Wiley & Sons, Ltd.     

Remarks concerning the optimization of matrix codes

This paper describes the results of a general theory of matrix codes correcting a set of given types of multiple errors. A detailed study has been made of certain matrix classes of these systematic binary error correcting codes that will correct typical errors of some digital channels. These codes published by Elias,^(2,3) Hobb's,⁽⁵⁾ and Voukalis⁽¹¹⁾ account for this theory and other new families of binary systematic matrix codes of arbitrary size, correcting random, burst and clusters of errors are given here. Also presented here are the basic ideas of each of these codes. We can easily find practical decoding algorithms for each of these codes. The characteristic calculation of the parity check equations that the information matrix codebook has to satisfy are also shown. Further on we deal with the optimum construction of these codes showing their use in certain applications. We answer questions such as: “What is the optimum size of the code?” “What is the best structure of the code?” “What is the probability of error correction and the mean error correction performance?” Consequently, in this paper we also describe the results of an extensive search for optimum matrix codes designed to correct a given set of multiple errors as well as their implementation.     

Circumnavigation of a speedy unpredictable target by a group of speed‐ and acceleration‐limited robots

An unpredictably maneuvering speedy target travels in a plane, which also hosts a team of fully actuated robots whose velocities and accelerations are upper‐bounded in magnitude. The robots should approach the target and then follow it at a prespecified distance. They also should achieve an even self‐distribution around the target and a given angular velocity of rotation about the target. Every robot has access to the relative position of the target and other robots (in the latter case, within a finite “visibility” range) and to the angular speed of its own pure rotation; access to the coordinates of its own linear velocity in its own local frame is also employed in some cases. The robots are not equipped with communication facilities and cannot distinguish among one another; assignment of different roles to various robots is infeasible. Necessary conditions for the mission feasibility are first obtained. A distributed control law is then presented, and its global convergence and collision avoidance property are rigorously justified under slight enhancement of the just mentioned necessary conditions. The performance of the control law is illustrated by computer simulations.     

Multimodal feature-wise co-attention method for visual question answering

VQA attracts lots of researchers in recent years. It could be potentially applied to the remote consultation of COVID-19. Attention mechanisms provide an effective way of utilizing visual and question information selectively in visual question and answering (VQA). The attention methods of existing VQA models generally focus on spatial dimension. In other words, the attention is modeled as spatial probabilities that re-weights the image region or word token features. However, feature-wise attention cannot be ignored, as image and question representations are organized in both spatial and feature-wise modes. Taking the question “What is the color of the woman’s hair” for example, identifying the hair color attribute feature is as important as focusing on the hair region. In this paper, we propose a novel neural network module named “multimodal feature-wise attention module” (MulFA) to model the feature-wise attention. Extensive experiments show that MulFA is capable of filtering representations for feature refinement and leads to improved performance. By introducing MulFA modules, we construct an effective union feature-wise and spatial co-attention network (UFSCAN) model for VQA. Our evaluation on two large-scale VQA datasets, VQA 1.0 and VQA 2.0, shows that UFSCAN achieves performance competitive with state-of-the-art models.     

Self-alignment observation and conductivity evaluation in micro chips integration with square binding pattern

A “square” binding alignment pattern, with relatively higher energy barrier but four fully aligned orientations at four off-set angles of 0°, 90°, 180°, and 270°, has been analyzed by introducing a concept of the overlap ratio, compared to a “rectangular” one. Both the “square-pattern” micro-chips and the substrate with the “square-pattern” binding sites were fabricated using one-mask micromachining process, and the self-alignment in situ observation under three different off-set orientation angles of 35°, 46°, and 90° was demonstrated using a high-speed video camera. Sequential images reveal a slow translational motion in the early stage followed by a faster rotational alignment. A novel technique has been further proposed for the conductivity evaluation by using three kinds of SAM films, i.e., C12, C18, and Terphenyl. The preliminary measurements indicate that, using the proposed novel structure, the Terphenyl film is believed to be desirable as a conductive SAM film for self-alignment of micro-chips.     

The present and future of electronic paper

Abstract— With the rise of electrophoretic‐display media from several sources, the world is opening up for new uses of electronic displays. Where “immersive reading” used to be a task strictly reserved for paper, displays can now fulfill that role. Many challenges still remain, such as full‐color photograph‐like performance and video speeds. However, in view of recent accomplishments showing near‐video‐speed switching and potential for full color, after electrophoretic displays obtain a slice of the reading market, application of these developments will take us a significant step towards full‐color animated paper‐like displays. The developments that have led to the presence of electronic paper in the market today will be described, and developments that are about to happen will be discussed.     

User‐Controllable Color Transfer

This paper presents an image editing framework where users use reference images to indicate desired color edits. In our approach, users specify pairs of strokes to indicate corresponding regions in both the original and the reference image that should have the same color “style”. Within each stroke pair, a nonlinear constrained parametric transfer model is used to transfer the reference colors to the original. We estimate the model parameters by matching color distributions, under constraints that ensure no visual artifacts are present in the transfer result. To perform transfer on the whole image, we employ optimization methods to propagate the model parameters defined at each stroke location to spatially‐close regions of similar appearance. This stroke‐based formulation requires minimal user effort while retaining the high degree of user control necessary to allow artistic interpretations. We demonstrate our approach by performing color transfer on a number of image pairs varying in content and style, and show that our algorithm outperforms state‐of‐the‐art color transfer methods on both user‐controllability and visual qualities of the transfer results.