Sketchy rendering for information visualization

We present and evaluate a framework for constructing sketchy style information visualizations that mimic data graphics drawn by hand. We provide an alternative renderer for the Processing graphics environment that redefines core drawing primitives including line, polygon and ellipse rendering. These primitives allow higher-level graphical features such as bar charts, line charts, treemaps and node-link diagrams to be drawn in a sketchy style with a specified degree of sketchiness. The framework is designed to be easily integrated into existing visualization implementations with minimal programming modification or design effort. We show examples of use for statistical graphics, conveying spatial imprecision and for enhancing aesthetic and narrative qualities of visual- ization. We evaluate user perception of sketchiness of areal features through a series of stimulus-response tests in order to assess users’ ability to place sketchiness on a ratio scale, and to estimate area. Results suggest relative area judgment is compromised by sketchy rendering and that its influence is dependent on the shape being rendered. They show that degree of sketchiness may be judged on an ordinal scale but that its judgement varies strongly between individuals. We evaluate higher-level impacts of sketchiness through user testing of scenarios that encourage user engagement with data visualization and willingness to critique visualization de- sign. Results suggest that where a visualization is clearly sketchy, engagement may be increased and that attitudes to participating in visualization annotation are more positive. The results of our work have implications for effective information visualization design that go beyond the traditional role of sketching as a tool for prototyping or its use for an indication of general uncertainty

Depth-aware neural style transfer

Neural style transfer has recently received significant attention and demonstrated amazing results. An efficient solution proposed by Johnson et al. trains feed-forward convolutional neural networks by defining and optimizing perceptual loss functions. Such methods are typically based on high-level features extracted from pre-trained neural networks, where the loss functions contain two components: style loss and content loss. However, such pre-trained networks are originally designed for object recognition, and hence the high-level features often focus on the primary target and neglect other details. As a result, when input images contain multiple objects potentially at different depths, the resulting images are often unsatisfactory because image layout is destroyed and the boundary between the foreground and background as well as different objects becomes obscured. We observe that the depth map effectively reflects the spatial distribution in an image and preserving the depth map of the content image after stylization helps produce an image that preserves its semantic content. In this paper, we introduce a novel approach for neural style transfer that integrates depth preservation as additional loss, preserving overall image layout while performing style transfer

Proactive Evaluation of Traffic Signs Using a Traffic Sign Simulator

Traffic signs and pavement markings are a crucial aspect of road design since they are essential sources of information for road users to calibrate their driving behavior, evaluate route possibilities and cope with unexpected events. A proactive evaluation of (the quality of) these road design elements will help to improve the safety performance of the roadway. This paper presents the Traffic Sign Simulator, an innovative research tool to study the influence of these elements on road users’ routing decisions, lane choice and visual behavior, to investigate road users’ comprehension of these signs, and to collect suggestions for improvements. Using a driving simulator mock-up, participants navigate through a full HD video from route(s) in which the planned traffic signs have been digitally implemented using specialized software for camera-tracking and 3D video-integration. Participants’ route and lane choice and their visual behavior (using eye tracking) are monitored while driving through the scenario(s). Laptop preand post-tests are applied to collect additional in-depth information concerning the participants’ processing, comprehension and general evaluation of the traffic signs and suggestions for improvement. The paper illustrates the possibilities of the Traffic Sign Simulator with a case study that examined the effectiveness of temporary work zone signalization (i.e., traffic signs, digital information panels and pavement markings) as it was used during the reconstruction works on the Vilvoorde fly-over near Brussels, one of the busiest interchanges in the Belgian motorway network

A Bounded Measure for Estimating the Benefit of Visualization: Case Studies and Empirical Evaluation

Many visual representations, such as volume-rendered images and metro maps, feature a noticeable amount of information loss. At a glance, there seem to be numerous opportunities for viewers to misinterpret the data being visualized, hence undermining the benefits of these visual representations. In practice, there is little doubt that these visual representations are useful. The recently-proposed information-theoretic measure for analyzing the cost-benefit ratio of visualization processes can explain such usefulness experienced in practice, and postulate that the viewers' knowledge can reduce the potential distortion (e.g., misinterpretation) due to information loss. This suggests that viewers' knowledge can be estimated by comparing the potential distortion without any knowledge and the actual distortion with some knowledge. In this paper, we describe several case studies for collecting instances that can (i) support the evaluation of several candidate measures for estimating the potential distortion distortion in visualization, and (ii) demonstrate their applicability in practical scenarios. Because the theoretical discourse on choosing an appropriate bounded measure for estimating the potential distortion is yet conclusive, it is the real world data about visualization further informs the selection of a bounded measure, providing practical evidence to aid a theoretical conclusion. Meanwhile, once we can measure the potential distortion in a bounded manner, we can interpret the numerical values characterizing the benefit of visualization more intuitively.Comment: Following the SciVis 2020 reviewers' request for more explanation and clarification, the origianl article, "A Bounded Measure for Estimating the Benefit of Visualization, arxiv:2002.05282", has been split into two articles, on "Theoretical Discourse and Conceptual Evaluation" and "Case Studies and Empirical Evaluation" respectively. This is the second articl

Visual Perception and Cognition in Image-Guided Intervention

Surgical image visualization and interaction systems can dramatically affect the efficacy and efficiency of surgical training, planning, and interventions. This is even more profound in the case of minimally-invasive surgery where restricted access to the operative field in conjunction with limited field of view necessitate a visualization medium to provide patient-specific information at any given moment. Unfortunately, little research has been devoted to studying human factors associated with medical image displays and the need for a robust, intuitive visualization and interaction interfaces has remained largely unfulfilled to this day. Failure to engineer efficient medical solutions and design intuitive visualization interfaces is argued to be one of the major barriers to the meaningful transfer of innovative technology to the operating room. This thesis was, therefore, motivated by the need to study various cognitive and perceptual aspects of human factors in surgical image visualization systems, to increase the efficiency and effectiveness of medical interfaces, and ultimately to improve patient outcomes. To this end, we chose four different minimally-invasive interventions in the realm of surgical training, planning, training for planning, and navigation: The first chapter involves the use of stereoendoscopes to reduce morbidity in endoscopic third ventriculostomy. The results of this study suggest that, compared with conventional endoscopes, the detection of the basilar artery on the surface of the third ventricle can be facilitated with the use of stereoendoscopes, increasing the safety of targeting in third ventriculostomy procedures. In the second chapter, a contour enhancement technique is described to improve preoperative planning of arteriovenous malformation interventions. The proposed method, particularly when combined with stereopsis, is shown to increase the speed and accuracy of understanding the spatial relationship between vascular structures. In the third chapter, an augmented-reality system is proposed to facilitate the training of planning brain tumour resection. The results of our user study indicate that the proposed system improves subjects\u27 performance, particularly novices\u27, in formulating the optimal point of entry and surgical path independent of the sensorimotor tasks performed. In the last chapter, the role of fully-immersive simulation environments on the surgeons\u27 non-technical skills to perform vertebroplasty procedure is investigated. Our results suggest that while training surgeons may increase their technical skills, the introduction of crisis scenarios significantly disturbs the performance, emphasizing the need of realistic simulation environments as part of training curriculum

3DCGアニメーション技術を利用したインドネシアの伝統的な演劇芸術の保存

There are various types of traditional theater art called Wayang in Indonesia. One of them is Wayang Beber of Pacitan, which originated in the 17th century and has a long history of over 400 years. Despite the precious value of these art works as cultural, historical, and religious heritage of Indonesia, their preservation is currently in a critical condition. Because of the humid climate of Indonesia it is hard to keep pictures in a good condition, and in addition, the country is experiencing a dramatic decrease in the number of artists to draw them, lack of budget for preservation, and lack of overall national interest in the preservation of Wayang Beber of Pacitan. It is feared that without a quick action, Wayang Beber of Pacitan could be lost in the near future. The purpose of this research is to preserve the Wayang Beber of Pacitan in a reasonable manner, so that Indonesian cultural heritage survives eternally. In order to solve the problems, the author proposes an application of 3-Dimensional Computer Graphics (3DCG) technology as a tool to reproduce and save the art digitally. The author then develops a 3DCG system specifically to generate Wayang Beber of Pacitan art works. As an example, some digital art reproduction works of Wayang Beber of Pacitan are generated using the proposed system. This thesis consists of 6 chapters: Chapter 1 describes background, scope, and objectives of the research. This chapter also provides literature survey related to digital preservation of cultural heritage, and specific nonphotorealistic CG techniques such as silhouette rendering, pattern generation. Chapter 2 discusses the research to compile archives of Wayang Beber of Pacitan. This research is performed by surveying related research works, observing the actual artwork and gathering data from interviews. The results of this survey are used as a basis for analyzing the visual style of Wayang Beber. After the identification of characteristics of the visual style, details of the required method for converting the pictures into 3DCG animation are determined. The original Wayang Beber is composed of many parts. It is difficult to create parts one by one in 3DCG, therefore a method that can generate the picture semi-automatically is considered to be used. Chapter 3 discusses the development of an outline shader. This shader is used to simulate outlines of Wayang Beber pictures on a 3DCG model. Outlines of Wayang Beber have some typical characteristics, such as expressive brushstrokes and variations in thicknesses. To produce an outline with these characteristics, a shader that incorporates object-based silhouette detection and a non-uniform point displacement algorithm is proposed. Chapter 4 discusses the development of the shader to generate ornamentation for rendering Wayang Beber characters’ textiles patterns. The characters of Wayang Beber have many characteristic patterns on their textiles. These patterns would require plenty of hard work during the 3DCG animation production of Wayang Beber. This research proposes a semi-automatic system utilizing a shader that uses procedural pattern generation based on shape grammars. Using this system, artists can easily create and modify details of the pattern including shape, size, quantity, color, and arrangement. Chapter 5 discusses key pose extraction and interpolation of in-between frames for animating CG characters made from Wayang Beber of Pacitan paintings. A Wayang Beber painting is a still image that does not have motion from it. Therefore, it appears that it would be very difficult to make a cartoon movie. However, P. Tabrani showed in his study that the essence of motion does exist in these historical paintings. In this research, a new technique was established using the theory developed in Tabrani’s study and the author have succeeded in extracting key poses from Wayang Beber of Pacitan works. Next, in-between frames are needed for the purpose of making a cartoon movie from the extracted key poses. The interpolation in this research is based on the principles of Wayang motion. The principles are derived from movements in other types of Wayang performances, such as Wayang Orang and Wayang Kulit. Using the method proposed in this research, the key frames and in-between frames for animating the characters are able to be provided adequately. Chapter 6 contains the conclusion and the summary of this research. The quality of digital eproductions of traditional drawings using this 3DCG system and the usability of this system are checked and evaluated. Using the methods proposed in this research, it is possible to create 3DCG animations from other types of Wayang Beber. The author intends to propose this 3DCG system to the Indonesian government as a tool for the preservation of traditional theater art in order that this research can contribute to the survival of cultural heritages in Indonesia.首都大学東京, 2015-09-30, 博士(芸術工学）首都大学東