Published papers

Blazars are attractive objects for astronomers to observe in order to burrow into the magnetic field in the relativistic jet. This paper presents TimeTubes as a novel visualization scheme that allows astronomers to interactively explore characteristic temporal variation patterns in observed blazar datasets. In the TimeTubes spatialization, the two Stokes parameters and their errors with a common timestamp are transformed into an ellipse. A series of such ellipses are aligned in parallel along the timeline to form a 3D volumetric tube. The resulting tube is then colorized by the observed intensities and colors of the blazar, and finally volume-rendered. A designated user interface is provided with visual exploration functions according to Shneiderman's Visual Information Seeking Mantra. In the latest version, an auxiliary mechanism, called visual data fusion, was incorporated to ameliorate data- and mapping-inherent uncertainties for more efficient and effective visual exploration.

A viewer is likely to see the large display content with a distorted geometry which differs in accordance with his individual standing position. This problem makes it difficult for the viewer to understand the large display content correctly. In particular, when such a large display is used as digital signage advertisement, this problem has negative influences on its advertising effect. On top of that, in most cases, passengers do not originally have interests in the digital signage content, and thus it is not proper to ask them to move to appropriate positions, though this is suggested in previous studies. We, therefore, propose a novel method which can deliver the content only with little distortion to each passenger without requiring voluntary moves and times. Specifically, the method automatically detects each passenger’s position and adaptively reconfigures the large display content geometry and layout as if the content were rotated toward the positions. We implemented a large display system with the proposed method and evaluated the effectiveness of our method.

The term figurative refers to any form of mathematical visualization that retains strong references to the geometry found in the real world. This paper explains the figuration process for some basic mathematical functions definable in the n-dimensional complex projective space. In the latter part of this paper, we raise a question that has been neglected thus far: What does the Riemann sphere’s axis stand for? We show that the answer can be obtained only by observing from the inside the sphere by setting the viewpoint of the immersive environment to the origin, which is always undefined in projective geometry. We also draw some basic math functions that are familiar to us on the projective plane and observe the invariant properties that exist among the functions, which were thought to be different from one another.

With the improvements of telescopes and proliferation of sky surveys, there is always more astrophysical data to analyze, but not so many astronomers. We present aflak, a visualization environment to analyze astronomical datasets. This paper’s contribution lies in that we leverage visual programming techniques to conduct fine-grained astronomical transformations, filtering and visual analyses on multispectral datasets, with the possibility for astronomers to interactively fine-tune all the interacting parameters. As the visual program is gradually designed, the computed results can be visualized in real time, thus aflak puts the astronomer in the loop, while managing data provenance at the same time.

Blazars are attractive objects for astronomers to observe in order to demystify the relativistic jet. Astronomers need to classify characteristic temporal variation patterns and correlations of multidimensional time-dependent observed blazar datasets. Our visualization scheme, called TimeTubes, allows them to easily explore and analyze such datasets geometrically as a 3D volumetric tube. Even with TimeTubes, however, data analysis over such long-term datasets costs them so much labor and may cause a biased analysis. This paper, therefore, attempts to incorporate into the current prototype of TimeTubes, a new functionality: feature extraction, which supports astronomers’ efficient data analysis by automatically extracting characteristic spatiotemporal subspaces.

Color vision deficiency (CVD), also known as color blindness, is commonly caused by genetic disorder. Unfortunately, as of 2018, there is not yet a cure for the condition. Contact lenses and glasses with color filter are possible solutions to CVD by applying uniform changes to user’s field of view (FoV). On the other hand, optical see-through head-mounted display (OST-HMD) can provide a controllable overlay to user’s FoV, which could help for making a better solution. To calibrate colors in FoV of a user with CVD, methods that often used, such as the daltonization process, need light reduce feature, which makes calibrated color darker. However, recent commercially available OST-HMDs don’t have a controllable way to decrease the brightness of incoming light. In this paper, we present an approach for light subtraction of OSTHMD using a transmissive LCD panel. A prototype system for achieving a controllable overlay to user’s FoV with OST-HMD by using scene camera, user-perspective camera, and the transmissive LCD panel was implemented.

There are many opportunities to draw human hands in computer graphics. The motion of internal organs within a human hand has a non-negligible effect on the natural change in the appearance of the hand’s surface. In this work, we propose a method for expressing this change interactively with the use of an implicit model of a human hand that has semi-natomical structures. The model is referred to as Fast, Implicit model with Semi-anatomical sTructures or FIST. In the FIST model, bones are modeled anatomically based on computed tomography imaging, while soft tissues are modeled artificially. It can be controlled only by specifying the angles of the joints. The proposed method can contribute to a compelling expression of the dynamism in such hand motions as grasping, pinching, and scratching in immersive virtual reality and games.

In role-playing games, creators always use specific models to generate non-player characters (NPCs). The prefabricated models are materialized in the scenes, and if more NPCs are included than character models prepared, the players may easily find many NPCs with similar appearances,which makes the scenes unnatural. In this paper, we propose a novel system for generating a rich variety of 3D anime-like NPCs in real time to make the scenes look more natural. We combine a proprietary character customization system with machine learning, where the customizing parameters are treated as feature vectors input in the neural network. The parameters are trained to avoid generating bad-looking models. We demonstrate that the proposed system can generate a natural school classroom scene with a variety of good-looking female student NPCs in a uniform.

© 2019 IEEE. Solving complex data analysis problems can often benefit a collaborative effort. For synchronous co-located collaboration, a well-recognized challenge is to deliver different contents to people with different privileges and different responsibilities. This challenge is becoming more obvious with the use of a shared display space such as a wall-size display. In particular, scenarios often arise that a privileged participant needs to access sensitive information that other participants are not permitted to view. This is nearly impossible to achieve with only a single display. As a result, it becomes clear that additional devices are needed to provide some of the participants the capability to access and manage certain information in a private space. In this work, we investigate incorporating optical see-through head-mounted displays (OST-HMDs) with a wall-size display to deliver sensitive information in a synchronous co-located, collaborative setting. With our prototype system, we conduct a user study to observe the collaboration styles under this unique setup. We also present the lessons learned by reflecting on the iterative design process of our prototype system.

With the advent of the high-performance graphics and networking technologies that enable us to create virtual worlds networked via the Internet, various virtual environments have been developed to support mathematics education. In the environments that have been inherently two- or three-dimensional Euclidean,students have discovered and experienced mathematical concepts and processes in almost the same ways that they can do in real life. We present an immersive virtual environment that allows the user to set environmental limits beyond the Euclidean 3-space while providing a good user experience. The problem here is that the higher the level of mathematics, the more the visualization method tends to become abstract that only experts with advanced degrees can fathom. We also show how our figurative approach is essential for bridging the gap between elementary and more sophisticated mathematical visualizations.

When expressing the temporal change of finely structured clothes, deterioration is an imperative factor of visual simulation. Considering the complexity of their microstructures, a simple and easy way to damage finely structured clothes is required. This paper presents a novel method for modeling clothes with fiber-level details and showing their damages on a ray-tracing basis. Our particular focus is placed on washed jeans, where representative kinds of local deterioration, including cutting of fiber and color fading, affect the entire appearance of the clothes. The plausibility of the proposed method was empirically proven with several modeling and rendering experiments.

The number of individuals with Age-related Macular Degeneration(AMD) is rapidly increasing.One of the main symptoms of AMD is ‟metamorphopsia,” or distorted vision, which not only makes it difficult for individuals with AMD to do detailed-oriented tasks but also makes sufferers more vulnerable to certain risks in day-to-day life. Traditional clinical approaches to assess metamorphopsia have lacked mechanisms for quantifying the degree of distortion in space,making it impossible to know exactly how individuals with the condition see things. This paper proposes a new method for quantifying distortion in space and visualizing AMD patients’ distorted views via line manipulation. By visualizing the distorted views stemming from metamorphopsia, the method gives doctors and others an intuitive picture of how patients see the world and thereby enables a broad range of options for treatment and support.

Visual field defect (VFD) refers to a symptom in which a patient loses part of his/her field of view (FoV). Medical therapy can halt the progression of VFD, but complete recovery is impossible. In this paper, we propose a computational method for alleviating the restricted FoV with an optical see-through headmounted display (OST-HMD), where an overview scene captured by the installed camera is overlaid on the persisting FoV. Because the overview window occludes with the real world scene, there is a trade-off between the augmented contextual information and the local unscreened information. We hypothesized that such a trade-off can be resolved by taking into consideration the size of the overview window and its displacement from the center of the unimpaired FoV. We therefore conducted an empirical evaluation through a Whac-A-Mole type of task with ten VFDimitative subjects, where three sizes of an overview window with a fixed aspect ratio and seven positions in terms of elevation and azimuth were used combinatorially on an OST-HMD to find the best size and position of the overview window. It was statistically proven that for left-sided homonymous VFD-imitative subjects,the performance of the task was better when the medium-sized overview window was placed in the lower right position. The obtained result can legitimate default setting for the proposed VFD alleviation method.

Due to the rise in popularity of video sharing websites, video streaming services, and social networking services,people daily watch many videos on the web. However, viewers do not commonly access their video viewing history for the purpose of self-reflection and self-representation. A previous research addressed the issue of creating visual mementos, or visualizations to be kept as reminders of life experiences from personal digital data. As a new application of the research, in this paper we present a system named rewind, through which users can create visual mementos of their web video viewing experiences to reminisce about and share. The system rewind provides two kinds of visualizations: MapView (2D) and TubeView (3D), both of which are intended to visualize the YouTube video viewing history of a single user by giving plausible meanings to the size and position of thumbnails and directed links between them. These visualizations remind users of their interests and viewing preferences hidden in the watch history. The user interface of rewind is designed with designated visual exploration functions according to Shneiderman’s Visual Information Seeking Mantra.We also employed an anamorphosis-based, naked-eye 3D display technique in order for TubeView to build an immersive environment for facilitating self-reflection. In addition, the system rewind provides the functionalities that are necessary in a visual memento creation tool to express subjectivity toward the past and to share visual mementos with others while hiding sensitive information.