Interactive Illustrative Rendering on Mobile Devices

Scientists, engineers, and artists regularly use illustrations in design, training, and education to display conceptual information, describe problems, and solve those problems. Researchers have developed many advanced rendering techniques on desktop platforms to facilitate illustration generation, but adapting these techniques to mobile platforms has not been easy. We discuss how advanced illustrative rendering techniques, such as interactive cutaway views, ghosted views, silhouettes, and selective rendering, have been adapted to mobile devices. We also present MobileVis, our interactive, illustrative 3D graphics and text rendering system that lets users explore 3D models' interior structures, display parts annotations, and visualize instructions, such as assembly and disassembly procedures for mechanical models     

A General Illumination Model for Molecular Visualization

Several visual representations have been developed over the years to visualize molecular structures, and to enable a better understanding of their underlying chemical processes. Today, the most frequently used atom‐based representations are the Space‐filling, the Solvent Excluded Surface, the Balls‐and‐Sticks, and the Licorice models. While each of these representations has its individual benefits, when applied to large‐scale models spatial arrangements can be difficult to interpret when employing current visualization techniques. In the past it has been shown that global illumination techniques improve the perception of molecular visualizations; unfortunately existing approaches are tailored towards a single visual representation. We propose a general illumination model for molecular visualization that is valid for different representations. With our illumination model, it becomes possible, for the first time, to achieve consistent illumination among all atom‐based molecular representations. The proposed model can be further evaluated in real‐time, as it employs an analytical solution to simulate diffuse light interactions between objects. To be able to derive such a solution for the rather complicated and diverse visual representations, we propose the use of regression analysis together with adapted parameter sampling strategies as well as shape parametrization guided sampling, which are applied to the geometric building blocks of the targeted visual representations. We will discuss the proposed sampling strategies, the derived illumination model, and demonstrate its capabilities when visualizing several dynamic molecules.     

Visual dynamic model based on self-organizing maps for supervision and fault detection in industrial processes

Visual data mining techniques have experienced a growing interest for processing and interpretation of the large amounts of multidimensional data available in current industrial processes. One of the approaches to visualize data is based on self-organizing maps (SOM), which define a projection of the input space onto a 2D or 3D space that can be used to obtain visual representations. Although these techniques have been usually applied to visualize static relations among the process variables, they have proven to be very useful to display dynamic features of the processes. In this work, an approach based on the SOM to model the dynamics of multivariable processes is presented. The proposed method identifies the process conditions (clusters) and the probabilities of transition among them, using the trajectory followed by the input data on the 2D visualization space. Furthermore, a new method of residual computation for fault detection and identification that uses the dynamic information provided by the model of transitions is proposed. The proposed method for modeling and fault identification has been applied to supervise a real industrial plant and the results are included.     

An Evaluation of Visualization Techniques to Illustrate Statistical Deformation Models

As collections of 2D/3D images continue to grow, interest in effective ways to visualize and explore the statistical morphological properties of a group of images has surged. Recently, deformation models have emerged as simple methods to capture the variability and statistical properties of a collection of images. Such models have proven to be effective in tasks such as image classification, generation, registration, segmentation, and analysis of modes of variation. A crucial element missing from most statistical models has been an effective way to summarize and visualize the statistical morphological properties of a group of images. This paper evaluates different visualization techniques that can be extended and used to illustrate the information captured by such statistical models. First, four illustration techniques are described as methods to summarize the statistical morphological properties as captured by deformation models. Second, results of a user study conducted to compare the effectiveness of each visualization technique are presented. After comparing the performance of 40 subjects, we found that statistical annotation techniques present significant benefits when analyzing the structural properties of a group of images.     

Novel Uses of Pinch Gloves™ for Virtual Environment Interaction Techniques

The usability of three-dimensional (3D) interaction techniques depends upon both the interface software and the physical devices used. However, little research has addressed the issue of mapping 3D input devices to interaction techniques and applications. This is especially crucial in the field of Virtual Environments (VEs), where there exists a wide range of potential 3D input devices. In this paper, we discuss the use of Pinch Gloves™ – gloves that report contact between two or more fingers – as input devices for VE systems. We begin with an analysis of the advantages and disadvantages of the gloves as a 3D input device. Next, we present a broad overview of three novel interaction techniques we have developed using the gloves, including a menu system, a text input technique, and a two-handed navigation technique. All three of these techniques have been evaluated for both usability and task performance. Finally, we speculate on further uses for the gloves.     

Visualizing a sphere eversion

The mathematical process of everting a sphere (turning it inside-out allowing self-intersections) is a grand challenge for visualization because of the complicated, ever-changing internal structure. We have computed an optimal minimax eversion, requiring the least bending energy. Here, we discuss techniques we used to help visualize this eversion for visitors to virtual environments and viewers of our video The Optiverse.     

Extending distortion viewing from 2D to 3D

Addresses the visual exploration of 3D information layouts. Several visual exploration techniques have been proposed for 2D information layouts. Many of these try to take advantage of humans' natural visual pattern-recognition abilities to understand global relationships while simultaneously integrating this knowledge with local details. This desire for detail-in-context views (also called fisheye, multiscale and distortion views) has fueled considerable research in the development of distortion viewing tools. Generally, these tools provide space for magnification of local detail by compressing the rest of the image. In considering a possible detail-in-context view for 3D layouts, we first examine 2D distortion techniques, bearing in mind the particular 3D problem of occlusion. Comparing 2D and 3D information layout adjustment tools leads directly to a 3D visual access tool that clears a line of sight to any region of interest. While our technique can extend to any type of 3D information display, we focus on graphs     

The analytic structure of image flows: Deformation and segmentation

Time-varying imagery is often described in terms of image flow fields (i.e., image motion), which correspond to the perceptive projection of feature motions in three dimensions (3D). In the case of multiple moving objects with smooth surfaces, the image flow possesses an analytic structure that reflects these 3D properties. This paper describes the analytic structure of image flow fields in the image space-time domain, and its use for segmentation and 3D motion computation. First we discuss thelocal flow structure as embodied in the concept ofneighborhood deformation. The local image deformation is effectively represented by a set of 12 basis deformations, each of which is responsible for an independent deformation. This local representation provides us with sufficient information for the recovery of 3D object structure and motion, in the case of relative rigid body motions. We next discuss theglobal flow structure embodied in the partitioning of the entire image plane intoanalytic regions separated byboundaries of analyticity, such that each small neighborhood within the analytic region is described in terms of deformation bases. This analysis reveals an effective mechanism for detecting the analytic boundaries of flow fields, thereby segmenting the image into meaningful regions. The notion ofconsistency which is often used in the image segmentation is made explicit by the mathematical notion ofanalyticity derived from the projection relation of 3D object motion. The concept of flow analyticity is then extended to the temporal domain, suggesting a more robust algorithm for recovering image flow from multiple frames. Finally, we argue that the process of flow segmentation can be understood in the framework of grouping process. The general concept ofcoherence orgrouping through local support (such as the second-order flows in our case) is discussed.     

FieldVis: A Tool for Visualizing Astrophysical Magnetohydrodynamic Flow

Astronomers have long been challenged to test theories of observable phenomena at great distances from Earth. One such area of active research is the study of fast, collimated jets of ionized matter, or plasma, formed near massive black holes at the centers of distant galaxies. Our group is involved in magnetohydrodynamic simulations that track the time and space evolution of the full 3D velocity and magnetic vector fields, plus fundamental scalar fields such as density and pressure. To accomplish the complex visualization of these jets, we developed FieldVis, a simulation tool that focuses primarily on representing 3D vector and scalar fields. Examining data from a sample 3D magnetohydrodynamic fluid simulation graphically illustrates the usefulness of our visualization package. Through our work, we found that streaklines with varying surface properties such as texture and color are the most effective way to extract information from our data. The techniques we used are not specific to astrophysical problems and can extend to other sets of vector and scalar fields. In the future, we plan to use FieldVis to visualize tangled magnetic fields in simulated galaxy clusters, as well as velocity and magnetic structures produced by intermittent jets     

大型关系数据集中高维数据可视化处理的一种方法

本文针对大型关系数据集的高维数据,提出了一种基于聚类指引旅行的三维投影的可视化方法.将数据集中的数据聚类,选择聚类的中心点进行投影,将投影映射到三维空间的四面体中,然后将所有的四面体旅行一遍,从而实现数据的遍历和可视化.     

Visual learning of patterns and objects

We discuss automatic rule generation techniques for learning relational properties of 2D visual patterns and 3D objects from training samples where the observed feature values are continuous. In particular, we explore a conditional rule generation method that defines patterns (or objects) in terms of ordered lists of bounds on unary (pattern part) and binary (part relation) features. The technique, termed conditional rule generation, was developed to integrate relational structure representations of patterns and the generalization characteristics of evidenced-based systems. We show how this technique can be used for recognition of complex patterns and of objects in scenes. Further, we show the extent to which the learned rules can identify patterns and objects that have undergone nonrigid distortions.     

Analysis of an EMST-based path for 3D meshes

For several 3D data applications such as data-hiding or compression, data ordering is a major problem. We need to know how to achieve the same 3D mesh path between the coding and decoding stages. Various algorithms have been proposed in recent years, but we focus on methods based on Euclidean Minimum Spanning Trees (EMST). In this paper, we analyse the sensitivity of the EMST structure to obtain a more robust synchronization. We present a new theoretical analysis and a way to visualize EMST robustness. Moreover, this analysis can be useful in 3D data-hiding in order to detect fragile area and to predict the 3D object robustness during transmission on a noisy channel.     

WebQuery: searching and visualizing the Web through connectivity

Finding information located somewhere on the World-Wide Web is an error-prone and frustrating task. The WebQuery system offers a powerful new method for searching the Web based on connectivity and content. We do this by examining links among the nodes returned in a keyword-based query. We then rank the nodes, giving the highest rank to the most highly connected nodes. By doing so, we are finding “hot spots” on the Web that contain information germane to a user's query. WebQuery not only ranks and filters the results of a Web query, it also extends the result set beyond what the search engine retrieves, by finding “interesting” sites that are highly connected to those sites returned by the original query. Even with WebQuery filtering and ranking query results, the result sets can be enormous. So, we need to visualize the returned information. We explore several techniques for visualizing this information—including cone trees, 2D graphs, 3D graphs, lists, and bullseyes-and discuss the criteria for using each of the techniques.     

Time-dependent 3D Data Sets Rendering: an Extension of the Morphing Technique

Morphing is one of the most well-used techniques for producing intermediate images which fill the gap between two stages of a displayed data set. Several 3D morphing methods have been developed for interpolating between synthetic data sets, but none have yet been devised for interpolating between scientific data sets. One of the morphing techniques used for such data sets in 2D is the segment warping algorithm. In this paper, we show that this technique can be extended to 3D data sets. The 3D morphing technique, which is composed of three modules (tweening, warping and dissolving) is first described and then applied to digital volumes (chromosomes at different stages of the cell mitosis) recorded by confocal microscopy. From the intermediate digital volumes created by this technique, movies are produced, which can help in the understanding of the dynamical behaviour of the 3D structure.     

GeoWall: Stereoscopic Visualization for Geoscience Research and Education

The GeoWall lets people visualize the structure and dynamics of the Earth in stereo, aiding their understanding of spatial relationships. Making use of inexpensive, polarized 3D glasses, entire classrooms or conference audiences can share the 3D experience. Since the hardware is portable, it's easy to bring visualizations to the audience. In this article we describe the GeoWall hardware and software and discuss how the GeoWall Consortium was instrumental in creating a community of users in a variety of disciplines. Using case studies, we show how the GeoWall helped research and education. Finally, we describe our recent work in high-resolution tiled displays     

A Survey of Flattening‐Based Medical Visualization Techniques

In many areas of medicine, visualization research can help with task simplification, abstraction or complexity reduction. A common visualization approach is to facilitate parameterization techniques which flatten a usually 3D object into a 2D plane. Within this state of the art report (STAR), we review such techniques used in medical visualization and investigate how they can be classified with respect to the handled data and the underlying tasks. Many of these techniques are inspired by mesh parameterization algorithms which help to project a triangulation in ?³ to a simpler domain in ?². It is often claimed that this makes complex structures easier to understand and compare by humans and machines. Within this STAR we review such flattening techniques which have been developed for the analysis of the following medical entities: the circulation system, the colon, the brain, tumors, and bones. For each of these five application scenarios, we have analyzed the tasks and requirements, and classified the reviewed techniques with respect to a developed coding system. Furthermore, we present guidelines for the future development of flattening techniques in these areas.     

i-PI: A Python interface for ab initio path integral molecular dynamics simulations

Recent developments in path integral methodology have significantly reduced the computational expense of including quantum mechanical effects in the nuclear motion in ab initio molecular dynamics simulations. However, the implementation of these developments requires a considerable programming effort, which has hindered their adoption. Here we describe i-PI, an interface written in Python that has been designed to minimise the effort required to bring state-of-the-art path integral techniques to an electronic structure program. While it is best suited to first principles calculations and path integral molecular dynamics, i-PI can also be used to perform classical molecular dynamics simulations, and can just as easily be interfaced with an empirical forcefield code. To give just one example of the many potential applications of the interface, we use it in conjunction with the CP2K electronic structure package to showcase the importance of nuclear quantum effects in high-pressure water.     

Multiscale volume representation by a DoG wavelet

This article presents a method for decomposing volume data into 3D DoG (difference of Gaussians) functions by using the frame theory of nonorthogonal wavelets. Since we can think of a DoG function as a pair of Gaussian functions, we can consider this method an automatic generation of Blinn's blobby objects (1982). We can also use this representation method for data compression by neglecting the insignificant coefficients, since the wavelet coefficients have significant values only where the volume density changes. Further, since the DoG function closely approximates a ∇²G (Laplacian of Gaussian) function, the representation can be considered a hierarchy of the 3D edges on different resolution spaces. Using the spherically symmetric feature of the 3D DoG function, we can easily visualize the 3D edge structure by the density reprojection method. We apply our representation method to medical CT volume data and show its efficiency in describing the spatial structure of the volume