In most interactive systems, the handling of text and images are still quite separate matters. Rendering pipelines handle 2D and 3D graphics, while text tends to be an after-thought which is hardly integrated at the system level, let alone at the level of user interaction.This talk will survey recent developments in the area of image-text interaction from both the system architecture point of view and with respect to user interfaces. The talk will emphasize interactive labelling of 2D and 3D graphics and outline new real-time algorithms for label placement. Labelled images will be discussed as an interface to methods and tools for data mining. Finally, challenges for future developments in the area of image-text interaction will be outlined.

Textual annotations are important elements in all but the simplest visual interfaces. In order to integrate textual annotations smoothly into the dynamic graphical content of interactive information systems, fast yet high-quality label layout algorithms are required. With the ongoing pervasion of mobile applications these requirements are shifted from workstations to comparatively low-performance mobile devices. Fortunately, ubiquitous network access is also on the advance, so that mobile applications can employ remote layout services on external workstations. This paper presents two novel label layout algorithms for relevance-driven dynamic visualizations in interactive information systems. They are employed to generate adaptive visualizations in a mobile maintenance support scenario

Abstract The termstroke‐based renderingcollectively describes techniques where images are generated from elements that are usually larger than a pixel. These techniques lend themselves well for rendering artistic styles such as stippling and hatching. This paper presents a novel approach for stroke‐based rendering that exploits multi‐agent systems. RenderBots are individual agents each of which in general represents one stroke. They form a multi‐agent system and undergo a simulation to distribute themselves in the environment. The environment consists of a source image and possibly additional G‐buffers. The final image is created when the simulation is finished by having each RenderBot execute its painting function. RenderBot classes differ in their physical behavior as well as their way of painting so that different styles can be created in a very flexible way.

Understanding complex 3D virtual models can be difficult, especially when the model has interior components not initially visible and ancillary text. We describe new techniques for the interactive exploration of 3D models. Specifically, in addition to traditional viewing operations, we present new text extrusion techniques combined with techniques that create an interactive explosion diagram. In our approach, scrollable text annotations that are associated with the various parts of the model can be revealed dynamically, either in part or in full, by moving the mouse cursor within annotation trigger areas. Strong visual connections between model parts and the associated text are included in order to aid comprehension. Furthermore, the model parts can be separated, creating interactive explosion diagrams. Using a 3D probe, occluding objects can be interactively moved apart and then returned to their initial locations. Displayed annotations are kept readable despite model manipulations. Hence, our techniques provide textual context within the spatial context of the 3D model.

Abstract Hatching lines are often used in line illustrations to convey tone and texture of a surface. In this paper we present methods to generate hatching lines from polygonal meshes and render them in high quality either at interactive rates for on‐screen display or for reproduction in print. Our approach is based on local curvature information that is integrated to form streamlines on the surface of the mesh. We use a new algorithm that provides an even distribution of these lines. A special processing of these streamlines ensures high quality line rendering for both intended output media later on. While the streamlines are generated in a preprocessing stage, hatching lines are rendered either for vector‐based printer output or on‐screen display, the latter allowing for interaction in terms of changing the view parameters or manipulating the entire line shading model at run‐time using a virtual machine. Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Picture/Image Generation—Display algorithms; I.3.3 [Computer Graphics]: Picture/Image Generation—Line and curve generation image

Many exploration and manipulation tasks benefit from a coherent integration of multiple views onto complex information spaces. This paper proposes the concept of Illustrative Shadows for a tight integration of interactive 3D graphics and schematic depictions using the shadow metaphor. The shadow metaphor provides an intuitive visual link between 3D and 2D visualizations integrating the different displays into one combined information display. Users interactively explore spatial relations in realistic shaded virtual models while functional correlations and additional textual information are presented on additional projection layers using a semantic network approach. Manipulations of one visualization immediately influence the others, resulting in an in-formationally and perceptibly coherent presentation

The notable amount and variation of current techniques in non-photorealistic rendering (NPR) indicates a level of maturity whereby the categorization of algorithms has become possible. We present a conceptual model for NPR, on which we base a modular system, OPENNPAR, which integrates NPR algorithms into distinct classes. Components in OPENNPAR are modularized and consequently reintegrated for various rendering purposes, allowing many kinds of NPR algorithms to be reproduced, including the integration of 2D and 3D methods. Additionally, the system provides support for a range of users (developers, programmers, designers) according to their respective levels of abstraction, thus being available in multiple contexts. Ultimately, OPENNPAR holds great potential as a tool in the development, augmentation, and creation of NPR effects.

Digital watermarking is a technique for embedding information into data, such as images, 3D models, or audio files, such that some properties (i.e., security, imperceptibility, robustness) are maintained. While most of the existing watermarking techniques focus on encoding copyright information where security is one of the most important properties, we have developed algorithms for embedding Illustration Watermarking, i.e., content-related annotations for the image. Robustness against common media transformations, high capacity, and blind detection are our aspired properties while security and the usage of secure keys are less important. The medium that we are using for embedding data are 2D vector graphics. We introduce algorithms that change line attributes, introduce new vertices in certain patterns, and replace existing stroke segments by new lines in a stylistic way. Based on the modification they introduced, we categorize our techniques into whether they change the appearance of the image or not and whether the changes are perceivable by the naked eye or not. We demonstrate our techniques with silhouette lines obtained from 3D models. Such line drawings are a very common style utilized in many illustrations, in particular in the medical and technical domain.

We introduce a new method to automatically and dynamically illustrate arbitrary texts from a predefined application domain. We demonstrate this method with two experimental systems (Text Illustrator and Agi 3 le) which are designed to illustrate anatomy textbooks. Both systems exploit a symbolic representation of the content of structured geometric models. In addition, the approach taken by the Agi 3 le-system is based on an ontology providing a formal representation of important concepts within the application domain as well as a thesaurus containing alternative linguistic and visual realizations for entities within the formal domain representation. The presented method is text-driven, i.e., an automated analysis of the morphologic, syntactic and semantic structures of noun phrases reveals the key concepts of a text portion to be illustrated. The specific relevance of entities within the formal representation is determined by a spreading activation approach. This allows to derive important parameters for a non-photorealistic rendering process: the selection of suitable geometric models, camera positions and presentation variables for individual geometric objects. Part-whole relations are considered to assign visual representations to elements of the formal domain representation. Presentation variables for objects in the 3D rendering are chosen to reflect the estimated relevance of their denotation. As a result, expressive non-photorealistic illustrations which are focussed on the key concepts of individually selected text passages are generated automatically. Finally, we present methods to integrate user interaction within both media, the text and the computer-generated illustration, in order to adjust the presentation to individual information seeking goals.

Dual-Use of Image Space (DUIS) is a new technique for presenting text explanations for images within image space. This, however presents the problem of readability of the text since readers are used to reading from rectangular windows, on the other hand, a graphical object will typically have a silhouette of an irregular shape. To improve the readability we have developed a technique called rectangularization, i.e. on users' request the selected object morphs into a rectangular window. In order to preserve the context for the rectangularized object, as the selected object morphs into a rectangle, the other objects in the scene also change shape to create room for the newly created rectangle. On top of discussing the rectangularization concept, this paper discusses the algorithm used to displace the other objects in the scene. We also show the extension of the algorithms to allow for multiple rectangularization.

A way to create effective stylized line drawings is to draw strokes that start and stop at visible portions along the silhouette of an object to be portrayed. In computer graphics to date, algorithms to extract silhouette edges are many, although putting these edges into a form such that stylized strokes may be applied to them has not been greatly covered, so that existing methods are either time-consuming or presented vaguely. In this paper, we introduce an algorithm that takes a set of silhouette edges originating from polygonal meshes and efficiently computes the visible parts of the edges before connecting them to form long smooth silhouette strokes to which stylization algorithms may be effectively applied. Features of our algorithm that gain efficiency and accuracy over existing methods is that we directly exploit the analytic connectivity information of the mesh in combination with the available z-buffer information during rendering, and filter artifacts in connected edges during the process to improve the visual quality of strokes after stylization. Categories and Subject Descriptors (according to ACM CCS): 1.3.3 [Computer Graphics]: Picture/Image Generation—Line and curve generation 1.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism—Hidden line/surface removal

Exploring unknown models or scenes is a highly interactive and dynamic process. Systems for automatic presentation of models or scenes either require cinematographic rules, direct human interaction, framesets, or pre‐calculation of paths to a known goal. In this paper we present a system which can deal with rapidly changing user interest in objects of a scene or model as well as with dynamic models and changes of the camera position introduced interactively by the user or through cuts. We describe CubicalPath, a new potential field‐based camera control system that helps with the exploration of virtual environments.

Many computer games treat the user in the “1st person” and bind the camera to his or her view. More sophistication in a game can be achieved by enabling the camera to leave the users' viewpoint. This, however, requires new methods for automatic, dynamic camera control. In this paper we present methods and tools for such camera control. We emphasize guiding camera control by constraints; however, optimal constraint satisfaction tends to lead to the camera jumping around too much. Thus, we pay particular attention to a trade-off between constraint satisfaction and frame coherence. We present a new algorithm for dynamic consideration of the visibility of objects which are deemed to be important in a given game context.

When blind people wish to walk through an area not fully known to them, they have to prepare themselves even more thoroughly than sighted pedestrians. We propose a new approach to support this preparation with the help of an interactive computer method, called constructive exploration. Using this method, the user is guided in physically constructing the spatial arrangement to be learned using building blocks. We describe two implementations of the concept, one with a graspable interface with object tracking and the other employing a force feedback device. We report on first tests of the implementations.

Most illustrative techniques used in non-photorealistic rendering to date apply a rendering style to objects or a scene and alter the appearance of this style by employing illumination or depth cueing. However for generating high quality illustrations this approach relies almost entirely on smart placement of light sources. We introduce the concept of illustrative effects to describe the workings of illustrative techniques that rely on spatial location rather than just illumination or depth. Although the rendering style is still object-dependent, this technique allows us to visualize or emphasize parts of objects or the whole scene without being limited by the scene's object decomposition. The approach also enforces the decoupling of the model and its animation from the visualization task. We demonstrate our approach using a sample collection of illustrative effects applied to line drawings. A uniform set of tools to manipulate these effects is provided.

Exploring unknown models or scenes is a highly interactive and dynamic process. Systems for automatic presentation of models or scenes either require cinematographic rules, direct human interaction, framesets or precalculation of paths to a known goal. We are looking for a system which can deal with rapidly changing user interest in objects of a scene or model as well as with dynamic models and changes of the camera position introduced interactively by the user or through cuts. In this paper we describe CubicalPath, a new potential field-based camera control system that helps with the exploration of virtual environments.

We present a method for automatically rendering pen-and-ink illustrations of trees. A given 3-d tree model is illustrated by the tree skeleton and a visual representation of the foliage using abstract drawing primitives. Depth discontinuities are used to determine what parts of the primitives are to be drawn; a hybrid pixel-based and analytical algorithm allows us to deal efficiently with the complex geometric data. Using the proposed method we are able to generate illustrations with different drawing styles and levels of abstraction. The illustrations generated are spatial coherent, enabling us to create animations of sketched environments. Applications of our results are found in architecture, animation and landscaping.

We present a method for computer generated pen‐and‐ink illustrations by the simulation of stippling. In a stipple drawing, dots are used to represent tone and also material of surfaces. We create such drawings by generating an initial dot set which is then processed by a relaxation method based on Voronoi diagrams. The point patterns generated are approximations of Poisson disc distributions and can also be used for integrating functions or the positioning of objects. We provide an editor similar to paint systems for interactively creating stipple drawings. This makes it possible to create such drawings within a matter of hours, instead of days or even weeks when the drawing is done manually.

One of the assumptions of current software for visualizing architecture is that the underlying geometry is a correct, objective and complete representation of the objects in question. However, we argue that such an ideal situation can hardly be met. Instead, there are a variety of situations in which there is considerable uncertainty associated with some features of a model. Furthermore, the model usally stems from design decisions which are not encoded in the model but which may be important for users. We argue that more information about geometric models should be representable and visualizable. In particular, we propose non-photorealistic rendering styles for encoding such additional information in a visualization of a 3D model which goes over and above the geometry. We then apply this concept to visualizations of virtual reconstructions of ancient architecture. Finally, we describe the prototypical system AncientVis, which represents an approach to visualizing models with uncertain features.

In synthetic holography, the emphasis has been on numerical simulation methods for the recording and reconstruction processes, but methods to visualize the calculated results are yet underdeveloped. We show how volume slicing and volume rendering using a threshold for translucency can be applied to synthetic holography. Results of the three-dimensional visualization of the reconstruction are presented, thereby illustrating the usefulness of the threshold operator.

Rendering high‐quality non‐photorealistic images of a given geometric model is often associated with a considerable amount of effort on the part of a user to fine‐tune the rendition. In this paper we introduce a method and tools for re‐using the user's effort invested in one model for the rendering of other models. Our method uses templates to describe rendition styles. The paper gives a number of examples of the successful transfer of styles from one model to another.

We present a general concept for the enhancement of visual interfaces with automatic figure captions describing a visualization. The incorporation of figure captions in interactive systems raises some fundamentally new questions as these images are exposed to changes. The dynamic aspects to be considered include the update and customization of figure captions.We employ figure captions not only for the description of images but also for their modification leading to the introduction of interactive figure captions. A general architecture is developed and comprehensively described referring to two application domains: medical illustrations and geographic maps.

This paper builds on the principles of depicting transparency in hand-made line drawings, and develops a method to generate similar, but computer-generated, line drawings in a two-step process. In the first step, a brightness image is generated, which is used as a basis for the line drawing created in the second step. Three different methods derived from traditional drawing techniques are shown.

Presents a visualisation of a medieval palace as an application for a new rendering and animation tool which is capable of rendering images in the style of line drawings. In contrast to other systems, we are able to generate frame-to-frame coherent line drawings in order to render an animation. The application of this presentation illustrates the capabilities of animated line drawings and makes use of different drawing techniques, such as simplifying a scene and emphasising important objects.

Holography is a method for three dimensional imaging of objects. We present an approach for the generation of holograms, exploiting standard graphics rendering methods and hardware. We focus on the visualization of objects composed of line segments, which allow for certain simplifications, and thus hologram generation speedup. Our method is based on the derivation of a holographic geometric equivalent of the object to be imaged. In this equivalent, the object is represented as a set of geometric primitives combined with precomputed textures. The equivalent is built up under prescribed conditions, thus simulating certain wave characteristics. The hologram of the object to be imaged is gained just by rendering its holographic geometric equivalent. Problems of achieving the necessary resolution of the output hologram are addressed.

Article Free Access Share on Assessing the effect of non-photorealistic rendered images in CAD Authors: Jutta Schumann Free University of Berlin, Dept. of Computer Science Takustraβe 9 D-14195 Berlin Free University of Berlin, Dept. of Computer Science Takustraβe 9 D-14195 BerlinView Profile , Thomas Strothotte University of Magdeburg, Dept. of Simulation and Graphics Universitätsplatz 2D-39106, Magdeburg University of Magdeburg, Dept. of Simulation and Graphics Universitätsplatz 2D-39106, MagdeburgView Profile , Stefan Laser University of Magdeburg, Dept. of Psychology Virchowstraβe 24 D-39104 Magdeburg University of Magdeburg, Dept. of Psychology Virchowstraβe 24 D-39104 MagdeburgView Profile , Andreas Raab University of Magdeburg, Dept. of Simulation and Graphics Universitätsplatz 2D-39106, Magdeburg University of Magdeburg, Dept. of Simulation and Graphics Universitätsplatz 2D-39106, MagdeburgView Profile Authors Info & Claims CHI '96: Proceedings of the SIGCHI Conference on Human Factors in Computing SystemsApril 1996 Pages 35–41https://doi.org/10.1145/238386.238398Published:13 April 1996Publication History 68citation1,283DownloadsMetricsTotal Citations68Total Downloads1,283Last 12 Months104Last 6 weeks14 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteView all FormatsPDF

Abstract Rendering systems generally treat the production of images as an objective process governed by the laws of physics. However, perception and understanding on the part of viewers are subjective processes influenced by a variety offactors. For example, in the presentation of architectural drawings, the apparent precision with which the drawings are made will affect whether the viewer considers the design as part of a preliminary design or as part of a final polished project, and to some extent the level of confidence the viewer has in the encoded information. In this paper we develop techniques for rendering images in a way that differs from the usual photorealistic or wire‐frame output of renderers. In particular, our techniques allow a user to adjust the rendering of a scene to produce images using primitives with variable degrees of precision, from approximations that resemble vague “five‐minute‐sketches” to more mature but still hand‐drawn images. We provide a theoretical framework for analysing the information flow from the computer to the user via such images. Finally, we describe the design and implementation of a prototypical renderer and show examples of its output.

Abstract Parallel processing algorithms have been developed which approach real‐time in displaying raster graphics images of a single rotating three‐dimensional object. The hardware required consists of a large number of individual processors with inter‐processor communication restricted to immediate neighbours. The overall structure is as if the processors were spread uniformly over the surface of a sphere. The objects for display are modelled as if they were inside this sphere of processors. Each processor stores the following information: the intersection points of the object's surface with a radial line extended from the sphere's centre along with the surface normals at those intersection points, and pixels representing a small section of the screen. The algorithm involves an organised message‐passing scheme to accomplish rotations of the object description and the subsequent display of the image. A simulation of a system involving several hundred processors indicates that its performance improves as a near‐linear function of the number of processors.