Results 1 - 10 of 187

View management for virtual and augmented reality

by Blaine Bell, Steven Feiner, Tobias Höllerer , 2001
"... We describe a view-management component for interactive 3D user interfaces. By view management, we mean maintaining visual constraints on the projections of objects on the view plane, such as locating related objects near each other, or preventing objects from occluding each other. Our view-manageme ..."
Abstract - Cited by 114 (19 self) - Add to MetaCart
We describe a view-management component for interactive 3D user interfaces. By view management, we mean maintaining visual constraints on the projections of objects on the view plane, such as locating related objects near each other, or preventing objects from occluding each other. Our view-management component accomplishes this by modifying selected object properties, including position, size, and transparency, which are tagged to indicate their constraints. For example, some objects may have geometric properties that are determined entirely by a physical simulation and which cannot be modified, while other objects may be annotations whose position and size are flexible. We introduce algorithms that use upright rectangular extents to represent on the view plane a dynamic and efficient approximation of the occupied space containing the projections of visible portions of 3D objects, as well as the unoccupied space in which objects can be placed to
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Viewpoint Selection using Viewpoint Entropy

by Pere-pau Vazquez, Miquel Feixas, Mateu Sbert, Wolfgang Heidrich , 2001
"... Computation of good viewpoints is important in several fields: computational geometry, visual servoing, robot motion, graph drawing, etc. In addition, selection of good views is rapidly becoming a key issue in computer graphics due to the new techniques of Image Based Rendering. Although there is no ..."
Abstract - Cited by 90 (15 self) - Add to MetaCart
Computation of good viewpoints is important in several fields: computational geometry, visual servoing, robot motion, graph drawing, etc. In addition, selection of good views is rapidly becoming a key issue in computer graphics due to the new techniques of Image Based Rendering. Although there is no consensus about what a good view means in Computer Graphics, the quality of a viewpoint is intuitively related to how much information it gives us about a scene. In this paper we use the theoretical basis provided by Information Theory to define a new measure, viewpoint entropy, that allows us to compute good viewing positions automatically. We also show how it can be used to select a set of N good views of a scene for scene understanding. Finally, we design an algorithm that uses this measure to explore automatically objects or scenes. 1

An Invitation to Discuss Computer Depiction

by Fredo Durand , 2002
"... This paper draws from art history and perception to place computer depiction in the broader context of picture production. It highlights the often underestimated complexity of the interactions between features in the picture and features of the represented scene. Depiction is not always a unidirecti ..."
Abstract - Cited by 63 (4 self) - Add to MetaCart
This paper draws from art history and perception to place computer depiction in the broader context of picture production. It highlights the often underestimated complexity of the interactions between features in the picture and features of the represented scene. Depiction is not always a unidirectional projection from a 3D scene to a 2D picture, but involves much feedback and influence from the picture space to the object space. Depiction can be seen as a pre-existing 3D reality projected onto 2D, but also as a 2D pictorial representation that is superficially compatible with an hypothetic 3D scene. We show that depiction is essentially an optimization problem, producing the best picture given goals and constraints. We introduce a classification of basic depiction techniques based on four kinds of issue. The spatial system deals with the mapping of spatial properties between 3D and 2D (including, but not restricted to, perspective projection). The primitive system deals with the dimensionality and mappings between picture primitives and scene primitives. Attributes deal with the assignment of visual properties such as colors, texture, or thickness. Finally, marks are the physical implementations of the picture (e.g. brush strokes, mosaic cells). A distinction is introduced between interaction and picturegeneration methods, and techniques are then organized depending on the dimensionality of the inputs and outputs.
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View Selection for Volume Rendering

by Udeepta Bordoloi, Han-Wei Shen , 2005
"... In a visualization of a three-dimensional dataset, the insights gained are dependent on what is occluded and what is not. Suggestion of interesting viewpoints can improve both the speed and efficiency of data understanding. This paper presents a view selection method designed for volume rendering. I ..."
Abstract - Cited by 60 (5 self) - Add to MetaCart
In a visualization of a three-dimensional dataset, the insights gained are dependent on what is occluded and what is not. Suggestion of interesting viewpoints can improve both the speed and efficiency of data understanding. This paper presents a view selection method designed for volume rendering. It can be used to find informative views for a given scene, or to find a minimal set of representative views which capture the entire scene. It becomes particularly useful when the visualization process is non-interactive -- for example, when visualizing large datasets or time-varying sequences. We introduce a viewpoint "goodness" measure based on the formulation of entropy from information theory. The measure takes into account the transfer function, the data distribution and the visibility of the voxels. Combined with viewpoint properties like view-likelihood and view-stability, this technique can be used as a guide which suggests "interesting" viewpoints for further exploration. Domain knowledge is incorporated into the algorithm via an importance transfer function or volume. This allows users to obtain view selection behaviors tailored to their specific situations. We generate a view space partitioning, and select one representative view for each partition. Together, this set of views encapsulates the "interesting" and distinct views of the data. Viewpoints in this set can be used as starting points for interactive exploration of the data, thus reducing the human effort in visualization. In non-interactive situations, such a set can be used as a representative visualization of the dataset from all directions.

Intelligent Multi-shot Visualization Interfaces for Dynamic 3D

by William H. Bares, James C. Lester - Worlds, Proceedings of the 1999 International Conference on Intelligent User Interfaces , 1999
"... In next-generation virtual 3D simulation, training, and entertainment environments, intelligent visualization interfaces must respond to user-specified viewing requests so users can follow salient points of the action and monitor the relative locations of objects. Users should be able to indicate wh ..."
Abstract - Cited by 52 (4 self) - Add to MetaCart
In next-generation virtual 3D simulation, training, and entertainment environments, intelligent visualization interfaces must respond to user-specified viewing requests so users can follow salient points of the action and monitor the relative locations of objects. Users should be able to indicate which object(s) to view, how each should be viewed, cinematic style and pace, and how to respond when a single satisfactory view is not possible. When constraints fail, weak constraints can be relaxed or multi-shot solutions can be displayed in sequence or as composite shots with simultaneous viewports. To address these issues, we have developed CONSTRAINTCAM, a real-time camera visualization interface for dynamic 3D worlds. It has been studied in an interactive testbed in which users can issue viewing goals to monitor multiple autonomous characters navigating through a virtual cityscape. CONSTRAINT~AM’S real-time performance in this testbed is encouraging.
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Towards virtual videography

by Rachel Heck, Michael Wallick, Michael Gleicher - Proc. Multimedia’00 , 2000
"... Well-produced videos provide a convenient and effective way to archive lectures. In this article, we offer a new way to create lecture videos that retains many of the advantages of well-composed recordings, without the cost and intrusion of a video production crew. We present an automated system cal ..."
Abstract - Cited by 49 (7 self) - Add to MetaCart
Well-produced videos provide a convenient and effective way to archive lectures. In this article, we offer a new way to create lecture videos that retains many of the advantages of well-composed recordings, without the cost and intrusion of a video production crew. We present an automated system called Virtual Videography that employs the art of videography to mimic videographerproduced videos, while unobtrusively recording lectures. The system uses the data recorded by unattended video cameras and microphones to produce a new edited video as an offline postprocess. By producing videos offline, our system can use future information when planning shot sequences and synthesizing new shots. Using simple syntactic cues gathered from the original video and a novel shot planning algorithm, the system makes cinematic decisions without any semantic understanding of the lecture.
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Expressive Autonomous Cinematography for Interactive Virtual Environments

by Bill Tomlinson, Bruce Blumberg, Delphine Nain - In Proceedings of the Fourth International Conference on Autonomous Agents , 2000
"... We have created an automatic cinematography system for interactive virtual environments. This system controls a virtual camera and lights in a three-dimensional virtual world inhabited by a group of autonomous and user-controlled characters. By dynamically changing the camera and the lights, our sys ..."
Abstract - Cited by 47 (5 self) - Add to MetaCart
We have created an automatic cinematography system for interactive virtual environments. This system controls a virtual camera and lights in a three-dimensional virtual world inhabited by a group of autonomous and user-controlled characters. By dynamically changing the camera and the lights, our system facilitates the interaction of human participants with this world and displays the emotional content of the digital scene. Building on the tradition of cinema, modern video games, and autonomous behavior systems, we have constructed this cinematography system with an ethologically-inspired structure of sensors, emotions, motivations, and action-selection mechanisms. Our system breaks shots into elements, such as which actors the camera should focus on or the angle it should use to watch them. Hierarchically arranged cross-exclusion groups mediate between the various options, arriving at the best shot at each moment in time. Our cinematography system uses the same approach that we use fo...

Artistic composition for image creation

by Bruce Gooch, Erik Reinhard, Chris Moulding, Peter Shirley - Eurographics Workshop on Rendering , 2001
"... Abstract. Altering the viewing parameters of a 3D object results in computergraphics images of varying quality. One aspect of image quality is the composition of the image. While the esthetic properties of an image are subjective, someheuristics used by artists to create images can be approximated q ..."
Abstract - Cited by 45 (2 self) - Add to MetaCart
Abstract. Altering the viewing parameters of a 3D object results in computergraphics images of varying quality. One aspect of image quality is the composition of the image. While the esthetic properties of an image are subjective, someheuristics used by artists to create images can be approximated quantitatively. We present an algorithm based on heuristic compositional rules for finding the for-mat, viewpoint, and layout for an image of a 3D object. Our system computes viewing parameters automatically or allows a user to explicitly manipulate them.
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Automating camera management in lecture room environments

by Qiong Liu, Yong Rui, Anoop Gupta, Jj Cadiz - Proc. of ACM CHI 2001
"... Given rapid improvements in network infrastructure and streaming-media technologies, a large number of corporations and universities are recording lectures and making them available online for anytime, anywhere access. However, producing high-quality lecture videos is still labor intensive and expen ..."
Abstract - Cited by 44 (7 self) - Add to MetaCart
Given rapid improvements in network infrastructure and streaming-media technologies, a large number of corporations and universities are recording lectures and making them available online for anytime, anywhere access. However, producing high-quality lecture videos is still labor intensive and expensive. Fortunately, recent technology advances are making it feasible to build automated camera management systems to capture lectures. In this paper we report on our design, implementation and study of such a system. Compared to previous work—which has tended to be technology centric— we started with interviews with professional video producers and used their knowledge and expertise to create video production rules. We then targeted technology components that allowed us to implement a substantial portion of these rules, including the design of a virtual video director. The system’s performance was compared to that of a human operator via a user study. Results suggest that our system’s quality is close to that of a human-controlled system. In fact, most remote audience members could not tell if the video was produced by a computer or a person.
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A Camera Engine for Computer Games: Managing the Trade-Off Between Constraint Satisfaction and Frame Coherence

by Nicolas Halper, Ralf Helbing, Thomas Strothotte , 2001
"... 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 w ..."
Abstract - Cited by 43 (2 self) - Add to MetaCart
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.