{"title":"Reconstructing curved surfaces from specular reflection patterns using spline surface fitting of normals","authors":"Mark A. Halstead, B. Barsky, S. Klein, R. Mandell","doi":"10.1145/237170.237272","DOIUrl":"https://doi.org/10.1145/237170.237272","url":null,"abstract":"Apple Computer, 1 Infinite Loop M/S 301-3J, Cupertino, CA 95014. Computer Science Division, University of California, Berkeley, CA 94720-1776. www.cs.berkeley.edu/projects/optical/ School of Optometry, University of California, Berkeley, CA 94720-2020. We present an algorithm that reconstructs a threedimensional surface model from an image. The image is generated by illuminating a specularly reflective surface with a pattern of light. We discuss the application of this algorithm to an important problem in biomedicine, namely the measurement of the human cornea, although the algorithm is also applicable elsewhere. The distinction between this reconstruction technique and more traditional techniques that use light patterns is that the image is formed by reflection. Therefore, the reconstruction algorithm fits a surface to a set of normals rather than to a set of positions. Furthermore, the normals do not have prescribed surface positions. We show that small surface details can be recovered more accurately using this approach. The results of the algorithm are used in an interactive visualization of the cornea.","PeriodicalId":397587,"journal":{"name":"Proceedings of the 23rd annual conference on Computer graphics and interactive techniques","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115244327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Blue screen matting","authors":"A. R. Smith, J. Blinn","doi":"10.1145/237170.237263","DOIUrl":"https://doi.org/10.1145/237170.237263","url":null,"abstract":"A classical problem of imaging—the matting problem—is separation of a non-rectangular foreground image from a (usually) rectangular background image—for example, in a film frame, extraction of an actor from a background scene to allow substitution of a different background. Of the several attacks on this difficult and persistent problem, we discuss here only the special case of separating a desired foreground image from a background of a constant, or almost constant, backing color. This backing color has often been blue, so the problem, and its solution, have been called blue screen matting. However, other backing colors, such as yellow or (increasingly) green, have also been used, so we often generalize to constant color matting. The mathematics of constant color matting is presented and proven to be unsolvable as generally practiced. This, of course, flies in the face of the fact that the technique is commonly used in film and video, so we demonstrate constraints on the general problem that lead to solutions, or at least significantly prune the search space of solutions. We shall also demonstrate that an algorithmic solution is possible by allowing the foreground object to be shot against two constant backing colors—in fact, against two completely arbitrary backings so long as they differ everywhere.","PeriodicalId":397587,"journal":{"name":"Proceedings of the 23rd annual conference on Computer graphics and interactive techniques","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116339117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Pausch, J. Snoddy, Robert Taylor, Scott Watson, E. Haseltine
{"title":"Disney's Aladdin: first steps toward storytelling in virtual reality","authors":"R. Pausch, J. Snoddy, Robert Taylor, Scott Watson, E. Haseltine","doi":"10.1145/237170.237257","DOIUrl":"https://doi.org/10.1145/237170.237257","url":null,"abstract":"Disney Imagineering has developed a high-fidelity virtual reality (VR) attraction where guests fly a magic carpet through a virtual world based on the animated film “Aladdin.” Unlike most existing work on VR, which has focused on hardware and systems software, we assumed high fidelity and focused on using VR as a new medium to tell stories. We fielded our system at EPCOT Center for a period of fourteen months and conducted controlled experiments, observing the reactions of over 45,000 guests. contact author: Randy Pausch, Computer Science Department, Thornton Hall, University of Virginia, Charlottesville, VA 22903. Pausch@virginia.edu, 804/982-2211 Permission to make digital or hard copies of part or all of this work or personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to st on servers, or to redistribute to lists, requires prior sion and/or a fee. -89791-746-4/96/008...$3.50 193 Riders filled out an exit survey after the experience, and with select groups we used a number of other data-gathering techniques, including interviews and mechanically logging where guests looked and flew. Our major finding is that in a high fidelity VR experience, men and women of all ages suspend disbelief and accept the illusion that they are in a different place. We have found that in VR, as in all media, content matters. Novices are unimpressed with the technology for its own sake; they care about what there is to do in the virtual world. We can improve the experience by telling a pre-immersion “background story” and by giving the guest a concrete goal to perform in the virtual environment. Our eventual goal is to develop the lexicon for this new storytelling medium: the set of communication techniques shared between directors and the audience. We conclude with a discussion of our second version of the Aladdin project, which contains a large number of synthetic characters and a narrative story line. Figure 1: A Guest’s View of the Virtual Environment","PeriodicalId":397587,"journal":{"name":"Proceedings of the 23rd annual conference on Computer graphics and interactive techniques","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121557944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Peter Lindstrom, David Koller, W. Ribarsky, L. Hodges, N. Faust, Gregory A. Turner
{"title":"Real-time, continuous level of detail rendering of height fields","authors":"Peter Lindstrom, David Koller, W. Ribarsky, L. Hodges, N. Faust, Gregory A. Turner","doi":"10.1145/237170.237217","DOIUrl":"https://doi.org/10.1145/237170.237217","url":null,"abstract":"We present an algorithm for real-time level of detail reduction and display of high-complexity polygonal surface data. The algorithm uses a compact and efficient regular grid representation, and employs a variable screen-space threshold to bound the maximum error of the projected image. A coarse level of simplification is performed to select discrete levels of detail for blocks of the surface mesh, followed by further simplification through repolygonalization in which individual mesh vertices are considered for removal. These steps compute and generate the appropriate level of detail dynamically in real-time, minimizing the number of rendered polygons and allowing for smooth changes in resolution across areas of the surface. The algorithm has been implemented for approximating and rendering digital terrain models and other height fields, and consistently performs at interactive frame rates with high image quality.","PeriodicalId":397587,"journal":{"name":"Proceedings of the 23rd annual conference on Computer graphics and interactive techniques","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133883109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Global multi-user virtual environments (panel)","authors":"Wolfgang Felger","doi":"10.1145/237170.237294","DOIUrl":"https://doi.org/10.1145/237170.237294","url":null,"abstract":"The objective of this panel is to discuss the long term development of future large-scale social electronic spaces. In this time and age, this means networked computer systems that exploit the idea of a place inhabited by users who communicate with one another using the natural and informal means appropriate to a range of social situations (e.g. work, family, leisure, etc.). Ideally, such systems should support many thousands of users engaged in real time interaction with one another.","PeriodicalId":397587,"journal":{"name":"Proceedings of the 23rd annual conference on Computer graphics and interactive techniques","volume":"192 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132870479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Cohen, A. Varshney, Dinesh Manocha, Greg Turk, Hans Weber, P. Agarwal, F. Brooks, W. Wright
{"title":"Simplification envelopes","authors":"J. Cohen, A. Varshney, Dinesh Manocha, Greg Turk, Hans Weber, P. Agarwal, F. Brooks, W. Wright","doi":"10.1145/237170.237220","DOIUrl":"https://doi.org/10.1145/237170.237220","url":null,"abstract":"We propose the idea of simplification envelopes for generating a hierarchy of level-of-detail approximations for a given polygonal model. Our approach guarantees that all points of an approximation are within a user-specifiable distance from the original model and that all points of the original model are within a distance from the approximation. Simplificationenvelopes provide a general framework within which a large collection of existing simplification algorithms can run. We demonstrate this technique in conjunction with two algorithms, one local, the other global. The local algorithm provides a fast method for generating approximations to large input meshes (at least hundreds of thousands of triangles). The global algorithm provides the opportunity to avoid local “minima” and possibly achieve better simplifications as a result. Each approximation attempts to minimize the total number of polygons required to satisfy the above constraint. The key advantages of our approach are: General technique providing guaranteed error bounds for genus-preserving simplification Automation of both the simplification process and the selection of appropriate viewing distances Prevention of self-intersection Preservation of sharp features Allows variation of approximation distance across different portions of a model CR","PeriodicalId":397587,"journal":{"name":"Proceedings of the 23rd annual conference on Computer graphics and interactive techniques","volume":"303 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133748436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Issues in networking for entertainment, graphics, and data (panel)","authors":"M. Clinger","doi":"10.1145/237170.237299","DOIUrl":"https://doi.org/10.1145/237170.237299","url":null,"abstract":"only discuss the state-of-the-art in networking graphics, video, audio, voice, and data, but will use the latest technologies to create a virtual panel. An audience at MIT in Boston, MA will be linked via a country wide Asynchronous Transfer Mode (ATM) network to the New Orleans Convention Center to participate \" virtually \" in this panel. Two way video and graphics will be transported over the ATM network to allow for full participation by the remote audience. That same ATM network will extend to Paramount Studios in Los Angeles, CA to allow a panelist to participate \" virtually. \" This panelist will deliver his presentation from LA using an integrated platform to transport high quality graphics over the same infrastructure as the two-way full motion video. During the panel the video-to-ATM equipment will be changed, providing the audience and panelists an opportunity to experience the different technologies. The panelists are from different parts of the industry, but all are using advanced networking techniques and technologies to build the networks that transport multimedia. In addition to delivery of traditional data sets, these networks are built to deliver video, audio, and massive graphics files in real time. One of the networks that will be described was built to allow several auditoriums full of students to observe brain surgery and interact with the surgeon during the surgery. It now delivers traditional data and voice services too. Another network is changing the way a user will look at a network connection. When a studio space is rented to do filming, the production company will rent a network connection providing them connectivity and software services they need while on-site. The computers used can either be rented along with the network, or the customers can bring their own. The latest video-to-ATM devices will be installed at the three locations. Equipment from several different vendors will be used to give the participants an idea of the quality and capabilities of different types of products. All equipment will support 30 frames per second video transported over ATM. Some of the equipment will also support integrated graphics and video support. Panelists will present one of their projects that combines state-of-the-art networking with one or more of the following technologies: • Computer Graphics • Video • Audio • Voice (as in telephony) The presentations will consist of an overview of the business drivers behind the project, the technical details, and …","PeriodicalId":397587,"journal":{"name":"Proceedings of the 23rd annual conference on Computer graphics and interactive techniques","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115719052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A volumetric method for building complex models from range images","authors":"B. Curless, M. Levoy","doi":"10.1145/237170.237269","DOIUrl":"https://doi.org/10.1145/237170.237269","url":null,"abstract":"A number of techniques have been developed for reconstructing surfaces by integrating groups of aligned range images. A desirable set of properties for such algorithms includes: incremental updating, representation of directional uncertainty, the ability to fill gaps in the reconstruction, and robustness in the presence of outliers. Prior algorithms possess subsets of these properties. In this paper, we present a volumetric method for integrating range images that possesses all of these properties. Our volumetric representation consists of a cumulative weighted signed distance function. Working with one range image at a time, we first scan-convert it to a distance function, then combine this with the data already acquired using a simple additive scheme. To achieve space efficiency, we employ a run-length encoding of the volume. To achieve time efficiency, we resample the range image to align with the voxel grid and traverse the range and voxel scanlines synchronously. We generate the final manifold by extracting an isosurface from the volumetric grid. We show that under certain assumptions, this isosurface is optimal in the least squares sense. To fill gaps in the model, we tessellate over the boundaries between regions seen to be empty and regions never observed. Using this method, we are able to integrate a large number of range images (as many as 70) yielding seamless, high-detail models of up to 2.6 million triangles.","PeriodicalId":397587,"journal":{"name":"Proceedings of the 23rd annual conference on Computer graphics and interactive techniques","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125912172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Modeling and rendering of metallic patinas","authors":"Julie Dorsey, P. Hanrahan","doi":"10.1145/237170.237278","DOIUrl":"https://doi.org/10.1145/237170.237278","url":null,"abstract":"An important component that has been missing from image synthesis is the effect of weathering. In this paper, we present an approach for the modeling and rendering of one type of weathering — metallic patinas. A patina is a film or incrustation on a surface that is produced by the removal of material, the addition of material, or the chemical alteration of a surface. Oxidation, sulphidization, and painting are examples of phenomena that produce patinas. We represent a surface as a series of layers. Patinas are simulated with a collection of operators, such as “coat,” “erode,” and “polish,” which are applied to the layered structure. The development of patinas is modulated according to an object’s geometry and local environmental factors. We introduce a technique to model the reflectance and transmission of light through the layered structure using the Kubelka-Munk model. This representation yields a model that can simulate many aspects of the time-dependent appearance of metals as they are exposed to the atmosphere or treated chemically. We demonstrate the approach with a collection of copper models. CR","PeriodicalId":397587,"journal":{"name":"Proceedings of the 23rd annual conference on Computer graphics and interactive techniques","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127898711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Virtual reality and mental disorders (panel)","authors":"Dorothy C. Strickland","doi":"10.1145/237170.237302","DOIUrl":"https://doi.org/10.1145/237170.237302","url":null,"abstract":"treatment for individuals with a variety of mental disorders, including phobias, autism, and Parkinson’s Disease. Panelists will describe their actual case studies and the insights and concerns they discovered in their research. The psychologists and computer scientists on the panel will address the ethical, psychological, and social questions. as well as the technical issues which arise from such applications. They will discuss ideas and suggestions for future directions in using virtual reality with mental disorders, and describe what is needed from the graphics community to refine and extend this work.","PeriodicalId":397587,"journal":{"name":"Proceedings of the 23rd annual conference on Computer graphics and interactive techniques","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123065169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}