The 20 th International Conference in Central Europe on Computer Graphics , Visualization and Computer Vision in co - operation with EUROGRAPHICS W S C G ' 2012

Some of the most brilliant mathematical discoveries of the 1800s were pushed aside for over a century in favor of the vector analysis and linear algebra that we are all familiar with. However, these old ideas have recently been rediscovered in the field of computer graphics by researchers who understand how they can unify many of the geometric operations that are used every day. This talk introduces the basic concepts of the exterior algebra and presents a bigger mathematical picture that enables a deeper understanding of the homogeneous representation of points, lines, and planes, as well as the operations that can be performed among them using the progressive and regressive products. Some emphasis is placed on the history of related mathematics and the past development of incomplete pieces of the bigger picture, such as Plücker coordinates. The goal is to help the audience unlearn some longstanding misnomers in 3D geometry and to provide the knowledge of a larger, unified world into which many familiar mathematical concepts fit together. BRIEF BIOGRAPHY Eric Lengyel is the founder of Terathon Software and the creator of the C4 Engine, a comprehensive technology platform for games and virtual simulations. He holds a Ph.D. in Computer Science from the University of California at Davis and a Masters Degree in Mathematics from Virginia Tech. Eric is the best-selling author of the book Mathematics for 3D Game Programming & Computer Graphics, and he is the series editor for the new Game Engine Gems series. Eric is also a member of the editorial board for the Journal of Graphics Tools, and he is a major contributor to the successful Game Programming Gems series. Eric previously worked in the advanced technology group at Naughty Dog where he developed the driver architecture for the Playstation 3. Prior to that, was the lead programmer for Sierra Studio’s popular adventure game Quest for Glory V, and he worked on OpenGL in Apple’s graphics and imaging department. Overcoming Physical Limitations of Display Devices in Rendering Karol Myszkowski Max-Planck-Institut für Informatik http://www.mpi-inf.mpg.de/ Germany ABSTRACT The knowledge of human visual system (HVS) enables more efficient image rendering by overcoming physical constraints of display devices. This talk presents a number of successful examples of embedding HVS models into real-time rendering pipelines. In particular, I discuss the problem of improving the appearance of highlights and light sources by boosting their apparent brightness using the temporal glare technique. Also, I discuss how to overcome physical contrast limitations of display devices by using the 3D unsharp masking technique to boost the apparent contrast. Also, I present techniques for apparent resolution enhancement, which enable showing image details beyond the physical pixel resolution of the display device. Finally, I discuss the role of perception in context of stereovision and accommodation/vergence conflict reduction BRIEF BIOGRAPHY Karol Myszkowski is a tenured senior researcher at the MPI Informatik, Saarbruecken, Germany. In the period from 1993 till 2000 he served as an associate professor in the Department of Computer Software at the University of Aizu, Japan. In the period from 1986 till 1992 he worked for Integra, Inc. a Japanbased, company specialized in developing rendering and global illumination software. He received his PhD (1991) and habilitation (2001) degrees in computer science from Warsaw University of Technology (Poland). In 2011 he was awarded with a lifetime professor title by the President of Poland. His research interests include perception issues in graphics, high dynamic range imaging, global illumination and rendering. Karol published and lectured on these topics widely including ACM Siggraph/Siggraph Asia Courses in 2001, 2002, 2004, 2006, and 2012. He also co-chaired Rendering Symposium in 2001, ACM Symposium on Applied Perception in Graphics and Visualization in 2008, Spring Conference on Computer Graphics 2008, and Graphicon 2012The knowledge of human visual system (HVS) enables more efficient image rendering by overcoming physical constraints of display devices. This talk presents a number of successful examples of embedding HVS models into real-time rendering pipelines. In particular, I discuss the problem of improving the appearance of highlights and light sources by boosting their apparent brightness using the temporal glare technique. Also, I discuss how to overcome physical contrast limitations of display devices by using the 3D unsharp masking technique to boost the apparent contrast. Also, I present techniques for apparent resolution enhancement, which enable showing image details beyond the physical pixel resolution of the display device. Finally, I discuss the role of perception in context of stereovision and accommodation/vergence conflict reduction BRIEF BIOGRAPHY Karol Myszkowski is a tenured senior researcher at the MPI Informatik, Saarbruecken, Germany. In the period from 1993 till 2000 he served as an associate professor in the Department of Computer Software at the University of Aizu, Japan. In the period from 1986 till 1992 he worked for Integra, Inc. a Japanbased, company specialized in developing rendering and global illumination software. He received his PhD (1991) and habilitation (2001) degrees in computer science from Warsaw University of Technology (Poland). In 2011 he was awarded with a lifetime professor title by the President of Poland. His research interests include perception issues in graphics, high dynamic range imaging, global illumination and rendering. Karol published and lectured on these topics widely including ACM Siggraph/Siggraph Asia Courses in 2001, 2002, 2004, 2006, and 2012. He also co-chaired Rendering Symposium in 2001, ACM Symposium on Applied Perception in Graphics and Visualization in 2008, Spring Conference on Computer Graphics 2008, and Graphicon 2012 Physically Based Weathering Simulation of Natural Objects Based on Biological Analysis Enhua Wu State Key Lab. of Computer Science, Chinese Academy of Sciences, Beijing & University of Macau, Macao,China ABSTRACT The Weathering effect of nature objects or natural scenes is a common phenomenon in our daily life. However, little investigation has been made to the phenomenon so far in computer graphics field. The weathering procedure on the nature objects such as plants, trees, grasses etc. is a slowly changing process, and in fact it is involved with a comprehensive drying procedure made towards the biological structure of the nature objects, in terms of the shape change of the objects & the color change of their appearance. With regard to the shape change or deformation, a physically based mechanical calculation is applied to the biological components incurred by the drying effect in our solution. On the other hand, the change of color appearance could be simulated based on the synthesis to the color spectrum of the samples collected in the weathering process of the objects. The simulation based the scheme will be demonstrated by the simulation result to the trees, grassland, fruits etc. BRIEF BIOGRAPHY Dr. Enhua Wu completed his BSc in Tsinghua University, Beijing in 1970 and received his Ph.D degree from Dept. of Computer Science, University of Manchester, England in 1984. Since 1985 he has been working at the Institute of Software, Chinese Academy of Sciences, as a director of the Research Dept. of Fundamental Theory and Advanced Technology until 1998. Since September of 1997, he has been also invited as a full professor of University of Macau (UM). Dr. Wu’s main interests are Realistic Image Synthesis, Virtual Reality and Scientific Visualization. Now he is an Associate Editor-inChief of the Journal of Computer Science and Technology (Science Press and Springer) and the editorial board member of TVC, CAVW, IJIG, IJVR, IJSI. He has been also in recent years invited as a keynote speaker or chairing works in a number of international conferences such as ACM VRST2010, CASA2011, ACM VRCAI2008-2012, IEEE VR2011-12 etc.The Weathering effect of nature objects or natural scenes is a common phenomenon in our daily life. However, little investigation has been made to the phenomenon so far in computer graphics field. The weathering procedure on the nature objects such as plants, trees, grasses etc. is a slowly changing process, and in fact it is involved with a comprehensive drying procedure made towards the biological structure of the nature objects, in terms of the shape change of the objects & the color change of their appearance. With regard to the shape change or deformation, a physically based mechanical calculation is applied to the biological components incurred by the drying effect in our solution. On the other hand, the change of color appearance could be simulated based on the synthesis to the color spectrum of the samples collected in the weathering process of the objects. The simulation based the scheme will be demonstrated by the simulation result to the trees, grassland, fruits etc. BRIEF BIOGRAPHY Dr. Enhua Wu completed his BSc in Tsinghua University, Beijing in 1970 and received his Ph.D degree from Dept. of Computer Science, University of Manchester, England in 1984. Since 1985 he has been working at the Institute of Software, Chinese Academy of Sciences, as a director of the Research Dept. of Fundamental Theory and Advanced Technology until 1998. Since September of 1997, he has been also invited as a full professor of University of Macau (UM). Dr. Wu’s main interests are Realistic Image Synthesis, Virtual Reality and Scientific Visualization. Now he is an Associate Editor-inChief of the Journal of Computer Science and Technology (Science Press and Springer) and the editorial board member of TVC, CAVW, IJIG, IJVR, IJSI. He has been also in recent years invited as a keynote speaker or chairing works in a number of international conferences such as ACM VRST2010, CASA2011, ACM VRCAI2008-2012, IEEE VR2011-12 etc. A Beginners Guide to Dual-Quaternions What They Are, How They Work, and How to Use Them for 3D Character Hierarchies Ben Kenwright School of Computing Science, Newcastle University Newcastle Upon Tyne, United Kingdom [email protected] ABSTRACT In this paper, we give a beginners guide to the practicality of using dual-quaternions to represent the rotations and translations in character-based hierarchies. Quaternions have proven themselves in many fields of science and computing as providing an unambiguous, un-cumbersome, computationally efficient method of representing rotational information. We hope after reading this paper the reader will take a similar view on dual-quaternions. We explain how dual number theory can extend quaternions to dual-quaternions and how we can use them to represent rigid transforms (i.e., translations and rotations). Through a set of examples, we demonstrate exactly how dual-quaternions relate rotations and translations and compare them with traditional Euler’s angles in combination with Matrix concatenation. We give a clear-cut, step-by-step introduction to dual-quaternions, which is followed by a no-nonsense how-to approach on employing them in code. The reader, I believe, after reading this paper should be able to see how dual-quaternions can offer a straightforward solution of representing rigid transforms (e.g., in complex character hierarchies). We show how dual-quaternions propose a novel alternative to pure Euler-Matrix methods and how a hybrid system in combination with matrices results in a faster more reliable solution. We focus on demonstrating the enormous rewards of using dual-quaternions for rigid transforms and in particular their application in complex 3D character hierarchies.In this paper, we give a beginners guide to the practicality of using dual-quaternions to represent the rotations and translations in character-based hierarchies. Quaternions have proven themselves in many fields of science and computing as providing an unambiguous, un-cumbersome, computationally efficient method of representing rotational information. We hope after reading this paper the reader will take a similar view on dual-quaternions. We explain how dual number theory can extend quaternions to dual-quaternions and how we can use them to represent rigid transforms (i.e., translations and rotations). Through a set of examples, we demonstrate exactly how dual-quaternions relate rotations and translations and compare them with traditional Euler’s angles in combination with Matrix concatenation. We give a clear-cut, step-by-step introduction to dual-quaternions, which is followed by a no-nonsense how-to approach on employing them in code. The reader, I believe, after reading this paper should be able to see how dual-quaternions can offer a straightforward solution of representing rigid transforms (e.g., in complex character hierarchies). We show how dual-quaternions propose a novel alternative to pure Euler-Matrix methods and how a hybrid system in combination with matrices results in a faster more reliable solution. We focus on demonstrating the enormous rewards of using dual-quaternions for rigid transforms and in particular their application in complex 3D character hierarchies.