• News

    :: 2015 CGLab got funding for a TUBITAK research grant on Data Analytics

    :: 2012 CGLab got funding for a bilateral research grant on Augmented Reality together with Università di Bologna.

    :: 2011 CGLab got funding for two Turk Telekom research grants on Augmented Reality.

    :: 2010 Research results will be presented at ISCIS (UK) Conference.

    :: 2010 CGLab got funding for a TUBITAK research grant on Information Visualization

    :: 2010 CGLab member Selcuk Sumengen got TUBITAK fellowship to collaborate with UC Merced.

    :: 2009 Research results will be presented at CGI (Canada), CASA (NL), HCI (USA) and GeoVis (D) Conferences.

    :: 2008 research results were presented at SIGGRAPH, Information Visualization VRCAI, Cyberworlds and CAA 2008 Conferences.

    :: Istanbul Archaeology Museum Marmaray-Metro Rescue Excavations Symposium (in Turkish)

    :: CGLab members received IBM Faculty Award

    :: CGI 2008 will be in Istanbul and co-organized by CG Lab

    :: Three CS 450 'Computing and Art' course projects will be presented at SIGGRAPH'07 and IEEE InfoVis'07 as poster presentations

    :: CG Lab got awarded with a collaboration project on Medical VR and AR with University of Lecce, Italy

    :: A toolkit for cultural heritage researchers,CH-Tools is freely available

    :: Recent papers will be presented at CGI 2007, HCI 2007, Grapp 2007 and CAA 2007

    :: CG Lab got awarded with Sabanci University internal grant for a transdiciplinary project 'Novel Representation and interaction techniques of complex datasets'

    :: CG Lab participated to the exhibition of Techne digital performance platform between 17-22 April, 2006.

    :: CG Lab got funding for three TUBITAK research projects

Representational image generation for 3D objects

Ekrem Serin, Selcuk Sumengen, Selim Balcisoy
meshFinding good representational images for 3D object exploration is a highly subjective problem in the cognitive field. The “best” or “good” definitions do not depend on any metric. We have explained the VKL distance concept and introduced a novel view descriptor called vSKL distance for finding “good” representational images. The image generation is done by projecting the surfaces of 3D objects onto the screen or any planar surface. The projection process depends on parameters such as camera position, camera vector, up vector, and clipping plane positions. In this work we present a technique to find such camera positions that the 3D object is projected in “good” or “best” way where those subjective definitions are mapped to Information Theoretical distances. We compared greedy view selection integrated vSKL with two well known techniques: VKL and VMI. vSKL performs very close to the other two, hence face coverage perturbation is minimal, but it is 3 to 4 times faster. Furthermore, the saliency information is conveyed to users with generated images.
The Visual Computer 29(6-8): 675-684 (2013) doi: 10.1007/s00371-013-0805-5

Real-time feature-based image morphing for memory-efficient impostor rendering and animation on GPU

Kamer Ali Yüksel, Alp Yucebilgin, Selim Balcisoy, Aytül Erçil
Real-time rendering of large animated crowds consisting of thousands of virtual humans is important for several applications including simulations, games, and interactive walkthroughs but cannot be performed using complex polygonal models at interactive frame rates. For that reason, methods using large numbers of precomputed image-based representations, called impostors, have been proposed. These methods take advantage of existing programmable graphics hardware to compensate for computational expense while maintaining visual fidelity. Thanks to these methods, the number of different virtual humans rendered in real time is no longer restricted by computational power but by texture memory consumed for the variety and discretization of their animations. This work proposes a resource-efficient impostor rendering methodology that employs image morphing techniques to reduce memory consumption while preserving perceptual quality, thus allowing higher diversity or resolution of the rendered crowds. Results of the experiments indicated that the proposed method, in comparison with conventional impostor rendering techniques, can obtain 38 % smoother animations or 87 % better appearance quality by reducing the number of key-frames required for preserving the animation quality via resynthesizing them with up to 92 % similarity on real time.
The Visual Computer 29(2): 131-140 (2013) doi:10.1007/s00371-012-0718-8

Simulating colliding flows in smoothed particle hydrodynamics with fractional derivatives

Oktar Ozgen, Selcuk Sumengen, Marcelo Kallmann, Carlos F. M. Coimbra, Selim Balcisoy


We propose a new method based on the use of fractional differentiation for improving the efficiency and realism of simulations based on smoothed particle hydrodynamics (SPH). SPH represents a popular particle-based approach for fluid simulation and a high number of particles is typically needed for achieving high quality results. However, as the number of simulated particles increase, the speed of computation degrades accordingly. The proposed method employs fractional differentiation to improve the results obtained with SPH in a given resolution. The approach is based on the observation that effects requiring a high number of particles are most often produced from colliding flows, and therefore, when the modeling of this behavior is improved, higher quality results can be achieved without changing the number of particles being simulated. Our method can be employed to reduce the resolution without significant loss of quality, or to improve the quality of the simulation in the current chosen resolution. The advantages of our method are demonstrated with several quantitative evaluations.
Comp. Anim. Virtual Worlds, 24: 511–523. doi: 10.1002/cav.1527

CGLab is co-hosting CASA 2013, Istanbul

Bilkent University, Sabanci University, Microsoft Turkey and Computer Graphics Society (CGS) are pleased to announce the 26th International Conference on Computer Animation and Social Agents (CASA 2013) to be held on May 16-18, 2013 in Istanbul, Turkey. http://www.cs.bilkent.edu.tr/~casa2013/

Congratulations !

Dr. Ekrem Serin defended his PhD thesis on INFORMATION THEORY ASSISTED DATA VISUALIZATION AND EXPLORATION successfully.

First year Undergrad Student Project (Proj102)

Sabancı Üniversitesi LAYAR Layer. Watch the video

Spring 2012, CS450 Arts and Computing

Another Spring Term will start with CS450 Arts and Computing class. Together with Elif Ayıter and Murat Germen we are teaching this class with great joy over five years. Visit the blog for more information.