@article{arikan-2015-dmrt, title = "Multi-Depth-Map Raytracing for Efficient Large-Scene Reconstruction", author = "Murat Arikan and Reinhold Preiner and Michael Wimmer", year = "2016", abstract = "With the enormous advances of the acquisition technology over the last years, fast processing and high-quality visualization of large point clouds have gained increasing attention. Commonly, a mesh surface is reconstructed from the point cloud and a high-resolution texture is generated over the mesh from the images taken at the site to represent surface materials. However, this global reconstruction and texturing approach becomes impractical with increasing data sizes. Recently, due to its potential for scalability and extensibility, a method for texturing a set of depth maps in a preprocessing and stitching them at runtime has been proposed to represent large scenes. However, the rendering performance of this method is strongly dependent on the number of depth maps and their resolution. Moreover, for the proposed scene representation, every single depth map has to be textured by the images, which in practice heavily increases processing costs. In this paper, we present a novel method to break these dependencies by introducing an efficient raytracing of multiple depth maps. In a preprocessing phase, we first generate high-resolution textured depth maps by rendering the input points from image cameras and then perform a graph-cut based optimization to assign a small subset of these points to the images. At runtime, we use the resulting point-to-image assignments (1) to identify for each view ray which depth map contains the closest ray-surface intersection and (2) to efficiently compute this intersection point. The resulting algorithm accelerates both the texturing and the rendering of the depth maps by an order of magnitude.", month = feb, doi = "10.1109/TVCG.2015.2430333", issn = "1077-2626", journal = "IEEE Transactions on Visualization & Computer Graphics", number = "2", volume = "22", pages = "1127--1137", URL = "https://www.cg.tuwien.ac.at/research/publications/2016/arikan-2015-dmrt/", } @article{arikan-2014-pcvis, title = "Large-Scale Point-Cloud Visualization through Localized Textured Surface Reconstruction", author = "Murat Arikan and Reinhold Preiner and Claus Scheiblauer and Stefan Jeschke and Michael Wimmer", year = "2014", abstract = "In this paper, we introduce a novel scene representation for the visualization of large-scale point clouds accompanied by a set of high-resolution photographs. Many real-world applications deal with very densely sampled point-cloud data, which are augmented with photographs that often reveal lighting variations and inaccuracies in registration. Consequently, the high-quality representation of the captured data, i.e., both point clouds and photographs together, is a challenging and time-consuming task. We propose a two-phase approach, in which the first (preprocessing) phase generates multiple overlapping surface patches and handles the problem of seamless texture generation locally for each patch. The second phase stitches these patches at render-time to produce a high-quality visualization of the data. As a result of the proposed localization of the global texturing problem, our algorithm is more than an order of magnitude faster than equivalent mesh-based texturing techniques. Furthermore, since our preprocessing phase requires only a minor fraction of the whole dataset at once, we provide maximum flexibility when dealing with growing datasets.", month = sep, issn = "1077-2626", journal = "IEEE Transactions on Visualization & Computer Graphics", number = "9", volume = "20", pages = "1280--1292", keywords = "image-based rendering, large-scale models, color, surface representation", URL = "https://www.cg.tuwien.ac.at/research/publications/2014/arikan-2014-pcvis/", } @article{preiner2014clop, title = "Continuous Projection for Fast L1 Reconstruction", author = "Reinhold Preiner and Oliver Mattausch and Murat Arikan and Renato Pajarola and Michael Wimmer", year = "2014", abstract = "With better and faster acquisition devices comes a demand for fast robust reconstruction algorithms, but no L1-based technique has been fast enough for online use so far. In this paper, we present a novel continuous formulation of the weighted locally optimal projection (WLOP) operator based on a Gaussian mixture describing the input point density. Our method is up to 7 times faster than an optimized GPU implementation of WLOP, and achieves interactive frame rates for moderately sized point clouds. We give a comprehensive quality analysis showing that our continuous operator achieves a generally higher reconstruction quality than its discrete counterpart. Additionally, we show how to apply our continuous formulation to spherical mixtures of normal directions, to also achieve a fast robust normal reconstruction. Project Page: https://www.cg.tuwien.ac.at/~preiner/projects/clop/", month = aug, journal = "ACM Transactions on Graphics (Proc. of ACM SIGGRAPH 2014)", volume = "33", number = "4", issn = "0730-0301", doi = "10.1145/2601097.2601172", pages = "47:1--47:13", keywords = "point set, Gaussian mixture, Hierarchical EM, upsampling, dynamic reconstruction, L1 reconstruction", URL = "https://www.cg.tuwien.ac.at/research/publications/2014/preiner2014clop/", } @inproceedings{birsak-2013-sta, title = "Seamless Texturing of Archaeological Data", author = "Michael Birsak and Przemyslaw Musialski and Murat Arikan and Michael Wimmer", year = "2013", abstract = "In this paper we propose a framework for out-of-core real-time rendering of high-quality textured archaeological data-sets. Our input is a triangle mesh and a set of calibrated and registered photographs. Our system performs the actual mapping of the photos to the mesh for high-quality reconstructions, which is a task referred to as the labeling problem. Another problem of such mappings are seams that arise on junctions between triangles that contain information from different photos. These are are approached with blending methods, referred to as leveling. We address both problems and introduce a novel labeling approach based on occlusion detection using depth maps that prevents texturing of parts of the model with images that do not contain the expected region. Moreover, we propose an improved approach for seam-leveling that penalizes too large values and helps to keep the resulting colors in a valid range. For high-performance visualization of the 3D models with a huge amount of textures, we make use of virtual texturing, and present an application that generates the needed texture atlas in significantly less time than existing scripts. Finally, we show how the mentioned components are integrated into a visualization application for digitized archaeological site.", month = oct, isbn = "978-1-4799-3168-2 ", publisher = "IEEE", note = "DOI: 10.1109/DigitalHeritage.2013.6743749", location = "Marseille, France", booktitle = "Digital Heritage International Congress (DigitalHeritage), 2013", pages = "265--272 ", keywords = "digital cultural heritage, out-of-core real-time rendering, seamless texturing, virtual texturing", URL = "https://www.cg.tuwien.ac.at/research/publications/2013/birsak-2013-sta/", } @article{arikan-2013-osn, title = "O-Snap: Optimization-Based Snapping for Modeling Architecture", author = "Murat Arikan and Michael Schw\"{a}rzler and Simon Fl\"{o}ry and Michael Wimmer and Stefan Maierhofer", year = "2013", abstract = "In this paper, we introduce a novel reconstruction and modeling pipeline to create polygonal models from unstructured point clouds. We propose an automatic polygonal reconstruction that can then be interactively refined by the user. An initial model is automatically created by extracting a set of RANSAC-based locally fitted planar primitives along with their boundary polygons, and then searching for local adjacency relations among parts of the polygons. The extracted set of adjacency relations is enforced to snap polygon elements together, while simultaneously fitting to the input point cloud and ensuring the planarity of the polygons. This optimization-based snapping algorithm may also be interleaved with user interaction. This allows the user to sketch modifications with coarse and loose 2D strokes, as the exact alignment of the polygons is automatically performed by the snapping. The generated models are coarse, offer simple editing possibilities by design and are suitable for interactive 3D applications like games, virtual environments etc. The main innovation in our approach lies in the tight coupling between interactive input and automatic optimization, as well as in an algorithm that robustly discovers the set of adjacency relations.", month = jan, journal = "ACM Transactions on Graphics", volume = "32", number = "1", issn = "0730-0301", doi = "10.1145/2421636.2421642", pages = "6:1--6:15", keywords = "interactive modeling, surface reconstruction, geometric optimization", URL = "https://www.cg.tuwien.ac.at/research/publications/2013/arikan-2013-osn/", } @archiveproject{arikan-thesis, title = "(unknown)", author = "Murat Arikan", year = "2022", URL = "https://www.cg.tuwien.ac.at/research/publications/2022/arikan-thesis/", }