EuroVisShort2013ISBN 978-3-905673-99-9https://diglib.eg.org:443/handle/10.2312/9892024-03-28T11:17:19Z2024-03-28T11:17:19ZTotal Euler Characteristic as a Noise Measure to aid Transfer Function DesignWiemker, Rafaelhttps://diglib.eg.org:443/handle/10.2312/PE.EuroVisShort.EuroVisShort2013.097-1012022-03-28T06:45:02Z2013-01-01T00:00:00ZTotal Euler Characteristic as a Noise Measure to aid Transfer Function Design
Wiemker, Rafael
Mario Hlawitschka and Tino Weinkauf
For image-based, semi- or fully automated design of transfer functions for direct volume rendering, it is beneficial to have an estimation of the noise level in the rendered image. A topology-motivated noise measure is suggested based on the Euler Characteristic, i.e., on the number of islands and holes in the rendering. The effectiveness of this concept lies in the observation that the Euler Characteristic of the real objects of interest in a rendered scene is usually very low, typically orders of magnitude lower than the Euler Characteristic caused by noise. Interestingly, the Euler Characteristic, which is defined for binary images, can be computed simultaneously for all possible super level sets of an integer-valued gray-scale image in a single raster scan. An efficient algorithm for 2D and 3D is presented with computation cost as low as total variation. The Total Euler Characteristic of the super level sets is proposed as a noise level estimation, i.e., the L1-norm of the evolution curve of the Euler Characteristics for all possible isovalues. The superiority of the Total Euler Characteristic to other common noise estimation methods such as total variation and total second derivatives is demonstrated on renderings of the Marschner-Lobb phantom.
2013-01-01T00:00:00ZMLMD: Multi-Layered Visualization for Multi-Dimensional DataYu, BowenLiu, RichenYuan, Xiaoruhttps://diglib.eg.org:443/handle/10.2312/PE.EuroVisShort.EuroVisShort2013.103-1072022-03-28T06:45:08Z2013-01-01T00:00:00ZMLMD: Multi-Layered Visualization for Multi-Dimensional Data
Yu, Bowen; Liu, Richen; Yuan, Xiaoru
Mario Hlawitschka and Tino Weinkauf
In this paper, we propose and implement a multi-layered visualization technique in 3D space called Multi-Layered Visualization for Multi-Dimensional Data (MLMD) with its corresponding interaction techniques, for visualizing multi-dimensional data. Layers of point based plots are stacked and connected in a virtual visualization cube for comparison between different dimension settings. Viewed from the side, the plot layers intrinsically form parallel coordinates plots. MLMD integrates point based plots and parallel coordinates compactly so as to present more information at a time to help data investigation. Pertinent user interactions for MLMD method to enable convenient manipulation are designed. By using MLMD and its matching interaction techniques, proper dimension settings and in-depth data perception can be achieved.
2013-01-01T00:00:00Z3D Strokes on Visible Structures in Direct Volume RenderingWiebel, AlexanderPreis, PhilippVos, Frans M.Hege, Hans-Christianhttps://diglib.eg.org:443/handle/10.2312/PE.EuroVisShort.EuroVisShort2013.091-0952022-03-28T06:45:04Z2013-01-01T00:00:00Z3D Strokes on Visible Structures in Direct Volume Rendering
Wiebel, Alexander; Preis, Philipp; Vos, Frans M.; Hege, Hans-Christian
Mario Hlawitschka and Tino Weinkauf
In this paper we describe VisiTrace, a novel technique to draw 3D lines in direct volume rendered images. It allows to draw strokes in the 2D space of the screen to produce 3D lines that run on top or in the center of structures visible in the rendering. It is able to ignore structures that shortly occlude the structure that has been visible at the start of the stroke. For this purpose a shortest path algorithm finding the optimal curve in a specially designed graph is employed. We demonstrate the usefulness of the technique by applying it to image data from medicine and engineering, and show how it can be used to mark structures in the example data, and to automatically obtain good views toward these structures enabling faster navigation in the rendering.
2013-01-01T00:00:00ZToward Wall Function Consistent Interpolation of Flow FieldsÜffinger, MarkusSadlo, FilipMunz, Claus-DieterErtl, Thomashttps://diglib.eg.org:443/handle/10.2312/PE.EuroVisShort.EuroVisShort2013.085-0892022-03-28T06:45:05Z2013-01-01T00:00:00ZToward Wall Function Consistent Interpolation of Flow Fields
Üffinger, Markus; Sadlo, Filip; Munz, Claus-Dieter; Ertl, Thomas
Mario Hlawitschka and Tino Weinkauf
In this paper we provide a first step toward simulation-consistent visualization techniques. We focus on wall functions modeling near-wall flow in computational fluid dynamics (CFD) using the law of the wall. By integrating these functions, which are effective only in cells adjacent to solid boundaries, with traditional interpolation schemes used in the interior of the domain, we obtain results that account for the simulation model. We demonstrate the advantages of our scheme using flow visualization techniques on two three-dimensional CFD examples.
2013-01-01T00:00:00Z