Real-Time Image Abstraction by Directed Filtering

February 24, 2009 – 2:23 pm

shaderx7Kyprianidis, J. E. & Döllner, J. (2009). Real-Time Image Abstraction by Directed Filtering. In W. Engel (Ed.), ShaderX7 – Advanced Rendering Techniques. Charles River Media.

In this chapter we present a framework of automatic image processing techniques that create high-quality, simplified, stylistic illustrations from color images, videos, and 3D renderings. Our method extends the approach of Winnemöller et al. (2006) to use iterated bilateral filtering for abstraction and difference-of-Gaussians (DoG) for edge detection. We present enhancements to these techniques to improve the quality of the output by adapting them to the local orientation of the input. Read More »

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Approaches to Image Abstraction for Photorealistic Depictions of Virtual 3D Models

February 16, 2009 – 9:00 am

megacity_nprDöllner, J. & Kyprianidis, J. E. (2009). Approaches to image abstraction for photorealistic depictions of virtual 3d models. In Proc. ICA Symposium on Cartography for Central and Eastern Europe.

In our contribution, we present approaches of automatic image abstraction, applied to images and image sequences derived as views of virtual 3D city models and landscape models. We first discuss the requirements of cartography-specific visualization based on the virtual globe metaphor as well as the specific characteristics and deficiencies of visualization based on photorealism. We introduce a concept that extends the classical visualization pipeline by cartography-specific functionality, object-space and image-space abstraction, which also represent the two principle ways for implementing cartographic visualization systems. Abstraction provides the prerequisites to visually communicate uncertainty, to simplify and filter detailed elements, and to clearly encode displayed information of complex geospatial information. In addition, it offers many degrees of freedoms for artistic and stylistic design of cartographic products. Furthermore, we outline general working principles and implementation of an automatic image-space abstraction technique we developed that creates high-quality, simplified, stylistic illustrations from color images, videos, and 3D renderings. Read More »

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Techniques for the Interactive Exploration of High-Detail 3D Building Reconstruction Using the Example of Roman Cologne

October 20, 2008 – 9:00 am

Maass, S., Trapp, M., Kyprianidis, J. E., Döllner, J., Eichhorn, M., Pokorski, R., Bäuerlein, J., & Hesberg, H. v. (2008). Techniques for the Interactive Exploration of High-Detail 3D Building Reconstruction Using the Example of Roman Cologne. In M. Ioannides, A. Addison, A. Georgopoulos, & L. Kalisperis (Eds.), Proceedings of 14th International Conference on Virtual Systems and Multimedia (VSMM 2008) (pp. 223–229).: Archaeolingua.

This paper presents the results achieved by an interdisciplinary team of archaeologists, designers, and computer graphics engineers with the aim to virtually reconstruct an interactive high-detail 3D city model of Roman Cologne. We describe a content creation pipeline established to enable a flexible exchange and enhancement of building models, the applied optimization techniques necessary for real-time rendering, and the design of an application framework that enables the coupling of 3D visualizations with additional information in corresponding Adobe® Flash® widgets. Furthermore, we expose challenges arising by incorporating state-of-the-art visualization techniques, such as cut-away views, non-photorealistic rendering (NPR), and automated label placement. These techniques are used to enhance the interactive 3D environments, to enable for the presentation of interior structures, the precise communication what is hypothetic and what proven knowledge, and the integration of meta information. Read More »

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Mechanisms on Graphical Core Variables in the Design of Cartographic 3D City Presentations

July 24, 2008 – 9:00 am

jobst-2008Jobst, M., Kyprianidis, J. E., & Döllner, J. (2008). Mechanisms on Graphical Core Variables in the Design of Cartographic 3D City Presentations. In I. Moore, Antoni; Drecki (Ed.), Geospatial Vision, Lecture Notes in Geoinformation and Cartography (pp. 45–59).: Springer.

Virtual 3D city models are increasingly used in geospatial planning and discussion processes. This is one reason that the effectiveness and expressiveness of the presentation form has to be investigated from a cartographic point of view. This investigation reaches from recording and modelling procedures for 3D city models to a semiotic model, which has to be adapted for the use of 3D. This contribution focuses on mechanisms on graphical core variables that play an important role for the precise geospatial information transmission with 3D. Methods of non-photorealistic rendering can be combined with cartographic requirements. By this means a new potential for the graphic design of cartographic 3D city presentations can be shown. Read More »

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Image Abstraction by Structure Adaptive Filtering

June 9, 2008 – 9:00 am

jkypiran-2008-tpcg-overviewKyprianidis, J. E. and Döllner, J. (2008). Image abstraction by structure adaptive filtering. In Proc. EG UK Theory and Practice of Computer Graphics, pp. 51-58.

In this work we present a framework of automatic non-photorealistic image processing techniques that create simplified stylistic illustrations from color images, videos and 3D renderings. To smooth low-contrast regions while preserving edges, we present a new fast separated implementation of the bilateral filter. Our approach works by filtering in direction of the gradient and then filtering the intermediate result in perpendicular direction. When applied iteratively, our approach does not suffer from horizontal or vertical artifacts and creates smooth output at curved boundaries. To extract salient important edges we first apply a one-dimensional difference-of-Gaussians filter in direction of the gradient and then apply smoothing along a flow field which we derive from the smoothed structure tensor. Our method creates smooth coherent output for line and curve segments. Read More »

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AcroOpenEx: pdfTeX edit/run/preview made easy

May 14, 2008 – 9:00 am

It annoyed me for years that a nice edit->run->preview cycle with pdfTeX and Adobe Acrobat isn’t possible. It annoyed me so much that I downloaded the Acrobat SDK and hacked a small plugin. The plugin opens the PDF file, creates a new document in memory, copies all pages from the file to the new document and then closes the file. Read More »

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