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Computationally efficient and reliable fingerprint mosaicking on embedded hardware using minutiae

Machine graphics and Vision 2004年第4期13卷 401-415页

作者： Ramoser, Herbert Birchbauer, Josef Bischof, Horst Advanced Computer Vision GmbH - ACV Donau-City-Strasse 1 1220 Wien Austria Siemens AG Österreich Program and System Engineering Graz Austria Institute for Computer Graphics and Vision Univ. of Technology Graz Austria

Fingerprint matching is a common technique for biometric authentication. Solid state sensors allow the use of fingerprint recognition in small sized embedded systems. The size of these sensors makes it necessary to store several impressions of the same finger to provide good coverage of the entire fingertip. In order to reduce memory requirements and matching time all these impressions can be fused into a single larger image. Memory constraints imposed by embedded computers prohibit the use of images. A fingerprint is therefore represented as a set of minutiae coordinates and minutiae angles. We present a two stage approach to combine two fingerprints. First, a RANSAC based method is used to determine a rigid transformation which roughly aligns the two fingerprints. Second, the transformation is optimised using a robust least median of squares solution. The reliability of the method is demonstrated on a large synthetic dataset and real fingerprint images. The computational complexity and memory requirements allow implementation of the algorithm on embedded hardware.

关键词： Pattern recognition

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Combining and points for interactive high-quality rendering

Combining and points for interactive high-quality rendering

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ACM SIGGRAPH 2003

作者： Bala, Kavita Walter, Bruce Greenberg, Donald P. Computer Science Department Cornell University Program of Computer Graphics Cornell University

This paper presents a new interactive rendering and display technique for complex scenes with expensive shading, such as global illumination. Our approach combines sparsely sampled shading (points) and analytically computed discontinuities (edges) to inter-actively generate high-quality images. The edge-and-point image is a new compact representation that combines edges and points such that fast, table-driven interpolation of pixel shading from nearby point samples is possible, while respecting discontinuities. The edge-and-point renderer is extensible, permitting the use of arbitrary shaders to collect shading samples. Shading discontinuities, such as silhouettes and shadow edges, are found at interactive rates. Our software implementation supports interactive navigation and object manipulation in scenes that include expensive lighting effects (such as global illumination) and geometrically complex objects. For interactive rendering we show that high-quality images of these scenes can be rendered at 8-14 frames per second on a desktop PC: a speedup of 20-60 over a ray tracer computing a single sample per pixel. © 2003 ACM.

关键词： Image analysis

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Functional Difference Predictors (FDPs): Measuring meaningful image differences

Functional Difference Predictors (FDPs): Measuring meaningfu...

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Conference Record of the Thirty-Seventh Asilomar Conference on Signals, Systems and computers

作者： Ferwerda, James A. Pellacini, Fabio Program of Computer Graphics Cornell University Pixar Animation Studios Emeryville CA

In this paper we introduce Functional Difference Predictors (FDPs), a new class of perceptually-based image difference metrics that predict how image errors affect the ability to perform visual tasks using the images. To define the properties of FDPs, we conduct a psychophysical experiment that focuses on two visual tasks: spatial layout and material estimation. In the experiment we introduce errors in the positions and contrasts of objects reflected in glossy surfaces and ask subjects to make layout and material judgments. The results indicate that layout estimation depends only on positional errors in the reflections and material estimation depends only on contrast errors. These results suggest that in many task contexts, large visible image errors may be tolerated without loss in task performance, and that FDPs may be better predictors of the relationship between errors and performance than current Visible Difference Predictors (VDPs).

关键词： computer graphics

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The basic utility vehicle (BUV) - A humanitarian capstone project

The basic utility vehicle (BUV) - A humanitarian capstone pr...

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2003 ASEE Annual Conference and Exposition: Staying in Tune with Engineering Education

作者： Acheson, Douglas C. Computer Graphics Technology Indiana Univ. Purdue U. Indianapolis Computer Graphics Technology Program Purdue Sch. of Eng. and Technology IUPUI

Engineering and technology schools, departments and students are encouraged to explore a capstone design project option that possesses significant, far-reaching implications for international humanitarian application. An Indianapolis, Indiana-based non-profit organization called the "Institute of Affordable Transportation (IAT)" engages young engineering and technology talent through service-based capstone projects to design and develop a class of transportation known as a Basic Utility Vehicle (BUY). The IAT's mission is to improve living standards and enable economic growth in the Third World by creating a simple vehicte that can be assembled almost anywhere, by almost anyone. To propagate this initiative, the IAT hosts an annual collegiate BUY competition that tests student-designed prototype BUV's. Ultimately, the student efforts from these competitions will help provide mobility, freedom and economic hope to people in rural areas of devebping countries. This paper introduces the organization that is the genesis of this initiative, gives an overview of the first two IAT collegiate competitions (including examples of student-designed and other vehicles), reflects on the academic benefits to participating students and faculty and culminates with an invitation to academic institutions to become involved in this life-changing initiative.

关键词： Public utilities

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Combining edges and points for interactive high-quality rendering 03

Combining edges and points for interactive high-quality rend...

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ACM SIGGRAPH 2003 Papers, SIGGRAPH '03

作者： Bala, Kavita Walter, Bruce Greenberg, Donald P. Computer Science Department Cornell University United States Program of Computer Graphics Cornell University United States

ISBN: (纸本)1581137095

This paper presents a new interactive rendering and display technique for complex scenes with expensive shading, such as global illumination. Our approach combines sparsely sampled shading (points) and analytically computed discontinuities (edges) to interactively generate high-quality images. The edge-and-point image is a new compact representation that combines edges and points such that fast, table-driven interpolation of pixel shading from nearby point samples is possible, while respecting *** edge-and-point renderer is extensible, permitting the use of arbitrary shaders to collect shading samples. Shading discontinuities, such as silhouettes and shadow edges, are found at interactive rates. Our software implementation supports interactive navigation and object manipulation in scenes that include expensive lighting effects (such as global illumination) and geometrically complex objects. For interactive rendering we show that high-quality images of these scenes can be rendered at 8 - 14 frames per second on a desktop PC: a speedup of 20 - 60 over a ray tracer computing a single sample per pixel. © 2003 ACM.

关键词： Compressed sensing

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Utilizing the nurbs modeler Rhino® for economical and intuitive 3D product development

Utilizing the nurbs modeler Rhino&reg for economical and int...

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Proceedings: Electrical Insulation Conference and Electrical Manufacturing and Coil Winding Technology

作者： Acheson, Douglas C. Hardin, Jonathan D. Purdue Sch. of Eng. and Technology IUPUI Dept. of Comp. Graphics Technology IUPUI Computer Graphics Technology Program IUPUI

ISBN: (纸本)0941783235

Many manufacturing firms in today's economy are reluctant to engage their design personnel in costly, difficult to operate 3D CAD packages. While the attributes of designing in 3D are numerous and beneficial, committing to a high-end design software package often seems unjustifiable, especially when only a few new designs are required. An extremely attractive alternative to this dilemma is the integration of a powerful and innovative 3D modeling software called Rhinoceros®, or Rhino® for short. While costing substantially less than most 3D modeling programs, Rhino supplies an impressive array of advanced capabilities not found on many of the most powerful design software's on the market. Though not considered a parametric or feature-based modeler, Rhino often supplements these costly packages to accomplish complex surfacing challenges. This paper introduces this incredible program as it applies to the motor manufacturing industry and highlights the ease-of-use and incredible power of this modeling and presentation software. Additionally, an overview of different types of 3D modeling software is given in contextual reference to where this product may fit into a firm's design initiatives.

关键词： Product development

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Functional difference predictors (FDPs): measuring meaningful image differences

Functional difference predictors (FDPs): measuring meaningfu...

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Asilomar Conference on Signals, Systems & computers

作者： J.A. Ferwerda F. Pellacini Program of Computer Graphics Cornell University Pixar Animation Studios Emeryville Emeryville CA USA

In this paper we introduce functional difference predictors (FDPs), a new class of perceptually-based image difference metrics that predict how image errors affect the ability to perform visual tasks using the images. To define the properties of FDPs, we conduct a psychophysical experiment that focuses on two visual tasks: spatial layout and material estimation. In the experiment we introduce errors in the positions and contrasts of objects reflected in glossy surfaces and ask subjects to make layout and material judgments. The results indicate that layout estimation depends only on positional errors in the reflections and material estimation depends only on contrast errors. These results suggest that in many task contexts, large visible image errors may be tolerated without loss in task performance, and that FDPs may be better predictors of the relationship between errors and performance than current visible difference predictors (VDPs).

关键词： Reflection Rendering (computer graphics) computer graphics computer errors Pixel Performance evaluation Conducting materials Performance loss Layout Animation

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Marker-less vision based tracking for mobile augmented reality 03

Marker-less vision based tracking for mobile augmented reali...

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International Symposium on Mixed and Augmented Reality (ISMAR)

作者： D. Beier R. Billert B. Bruderlin D. Stichling B. Kleinjohann Computer Graphics Program Technische Universität Illmenau Ilmenau Germany Intelligent Mobile Systems Universität Paderborn Paderborn Germany

ISBN: (纸本)9780769520063

In this paper an object recognition and tracking approach for the mobile, marker-less and PDA-based augmented reality system AR-PDA is described. For object recognition and localization 2D features are extracted from images and compared with a priori known 3D models. The system consists of a 2D graph matching, 3D hypothesis generation and validation and an additional texture based validation step.

关键词： Augmented reality Cameras Object recognition Feature extraction Mobile computing Layout computer graphics Intelligent systems Production Shape

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Using Perceptual Texture Masking for Efficient Image Synthesis

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computer graphics Forum 2003年第3期21卷

作者： Bruce Walter Sumanta N. Pattanaik Donald P. Greenberg Cornell University † Program of Computer Graphics 580 Rhodes Hall Cornell University Ithaca NY 14853 USA † University of Central Florida SEECS Department of Computer Science Room 250 Orlando FL 32816-2362 USA University of Central Florida

Texture mapping has become indispensable in image synthesis as an inexpensive source of rich visual detail. Less obvious, but just as useful, is its ability to mask image errors due to inaccuracies in geometry or lighting. This ability can be used to substantially accelerate rendering by eliminating computations when the resulting errors will be perceptually insignificant. Our new method precomputes the masking ability of textures using aspects of the JPEG image compression standard. This extra information is stored as threshold elevation factors in the texture's mip-map and interpolated at image generation time as part of the normal texture lookup process. Any algorithm which uses error tolerances or visibility thresholds can then take advantage of texture masking. Applications to adaptive shadow testing, irradiance caching, and path tracing are demonstrated. Unlike prior methods, our approach does not require that initial images be computed before masking can be exploited and incurs only negligible runtime computational overhead. Thus, it is much easier to integrate with existing rendering systems for both static and dynamic scenes and yields computational savings even when only small amounts of texture masking are present. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [computer graphics]: Color, shading, shadowing, and texture

关键词： Visual Perception Perceptual Rendering Texture Mapping JPEG

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Local illumination environments for direct lighting acceleration

Local illumination environments for direct lighting accelera...

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13th Eurographics Workshop on Rendering

作者： Fernandez, Sebastian Bala, Kavita Greenberg, Donald P. Program of Computer Graphics Cornell University Ithaca NY United States

ISBN: (纸本)1581135343

Computing high-quality direct illumination in scenes with many lights is an open area of research. This paper presents a world-space caching mechanism called local illumination environments that enables interactive direct illumination in complex scenes on a cluster of off-the-shelf PCs. A local illumination environment (LIE) caches geometric and radiometric information related to direct illumination. A LIE is associated with every octree cell constructed over the scene. Each LIE stores a set of visible lights, with associated occluders (if they exist). LIEs are effective at accelerating direct illumination because they both eliminate shadow rays for fully visible and fully occluded regions of the scene, and decrease the cost of shadow rays in other regions. Shadow ray computation for the partially occluded regions is accelerated using the cached potential occluders. One important implication of storing occluders is that rendering is accelerated while producing accurate hard and soft shadows. This paper also describes a simple perceptual metric based on Weber's law that further improves the effectiveness of LIEs in the fully visible and partially occluded regions. LIE construction is view-driven, continuously refined, and asynchronous with the shading process. In complex scenes of hundreds of thousands of polygons with up to a hundred lights, the LIEs improve rendering performance by 10x to 30x over a traditional ray tracer.

关键词： Illuminating engineering

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