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Input Image (input + image)

Distribution by Scientific Domains
Information Science and Computing71%

Selected Abstracts

Multiple path-based approach to image-based street walkthrough

COMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 2 2005
Dong Hoon Lee
Abstract Image-based rendering for walkthrough in the virtual environment has many advantages should over the geometry-based approach, due to the fast construction of the environment and photo-realistic rendered results. In image-based rendering technique, rays from a set of input images are collected and a novel view image is rendered by the resampling of the stored rays. Current such techniques, however, are limited to a closed capture space. In this paper, we propose a multiple path-based capture configuration that can handle a large-scale scene and a disparity-based warping method for novel view generation. To acquire the disparity image, we segment the input image into vertical slit segments using a robust and inexpensive way of detecting vertical depth discontinuity. The depth slit segments, instead of depth pixels, reduce the processing time for novel view generation. We also discuss a dynamic cache strategy that supports real-time walkthroughs in large and complex street environments. The efficiency of the proposed method is demonstrated with several experiments. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Sketching MLS Image Deformations On the GPU

COMPUTER GRAPHICS FORUM, Issue 7 2008
Yanlin Weng
Abstract In this paper, we present an image editing tool that allows the user to deform images using a sketch-based interface. The user simply sketches a set of source curves in the input image, and also some target curves that the source curves should be deformed to. Then the moving least squares (MLS) deformation technique [SMW06] is adapted to produce realistic deformations while satisfying the curves' positional constraints. We also propose a scheme to reduce image fold-overs in MLS deformations. Our system has a very intuitive user interface, generates physically plausible deformations, and can be easily implemented on the GPU for real-time performance. [source]

Hierarchical Context-based Pixel Ordering

COMPUTER GRAPHICS FORUM, Issue 3 2003
Ziv Bar-Joseph
Abstract We present a context-based scanning algorithm which reorders the input image using a hierarchical representationof the image. Our algorithm optimally orders (permutes) the leaves corresponding to the pixels, by minimizing thesum of distances between neighboring pixels. The reordering results in an improved autocorrelation betweennearby pixels which leads to a smoother image. This allows us, for the first time, to improve image compressionrates using context-based scans. The results presented in this paper greatly improve upon previous work in bothcompression rate and running time. Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computer Graphics]: Computational Geometryand Object Modeling I.3.6 [Computer Graphics]: Methodology and Techniques [source]

Exploiting statistical properties of wavelet coefficient for face detection and recognition

PROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2007
Naseer Al-Jawad
Wavelet transforms (WT) are widely accepted as an essential tool for image processing and analysis. Image and video compression, image watermarking, content-base image retrieval, face recognition, texture analysis, and image feature extraction are all but few examples. It provides an alternative tool for short time analysis of quasi-stationary signals, such as speech and image signals, in contrast to the traditional short-time Fourier transform. The Discrete Wavelet Transform (DWT) is a special case of the WT, which provides a compact representation of a signal in the time and frequency domain. In particular, wavelet transforms are capable of representing smooth patterns as well anomalies (e.g. edges and sharp corners) in images. We are focusing here on using wavelet transforms statistical properties for facial feature detection, which allows us to extract the image facial feature/edges easily. Wavelet sub-bands segmentation method been developed and used to clean up the non-significant wavelet coefficients in wavelet sub-band (k) based on the (k-1) sub-band. Moreover, erosion which is considered as one of the fundamental operation in morphological image processing, been used to reduce the unwanted edges in certain directions. For face detection, face template profiles been built for both the face and the eyes for different wavelet sub-band levels to achieve better computational performance, these profiles used to match the extracted profiles from the wavelet domain of the input image using the Dynamic Time Warping technique DTW. The DTW smallest distance allows identifying the face and the eyes location. The performance of face features distances and ratio has been also tested for face verification purposes. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Real-time simulation of watery paint

COMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3-4 2005
Tom Van Laerhoven
Abstract Existing work on applications for thin watery paint is mostly focused on automatic generation of painterly-style images from input images, ignoring the fact that painting is a process that intuitively should be interactive. Efforts to create real-time interactive systems are limited to a single paint medium and results often suffer from a trade-off between real-timeness and simulation complexity. We report on the design of a new system that allows the real-time, interactive creation of images with thin watery paint. We mainly target the simulation of watercolor, but the system is also capable of simulating gouache and Oriental black ink. The motion of paint is governed by both physically based and heuristic rules in a layered canvas design. A final image is rendered by optically composing the layers using the Kubelka,Munk diffuse reflectance model. All algorithms that participate in the dynamics phase and the rendering phase of the simulation are implemented on graphics hardware. Images made with the system contain the typical effects that can be recognized in images produced with real thin paint, like the dark-edge effect, watercolor glazing, wet-on-wet painting and the use of different pigment types. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Multiple path-based approach to image-based street walkthrough

COMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 2 2005
Dong Hoon Lee
Abstract Image-based rendering for walkthrough in the virtual environment has many advantages should over the geometry-based approach, due to the fast construction of the environment and photo-realistic rendered results. In image-based rendering technique, rays from a set of input images are collected and a novel view image is rendered by the resampling of the stored rays. Current such techniques, however, are limited to a closed capture space. In this paper, we propose a multiple path-based capture configuration that can handle a large-scale scene and a disparity-based warping method for novel view generation. To acquire the disparity image, we segment the input image into vertical slit segments using a robust and inexpensive way of detecting vertical depth discontinuity. The depth slit segments, instead of depth pixels, reduce the processing time for novel view generation. We also discuss a dynamic cache strategy that supports real-time walkthroughs in large and complex street environments. The efficiency of the proposed method is demonstrated with several experiments. Copyright © 2005 John Wiley & Sons, Ltd. [source]

A new high-resolution computed tomography (CT) segmentation method for trabecular bone architectural analysis

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2009
Heike Scherf
Abstract In the last decade, high-resolution computed tomography (CT) and microcomputed tomography (micro-CT) have been increasingly used in anthropological studies and as a complement to traditional histological techniques. This is due in large part to the ability of CT techniques to nondestructively extract three-dimensional representations of bone structures. Despite prior studies employing CT techniques, no completely reliable method of bone segmentation has been established. Accurate preprocessing of digital data is crucial for measurement accuracy, especially when subtle structures such as trabecular bone are investigated. The research presented here is a new, reproducible, accurate, and fully automated computerized segmentation method for high-resolution CT datasets of fossil and recent cancellous bone: the Ray Casting Algorithm (RCA). We compare this technique with commonly used methods of image thresholding (i.e., the half-maximum height protocol and the automatic, adaptive iterative thresholding procedure). While the quality of the input images is crucial for conventional image segmentation, the RCA method is robust regarding the signal to noise ratio, beam hardening, ring artifacts, and blurriness. Tests with data of extant and fossil material demonstrate the superior quality of RCA compared with conventional thresholding procedures, and emphasize the need for careful consideration of optimal CT scanning parameters. Am J Phys Anthropol 2009. © 2009 Wiley-Liss, Inc. [source]