The light field rendering method is an interesting variation on achieving realism. Once authentic imagery has been acquired using a camera gantry, or a handheld camera, detailed novel views can be synthetically genera...
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The light field rendering method is an interesting variation on achieving realism. Once authentic imagery has been acquired using a camera gantry, or a handheld camera, detailed novel views can be synthetically generated from various viewpoints. One common application of this technique is when a user "walks" through a virtual world. In this situation, only a subset of the previously stored light field is required, and considerable computation burden is encountered in processing the input light field to obtain this subset. In this paper, we show that appropriate portions of the light field can be cached at select "nodal points" that depend on the camera walk. Once spartanly and quickly cached, scenes can be rendered from any point on the walk efficiently. (c) 2006 Elsevier B.V. All rights reserved.
We propose a face recognition method that fuses information acquired from global and local features of the face for improving performance. Principle components analysis followed by Fisher analysis is used for dimensio...
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We propose a face recognition method that fuses information acquired from global and local features of the face for improving performance. Principle components analysis followed by Fisher analysis is used for dimensionality reduction and construction of individual feature spaces. Recognition is done by probabilistically fusing the confidence weights derived from each feature space. The performance of the method is validated on FERET and AR databases. (c) 2006 Elsevier B.V. All rights reserved.
We present a novel eigenspace-based framework to model a dynamic hand gesture that incorporates both hand shape as well as trajectory information. We address the problem of choosing a gesture set that models an upper ...
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We present a novel eigenspace-based framework to model a dynamic hand gesture that incorporates both hand shape as well as trajectory information. We address the problem of choosing a gesture set that models an upper bound on gesture recognition efficiency. We show encouraging experimental results on a such a representative set. (c) 2006 Elsevier B.V. All rights reserved.
We have attempted the problem of novel view synthesis of scenes containing man-made objects from images taken by arbitrary, uncalibrated cameras. Under the assumption of availability of the correspondence of three van...
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We have attempted the problem of novel view synthesis of scenes containing man-made objects from images taken by arbitrary, uncalibrated cameras. Under the assumption of availability of the correspondence of three vanishing points, in general position, we propose two techniques. The first is a transfer-based scheme which synthesizes new views with only a translation of the virtual camera and computes z-buffer values for handling occlusions in synthesized views. The second is a reconstruction-based scheme which synthesizes arbitrary new views in which the camera can undergo rotation as well as translation. We present experimental results to establish the validity of both formulations. (c) 2006 Published by Elsevier B.V.
An intrinsic property of real aperture imaging has been that the observations tend to be defocused. This artifact has been used in an innovative manner by researchers for depth estimation, since the amount of defocus ...
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An intrinsic property of real aperture imaging has been that the observations tend to be defocused. This artifact has been used in an innovative manner by researchers for depth estimation, since the amount of defocus varies with varying depth in the scene. There have been various methods to model the defocus blur. We model the defocus process using the model of diffusion of heat. The diffusion process has been traditionally used in low level vision problems like smoothing, segmentation and edge detection. In this paper a novel application of the diffusion principle is made for generating the defocus space of the scene. The defocus space is the set of all possible observations for a given scene that can be captured using a physical lens system. Using the notion of defocus space we estimate the depth in the scene and also generate the corresponding fully focused equivalent pin-hole image. The algorithm described here also brings out the equivalence of the two modalities, viz. depth from focus and depth from defocus for structure recovery. (c) 2006 Elsevier B.V. All rights reserved.
In content based image retrieval (CBIR) system, search engine retrieves the images similar to the query image according to a similarity measure. It should be fast enough and must have a high precision of retrieval. In...
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In content based image retrieval (CBIR) system, search engine retrieves the images similar to the query image according to a similarity measure. It should be fast enough and must have a high precision of retrieval. Indexing scheme is used to achieve a fast response and relevance feedback helps in improving the retrieval precision. In this paper, a human perception based similarity measure is presented and based on it a simple yet novel indexing scheme with relevance feedback is discussed. The indexing scheme is designed based on the primary and secondary keys which are selected by analysing the entropy of features. A relevance feedback method is proposed based on Mann-Whitney test. The test is used to identify the discriminating features from the relevant and irrelevant images in a retrieved set. Then emphasis of the discriminating features are updated to improve the retrieval performance. The relevance feedback scheme is implemented for two different similarity measure (Euclidean distance based and human perception based). The experiment justifies the effectiveness of the proposed methodologies. Finally, the indexing scheme and relevance feedback mechanism are combined to build up the search engine. (c) 2006 Elsevier B.V. All rights reserved.
Robustness is a key attribute of spread spectrum (SS) watermarking scheme. It is significantly deteriorated if one tries to achieve high embedding rate keeping other parameters unaltered. In literatures, typically var...
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Robustness is a key attribute of spread spectrum (SS) watermarking scheme. It is significantly deteriorated if one tries to achieve high embedding rate keeping other parameters unaltered. In literatures, typically various transformations like DFT, DCT, Fourier-Mellin and wavelet are used for SS multimedia watermarking but little studies have been attempted so far to see what are the possible factors which can improve robustness. The current paper has critically analyzed few such factors namely design of code pattern, proper signal decomposition suitable for data embedding, direction of decomposition, selection of regions for data embedding, signaling scheme, choice of modulation functions and embedding strength. Based on the observation, wavelet based SS watermarking scheme is proposed and improvement in robustness performance is verified through experimental results as well by mathematical analysis. (c) 2006 Elsevier B.V. All rights reserved.
In this paper, the design of a parallel architecture for on-line face recognition using weighted modular principal component analysis (WMPCA) and its system-on-programmable-chip (SoPC) implementation are discussed. Th...
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In this paper, the design of a parallel architecture for on-line face recognition using weighted modular principal component analysis (WMPCA) and its system-on-programmable-chip (SoPC) implementation are discussed. The WMPCA methodology, proposed by us earlier, is based on the assumption that the rates of variation of the different regions of a face are different due to variations in expression and illumination. Given a database of sample faces for training and a query face for recognizing, the WMPCA methodology involves division of the face into horizontal regions. Each of these regions are analyzed independently by computing the eigenfeatures and comparing the same with the corresponding eigenfeatures of the faces stored in the sample database to calculate the corresponding error. The final decision of the face recognizer is based on the weighted sum of the errors computed from each of the regions. These weights are calculated based on the extent to which the various samples of the subject are spread in the eigenspace. The WMPCA methodology has a better recognition rate compared to the modular PCA approach developed by Rajkiran and Vijayan [Rajkiran, G., Vijayan, K., 2004. An improved face recognition technique based on modular PCA approach. Pattern Recognition Letters, 25(4), 429-436]. The methodology also has a wide scope for parallelism. We present an architecture that exploits this parallelism and implement the same as a system-on-programmable-chip on an ALTERA based field programmable gate array (FPGA) platform. The implementation has achieved a processing speed of about 26 frames per second at an operating frequency of 33.33 MHz. (c) 2006 Elsevier B.V. All rights reserved.
In this paper the concept of pixel wise feature extraction for texture segmentation has been extended to block wise feature extraction with the addition of contextual information. A comparative study has been made amo...
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ISBN:
(纸本)9781601320438
In this paper the concept of pixel wise feature extraction for texture segmentation has been extended to block wise feature extraction with the addition of contextual information. A comparative study has been made among different texture feature extraction techniques with this concept. Computational burden is small due to processing in non overlapping blocks. It has been observed that Circular Gabor filter followed by DCT gives the best performance. The results have been validated in presence of noise.
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