The amount of digitized video in video archives is becoming so huge that easier access and content browsing tools are desperately needed. Also, video is no longer one big piece of data but a collection of useful small...
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ISBN:
(纸本)0819431273
The amount of digitized video in video archives is becoming so huge that easier access and content browsing tools are desperately needed. Also, video is no longer one big piece of data but a collection of useful smaller building blocks that can be accessed and used independently from the original context of presentation. In this paper, we demonstrate a content model for audio-video sequences with the purpose of enabling the automatic generation of video summaries. The model is based on descriptors which indicate various properties and relations of audio and video segments. In practice, these descriptors could either be generated automatically by analysis methods, or produced manually (or computer-assisted) by the content provider himself. We analyze the requirements and characteristics of the different data segments with respect to the problem of summarization, and we define our model as a set of constraints which allow to produce good quality summaries.
databases are increasingly being used to store multimedia objects such as maps, images, audio, and video. storage and retrieval of these objects is accomplished using multidimensional index structures such as R*-trees...
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databases are increasingly being used to store multimedia objects such as maps, images, audio, and video. storage and retrieval of these objects is accomplished using multidimensional index structures such as R*-trees and SS-trees. As dimensionality increases, query performance in these index structures degrades. This phenomenon, generally referred to as the dimensionality curse, can be circumvented by reducing the dimensionality of the data. Such a reduction is, however, accompanied by a loss of precision of query results. Current techniques such as QBIC use SVD transform-based dimensionality reduction to ensure high query precision. The drawback of this approach is that SVD is expensive to compute and, therefore, not readily applicable to dynamic databases. In this paper, we propose novel techniques for performing SVD-based dimensionality reduction in dynamic databases. When the data distribution changes considerably so as to degrade query precision, we recompute the SVD transform and incorporate it in the existing index structure. For recomputing the SVD-transform, we propose a novel technique that uses aggregate data from the existing index rather than the entire data. This technique reduces the SVD-computation time without compromising query precision. We then explore efficient ways to incorporate the recomputed SVD-transform in the existing index structure. These techniques reduce the computation time by a factor of 20 in experiments on color and texture image vectors. The error due to approximate computation of SVD is less than 10%. (C) 1999 Academic Press.
In this paper, we propose a new image feature extraction method for MPEG compressed video. To minimize the MPEG decoding process, we use only DC values for Y, Cr, and Cb components for each macroblock. Then, we can ob...
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In this paper, we propose a new image feature extraction method for MPEG compressed video. To minimize the MPEG decoding process, we use only DC values for Y, Cr, and Cb components for each macroblock. Then, we can obtain a feature vector using the decoded DC values of Y, Cr, and Cb components for all macroblocks in an I frame. The feature vector consists of histograms for various colors, luminance, and edge types. In obtaining histograms for colors and luminance features, we consider the ratio of contributing pure colors and luminance to the chroma DC values for each macroblock. Then, we update all contributing colors and/or luminance histograms accordingly. Otherwise, if the macro block is classified as an edge block, then we update the corresponding edge type histogram. To demonstrate the performance of the proposed feature extraction method, we apply it to a scene change detection problem.
We have developed a wide-area-distributed storage system for multimedia databases that minimizes the possibility of simultaneous failure of multiple disks in the event of a major disaster. It features a RAID system wh...
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We have developed a wide-area-distributed storage system for multimedia databases that minimizes the possibility of simultaneous failure of multiple disks in the event of a major disaster. It features a RAID system whose member disks are spatially distributed over a wide area. Each node has a device that includes the controller of the RAID and the controller of the member disks controlled by other nodes. The devices in the node are connected to a computer using fiber optic cables and communicate using Fibre-Channel technology. Any computer at a node can utilize multiple devices connected by optical fibers as a single 'virtual disk'. The advantage of this system structure is that devices and fiber optic cables are shared by the computers. In this report, we first describe our proposed system and a prototype we used for testing. Then we discuss its performance, i.e., how the read and write throughputs are affected by data-access delay, the RAID level, and queuing.
Advances in technologies for scanning, networking, and CD-ROM, lower prices for large disk storage, and acceptance of common image compression and file formats have contributed to an increase in the number, size, and ...
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ISBN:
(纸本)081941767X
Advances in technologies for scanning, networking, and CD-ROM, lower prices for large disk storage, and acceptance of common image compression and file formats have contributed to an increase in the number, size, and uses of on-line image collections. New tools are needed to help users create, manage, and retrieve images from these collections. We are developing QBIC (query by image content), a prototype system that allows a user to create and query imagedatabases in which the image content - the colors, textures, shapes, and layout of images and the objects they contain - is used as the basis of queries. This paper describes two sets of algorithms in QBIC. The first are methods that allow `query by color drawing,' a form of query in which a user draws an approximate color version of an image, and similar images are retrieved. These are automatic algorithms in the sense that no user action is necessary during database population. Secondly, we describe algorithms for semi-automatic identification of image objects during database population, improving the speed and usability of this manually-intensive step. Once outlined, detailed queries on the content-properties of these individual objects can be made at query time.
We report a database language for visual retrieval which allows queries on image feature information which has been computed and stored along with images. The language is novel in that it provides facilities for deali...
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ISBN:
(纸本)0819411418;9780819411419
We report a database language for visual retrieval which allows queries on image feature information which has been computed and stored along with images. The language is novel in that it provides facilities for dealing with feature data which has actually been obtained from image analysis. Each line in the Manchester Visual Query Language (MVQL) takes a set of objects as input and produces another, usually smaller, set as output. The MVQL constructs are mainly based on proven operators from the field of digital image analysis. An example is the Hough-group operator which takes as input a specification for the objects to be grouped, a specification for the relevant Hough space, and a definition of the voting rule. The output is a ranked list of high scoring bins. The query could be directed towards one particular image or an entire image database, in the latter case the bins in the output list would in general be associated with different images. We have implemented MVQL in two layers. The command interpreter is a Lisp program which maps each MVQL line to a sequence of commands which are used to control a specialized database engine. The latter is a hybrid graph/relational system which provides low-level support for inheritance and schema evolution. In the paper we outline the language and provide examples of useful queries. We also describe our solution to the engineering problems associated with the implementation of MVQL.
Various methods of automatic shot boundary detection have been proposed and claimed to perform reliably. Although the detection of edits is fundamental to any kind of video analysis since it segments a video into its ...
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Various methods of automatic shot boundary detection have been proposed and claimed to perform reliably. Although the detection of edits is fundamental to any kind of video analysis since it segments a video into its basic components, the shots, only few comparative investigations on early shot boundary detection algorithms have been published. These investigations mainly concentrate on measuring the edit detection performance, however, do not consider the algorithms' ability to classify the types and to locate the boundaries of the edits correctly. This paper extends these comparative investigations. More recent algorithms designed explicitly to detect specific complex editing operations such as fades and dissolves are taken into account, and their ability to classify the types and locate the boundaries of such edits are examined. The algorithms' performance is measured in terms of hit rate, number of false hits, and miss rate for hard cuts, fades, and dissolves over a large and diverse set of video sequences. The experiments show that while hard cuts and fades can be detected reliably, dissolves are still an open research issue. The false hit rate for dissolves is usually unacceptably high, ranging from 50% up to over 400%. Moreover, all algorithms seem to fail under roughly the same conditions.
We present a prototype video database system designed to accept video sequences as well as still images. The system indexes these sequences based on scene changes, creates a primitive structure of these sequences, and...
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ISBN:
(纸本)081941767X
We present a prototype video database system designed to accept video sequences as well as still images. The system indexes these sequences based on scene changes, creates a primitive structure of these sequences, and searches this structure for queried objects using specific color features. A video sequence input to the database is first indexed into subsequences using a color histogram difference method. A hierarchical structure is created by thresholding the sequences at various levels of inter-frame difference. For every subsequence that is identified, the first frame in that subsequence, the representative frame, is entered into the database. The system then automatically generates a description for the frame in terms of its color histogram features. Subsequently, the video sequence may be searched for objects (specified as regions of other video sequence frames or still images) using color similarity matching.
With the advent of pervasive computing, a growing diversity of client devices is gaining access to audio-visual content. The increased variability in client device processing power, storage, bandwidth, and server load...
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ISBN:
(纸本)0780365364
With the advent of pervasive computing, a growing diversity of client devices is gaining access to audio-visual content. The increased variability in client device processing power, storage, bandwidth, and server loading require adaptive solutions for image, video and audio retrieval. Progressive retrieval is one prominent mode of access in which views at different resolutions are incrementally retrieved and refined over time. In this paper, we present a new framework for adaptively partitioning the synthesis operations in progressive retrieval of audio-visual signals. The framework considers that the server and client cooperate in synthesizing the views in order to best utilize the available processing power and bandwidth. We provide experimental results that demonstrate a significant reduction in latency in the progressive retrieval of images under different conditions of the client, server and network.
Multimedia data is generally stored in compressed form in order to efficiently utilize the available storage facilities. Access to archives is dependent on our ability to browse compressed multimedia information - ret...
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Multimedia data is generally stored in compressed form in order to efficiently utilize the available storage facilities. Access to archives is dependent on our ability to browse compressed multimedia information - retrieval and tracking from coded videodatabases. In this paper, a novel visual search engine for videoretrieval and tracking from compressed multimedia databases is proposed. The goal of the project is the implementation of a visual browser that operates in a distributed environment where users initiate video searches and retrieve relevant video information simultaneously from multiple video archives. Being presented with a query in the form of template images of objects, the system operates on the compressed video to find the images or video sequences where those objects are present and their positions in the image. Upon user's request, the system will decompress and display only the video sequences of interest.
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