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.
A key aspect of imageretrieval using color, is the creation of robust and efficient indices. In particular, the color histogram remains the most popular index, due primarily to its simplicity. However, the color hist...
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A key aspect of imageretrieval using color, is the creation of robust and efficient indices. In particular, the color histogram remains the most popular index, due primarily to its simplicity. However, the color histogram has a number of drawbacks. Specifically, histograms capture only global activity, they require quantization to reduce dimensionality, are highly dependent on the chosen color space, have no means to exclude a certain color from a query and can provide erroneous results due to gamma nonlinearity. In this paper we present a vector angular distance measure which is implemented as part of our database system. Our system does away with histogram techniques for color indexing and retrieval and instead implements color vector techniques. We use color segmentation to extract regions of prominent color and use representative vectors from these extracted regions in the image indices. this way we end up with a much smaller index which does not have the granularity of a histogram. Instead similarity is based on our vector angular distance measure between a query color vector and the indexed representative vectors.
For the last few years, shot boundary detection has been recognized as an important research issue on videoretrieval. Also as a preliminary step for the task, it is essential to extract salient features from videos. ...
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For the last few years, shot boundary detection has been recognized as an important research issue on videoretrieval. Also as a preliminary step for the task, it is essential to extract salient features from videos. Recently, it has become common to perform the two tasks in compressed domain to alleviate their computational costs. In this paper, we propose novel shot boundary detection technique, which uses two feature images, or DC and edge images, extracted directly from MPEG compressed video. While a DC image can be easily obtained, edge image extraction usually requires considerable computational burden. For fast edge image extraction, we suggest to utilize only a few AC coefficients of each DCT block in motion compensated P-frames and B-frames as well as I-frames. this drastically reduces the computational burden compared to edge extraction in the spatial domain. In order to further reduce the computational burden, another edge image extraction technique is also suggested on the basis of AC prediction using DC images. By using the edge energy diagram obtained from edge images and histograms from DC images, shot boundaries such as abrupt transitions, fades, and dissolves are detected automatically. Simulation results show that the proposed techniques are fast and effective.
We have developed a wide-area-distributed storage system for multimedia databasesthat 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 databasesthat 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.
Illumination invariance is of paramount importance to annotate video sequences stored in large videodatabases consistently. Yet, popular texture analysis methods such as multichannel filtering techniques do not yield ...
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Illumination invariance is of paramount importance to annotate video sequences stored in large videodatabases consistently. Yet, popular texture analysis methods such as multichannel filtering techniques do not yield illumination-invariant texture representations. In this paper, we assess the effectiveness of three illumination normalisation schemes for texture representations derived from Gabor filter outputs. the schemes aim at overcoming intensity scaling effects due to changes in ilumination conditions. A theoretical analysis and experimental results enable us to select one scheme as the most promising one. In this scheme, a normalising factor is derived at each pixel by combining the energy responses of different filters at that pixel. the scheme overcomes illumination variations well, while still preserving discriminatory textural information. Further statistical analysis may shed light on other interesting properties or limitations of the scheme.
image search has been actively studied in recent years. On the other hands, image browsing has received little attention. image browsing refers to the process of presenting some forms of overview or summary of the ima...
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image search has been actively studied in recent years. On the other hands, image browsing has received little attention. image browsing refers to the process of presenting some forms of overview or summary of the image relationships, thus facilitating a user to navigate across the data set and find images of interests. In this paper, we present a new data structure built on the multi-linearization of image attributes for efficient organization of the data set and fast visual browsing of the images. We describe new techniques for multi-linearization based on multiple space-filling curves and hierarchical clustering techniques. In addition to providing fast navigation, our proposed data structure allows computationally efficient insertion and deletion of images from the data set. We then present a novel image navigator and browser built on dual-linearization data structure and intuitive presentation of image relevance and relationships, demonstrate the image navigation process, and report results on 1000 and 22,000 imagedatabases. We also discuss how our data structure can be extended to support fast image search.
this paper addresses the problem of recovering the semantic structure of broadcast news. A hierarchy of retrievable units is automatically constructed by integrating information from different media. the hierarchy pro...
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this paper addresses the problem of recovering the semantic structure of broadcast news. A hierarchy of retrievable units is automatically constructed by integrating information from different media. the hierarchy provides a compact yet meaningful abstraction of the broadcast news data similar to a conventional table of content that can serve as an effective index table, facilitating the capability of browsing through large amounts of data in a non-linear fashion. the recovery of the semantic structure of the data further enables the automated solutions in constructing visual representations that are relevant to the semantics as well as in establishing useful relationships among data units such as topic categorization and content based multimedia hyperlinking. Preliminary experiments of integrating different media for hierarchical segmentation of semantics have yielded encouraging results. Some of the results are presented and discussed in this paper.
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.
this paper presents a simple and effective pre-processing method developed for the segmentation of MPEG compressed video sequences. the proposed method for scene-cut detection only involves computing the number of bit...
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this paper presents a simple and effective pre-processing method developed for the segmentation of MPEG compressed video sequences. the proposed method for scene-cut detection only involves computing the number of bits spent for each frame (encoding cost data), thus avoiding decoding the bitstream. the information is separated into I-, P-, B-frames, thus forming 3 vectors which are independently processed by a new peak detection algorithm based on overcomplete filter banks and on joint thresholding using a confidence number. Each processed vector yields a set of candidate frame numbers, i.e. 'hints' of positions where scene-cuts may have occurred. the 'hints' for all frame types are recombined into one frame sequence and clustered into scene cuts. the algorithm was not designed to distintuish among types of cuts but rather to indicate its position and duration. Experimental results show that the proposed algorithm is effective in detecting abrupt scene changes as well as gradual transitions. For precision demanding applications, the algorithm can be used with a low confidence factor just to select the frames that are worth being investigated by a more complex algorithm. the algorithm is not particularly tailored to MPEG and can be applied to most video compression techniques.
the aim of this report is to be controversial and to engage a debate within the research community. Issues of whether some of the work in image and videodatabases has been directed at solutions in search of a problem...
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the aim of this report is to be controversial and to engage a debate within the research community. Issues of whether some of the work in image and videodatabases has been directed at solutions in search of a problem are discussed. Important applications in the area of media-based digital libraries that will enhance human experience are also detailed.
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