IEEE Transactions on Circuits and Systems for Video Technology

An efficient technique for summarization of stereoscopic video sequences is presented, which extracts a small but meaningful set of video frames using a content-based sampling algorithm. The proposed video-content representation provides the capability of browsing digital stereoscopic video sequences and performing more efficient content-based queries and indexing. Each stereoscopic video sequence... View full abstract»

This paper describes a novel cooperative procedure for the segmentation of multiview image sequences exploiting multiple sources of information. Compared to other approaches, no a priori information is needed about the structure and the arrangement of objects in the scene. Three cameras in a particular unsymmetrical set-up are used in the system. The color distribution and the object contours in t... View full abstract»

This paper describes a novel framework for object extraction from images utilizing multiple cameras. Focused regions in images and disparities of point correspondences among multiple images are 3-D clues for the extraction. We examine the extraction of focused objects from images by these automatically acquired clues. Edges in images captured by the cameras are detected, and disparities of the edg... View full abstract»

The estimation of rigid-body 3-D motion parameters using point correspondences from a pair of images under perspective projection is, typically, very sensitive to noise. We present a novel robust method combining two approaches: (1) the SVD analysis of a linear operator resulting from the feature points and the displacement vectors and (2) a modified version of the well-known weighted least-square... View full abstract»

We propose a generic algorithm for the geometrically correct reconstruction of 3-D scenes on stereo displays with viewpoint adaptation. This forms the basis of multiviewpoint systems, which are currently the most promising candidates for real-time implementations of 3-D visual communication systems. The reconstruction algorithm needs 3-D tracking of the viewers' eyes with respect to the display. W... View full abstract»

Efficient techniques are introduced in this paper for the identification of the occlusion and visible background and foreground areas in a noisy stereoscopic image pair. Three different Bayes decision methods are tested for this purpose. The first, and uses three hypotheses for the formulation of the Bayes decision rules, adopting the right image as a reference. After performing a dual-Bayes decis... View full abstract»

Binocular camera systems are commonly used to construct 3-D-based scene description. However, there is a tradeoff between the length of the camera baseline and the difficulty of the matching problem and the extent of the field of view of the 3-D scene. A large baseline system provides better depth resolution than a smaller baseline system at the expense of a narrower field of view. To increase the... View full abstract»

A fast search algorithm for vector quantization (VQ) is presented. This approach provides a practical solution to the implementation of a multilevel search based on a special designed directed graph (DG). An algorithm is also given of the optimal DG for any given practical source. Simulation results obtained from applying this approach to still images have shown that it can reduce the searching co... View full abstract»

For fast vector quantization (VQ) encoding, we present in this paper a new method to speed up the calculation of the squared Euclidean distance between two vectors. We call it the approximated look-up table (ALUT) method. This method considers the frequency of each squared number that occurs in the equation of squared Euclidean distances, and generates a more practical table to store squared numbe... View full abstract»

A precise error tracking scheme for robust transmission of real-time H.263 video is presented. By utilizing a feedback channel, the decoder reports the addresses of corrupted blocks induced by transmission errors back to the encoder. With these negative acknowledgments, the encoder can precisely calculate and track the propagated errors by examining the backward motion dependency for each pixel in... View full abstract»

This work presents a low-complexity high-performance motion estimation method using a one-dimensional (1-D) gradient descent search. The proposed method consists of initial-point determination, initial-direction determination, a gradient descent search using variable step sizes and conjugate directions, and convergence checking. For each block, one of the original and predictive points with the be... View full abstract»

At present, block-transform coding is probably the most popular approach for image compression. However, for the sake of its implementation, an image is partitioned into spatially adjoining blocks which are processed independently without considering inter-block correlation. So, this approach inescapably causes an annoying defect called a blocking artifact. In this letter, in order to reduce a blo... View full abstract»

We describe a semi-automatic approach for segmenting a video sequence into spatio-temporal video objects in the presence of occlusion. Motion and shape of each video object is represented by a 2-D mesh. Assuming that the boundary of an object of interest is interactively marked on some keyframes, the proposed method finds the boundary of the object in all other frames automatically by tracking the... View full abstract»

Digital data hiding is a technology being developed for multimedia services, where significant amounts of secure data is invisibly hidden inside a host data source by the owner, for retrieval only by those authorized. The hidden data should be recoverable even after the host has undergone standard transformations, such as compression. In this paper, we present a source and channel coding framework... View full abstract»

The MPEG-2 compression algorithm is very sensitive to channel disturbances due to the use of variable-length coding. A single bit error during transmission leads to noticeable degradation of the decoded sequence quality, in that part or an entire slice information is lost until the next resynchronization point is reached. Error concealment (EC) methods, implemented at the decoder side, present one... View full abstract»

Audio-visual and other multimedia services are seen as important sources of traffic for future telecommunication networks, including wireless networks. A major drawback with some wireless networks is that they introduce a significant number of transmission errors into the digital bitstream. For video, such errors can have the effect of degrading the quality of service to the point where it is unus... View full abstract»