IEEE Transactions on Circuits and Systems for Video Technology

Video communications over wireless networks often suffer from various errors. A novel video transmission architecture is proposed to meet the low-delay and error-robust requirement of wireless video communications. This architecture uses forward error correction coding and automatic repeat request (ARQ) protocol to provide efficient bandwidth access from wireless link. In order to reduce ARQ delay... View full abstract»

Layered multicast is an efficient technique to deliver video to heterogeneous receivers over wired and wireless networks. We consider such a multicast system in which the server adapts the bandwidth and forward-error correction code (FEC) of each layer so as to maximize the overall video quality, given the heterogeneous client characteristics in terms of their end-to-end bandwidth, packet drop rat... View full abstract»

An important and unsolved problem today is that of automatic quantification of the quality of video flows transmitted over packet networks. In particular, the ability to perform this task in real time (typically for streams sent themselves in real time) is especially interesting. The problem is still unsolved because there are many parameters affecting video quality, and their combined effect is n... View full abstract»

In this paper, motion vector (MV) estimation methods with high-speed intermediate pictures for low-power video compression are proposed. The intermediate pictures are obtained by a special type of CMOS image sensor. An adaptive iterative-search block matching is proposed to obtain precise MVs of video-rate pictures from high-speed intermediate pictures with the reduced computational complexity. Th... View full abstract»

Due to the large amount of data transfers it involves, the motion estimation (ME) engine is one of the most power-consuming components of any predictive video codec. As a consequence, power-optimized video coding primarily relies on a carefully designed motion estimator. This paper first presents a block ME algorithm that meets high-quality inter-frame prediction and low computational complexity r... View full abstract»

We describe an object-based video compression scheme based on the derivation and efficient coding of motion boundaries. First, we recursively identify a small number of global movement classes, each represented by two or more motion parameters. Second, we assign regions of a spatial segmentation to movement classes. Third, we merge segments using various similarity heuristics, while adding movemen... View full abstract»

An efficient and computationally fast method for segmenting text and graphics part of document images based on textural cues is presented. We assume that the graphics part have different textural properties than the nongraphics (text) part. The segmentation method uses the notion of multiscale wavelet analysis and statistical pattern recognition. We have used M-band wavelets which decompose an ima... View full abstract»

Key frames are the subset of still images which best represent the content of a video sequence in an abstracted manner. In other words, video abstraction transforms an entire video clip to a small number of representative images. We present a scheme for object-based video abstraction facilitated by an efficient video-object segmentation (VOS) system. In such a framework, the concept of a "key fram... View full abstract»

Blocking artifacts continue to be among the most serious defects that occur in images and video streams compressed to low bit rates using block discrete cosine transform (DCT)-based compression standards (e.g., JPEG, MPEG, and H.263). It is of interest to be able to numerically assess the degree of blocking artifact in a visual signal, for example, in order to objectively determine the efficacy of... View full abstract»

Blockiness is a typical artifact in reconstructed images that have been coded by a block-based discrete cosine transform (BDCT). In highly compressed images and video, the blocking artifacts are easily noticeable as the discontinuities between relatively homogeneous regions. Many current noniterative de-blocking algorithms attempt to remove the blocking artifacts by smoothing a few pixels around t... View full abstract»

Efficient VLSI architectures for motion estimation using the full-search block-matching algorithm are proposed in this paper. These structures are based on an improved and more efficient two-dimensional single-array architecture with minimum latency, maximum throughput, and full utilization of the hardware resources. This optimized architecture is extended to a class of fully parameterizable multi... View full abstract»

In block motion estimation, search patterns with different shapes or sizes and the center-biased characteristics of motion-vector distribution have a large impact on the searching speed and quality of performance. We propose a novel algorithm using a cross-search pattern as the initial step and large/small diamond search (DS) patterns as the subsequent steps for fast block motion estimation. The i... View full abstract»

We propose an efficient geometry compression algorithm for three-dimensional (3-D) mesh sequences based on the two-stage vertex-wise motion vector (MV) prediction. In general, the MV of a vertex is highly correlated to those of the adjacent vertices. To exploit this high correlation, we define the neighborhood of a vertex, and predict the MV of the vertex from those of the neighborhood. The error ... View full abstract»