IEEE Transactions on Circuits and Systems for Video Technology

While overlapped block motion compensation (OBMC) with block matching motion vectors yields better estimation accuracy than standard block matching, these estimates may be significantly improved by optimizing the motion vectors. Optimal motion vectors may be determined by an iterative and computationally intensive process. However, for a low-cost system (e.g., videoconferencing), such an approach ... View full abstract»

This paper describes a data-interlacing architecture with two-dimensional (2-D) data-reuse for full-search blockmatching algorithm. Based on a one-dimensional processing element (PE) array and two data-interlacing shift-register arrays, the proposed architecture can efficiently reuse data to decrease external memory accesses and save the pin counts. It also achieves 100% hardware utilization and a... View full abstract»

This paper shows that using the Loeffler's (see Proc. IEEE ICASSP, vol.2, p.988-91, 1989) one-dimensional (1-D) 8-point discrete cosine transform (DCT) algorithm in Cho and Lee's (see ibid., vol.38, p.297-305, 1991) two-dimensional (2-D) 8/spl times/8-point DCT algorithm will result in an optimal algorithm in the sense of multiplicative complexity theory. View full abstract»

The hardware implementation issues for an adaptive multialphabet arithmetic coder are discussed. A simple weighted history model is proposed to encode the video data. This model uses a weighted finite buffer to model the cumulative density function of the arithmetic coder. The performance of the weighted history model is evaluated together with several other well-known models. To access, search, a... View full abstract»

Several works have concluded that the number of cells per frame of variable bit-rate (VBR) video teleconference follows a gamma distribution. But few video models meet this characteristics. We propose a novel video model, called first-order autoregressive (AR) gamma sequence, in which random variables are marginally distributed as gamma variables. We give the definition of a GAR model and a simple... View full abstract»

An innovative selective coefficient discrete cosine transform (SCDCT) architecture is proposed which is designed for selective coefficient computation and straightforward row-column computation. Having these features, the selective coefficient DCT core will fit for various area/speed requirements. It can save the transposition delay to simplify the computation flow of two-dimensional (2-D) DCT and... View full abstract»

Motion estimation and compensation is widely used for exploiting temporal correlation within an image sequence. To find motion vectors that lead to high compression, most motion estimation approaches use a source distortion measure, such as mean-square error (MSE) or mean-absolute error (MAE), as a search criterion. When incorporated into a closed-loop motion compensated (MC) transform video coder... View full abstract»

Digital video transmission across the network is now widely used in the Internet community. Visual information transmission will no doubt play an important role in a future national information infrastructure (NII). Very often, however, the channel bandwidth is fixed. Therefore, video coding based on an appropriate bit-rate control is a key to the success of accommodating visual communication in N... View full abstract»

A rate-distortion framework is used to define a displacement vector field estimation technique for use in video coding. This technique achieves maximum reconstructed image quality under the constraint of a target bit rate for the coding of the vector sequence. The technique may be adapted so as to limit its smoothing effect to homogeneous areas and avoid highly textured areas and edges. Use of thi... View full abstract»

A video coding method called model-based image coding has attracted much attention as a potential candidate for low bit-rate visual communication services. This technique reconstructs the facial image with a preknown 3D human face model and its received model motion parameters. The parameters of the head motion are mainly divided into two parts: global motion parameters describe the rigid movement... View full abstract»

Several methods have been proposed to do color quantization for limited color displays. Self-organization of Kohonen feature maps (SOFM) is a very useful tool for data clustering. By extracting a special butterfly-jumping sequence from an image, a neural network was fed in that sequence of image data for SOFM training, and a fairly good color table was present to represent that image. The peak sig... View full abstract»

Labeling algorithms for construction-A and construction-B lattices with respect to pyramid boundaries are presented. The algorithms are developed based on relations between lattices and linear block codes as well as on transformations among several specifically defined lattices and their translations. The mechanism for the construction of these algorithms can be considered as an extension of that ... View full abstract»

The detection and correction approach to transmission errors in JPEG images using the sequential discrete cosine transform (DCT)-based mode of operation is proposed. The objective is to eliminate transmission errors in JPEG images. Here a transmission error may be either a single-bit error or a burst error containing N successive error bits. For an entropy-coded JPEG image, a single transmission e... View full abstract»