IEEE Transactions on Circuits and Systems for Video Technology

In this paper, we present an alternative framework for video processing without explicit motion estimation or segmentation. Motivated by the geometric constraint of motion trajectory, we propose an adaptive filtering-based model for video signals in which filter coefficients are locally estimated by the least-square method. Such localized estimation can be viewed as an implicit approach of exploit... View full abstract»

This paper presents a stochastic estimation approach to adaptive interpolation of color filter array. It models an image as a 2D locally stationary Gaussian process and achieves robustness against aliasing by employing an edge-sensitive weighting policy based on the stochastic characteristics of uniformly oriented edge indicators. Experimental results show that the algorithm can effectively elimin... View full abstract»

We present an efficient content-based image coding called locally adaptive resolution (LAR) offering advanced scalability at different semantic levels, i.e., pixel, block, and region. A local analysis of image activity leads to a nonuniform block representation supporting two layers of image description. The first layer provides global information encoded in the spatial domain enabling a low bit r... View full abstract»

This paper addresses the problem of deriving measures that express the degree of the reliability of motion vectors estimated by a block-matching motion estimation method. We express the block matching motion estimation scheme in the probabilistic framework as a maximum-likelihood estimation scheme. Subsequently, we derive the confidence measures in terms of the a posteriori probabilities and the l... View full abstract»

This paper points out some defects in the techniques used in H.264 rate control and presents several new algorithms to improve them. The improved algorithm has the following main features: 1) the bits allocated to each P-frame is proportional to the local motion in it, i.e, more bits are allocated to a frame if the local motion in it is stronger; 2) the quantization parameter for I-frame is choose... View full abstract»

Quantization-based embedding has been used for integrity verification in semi-fragile watermarking. However, some of the illegal modifications cannot be detected in the normal quantization-based methods, especially when the host values (i.e., the values chosen in a host signal for data embedding) are independent from each other. In this paper, a sequential quantization strategy (SQS) is proposed t... View full abstract»

The perceived video quality in a wireless streaming application strongly depends on the channel's dynamics and the fluctuations of the source bit rate. In this paper, we introduce two channel-adaptive rate control schemes for slowly and fast varying channels, respectively. Both schemes account for the playback buffer occupancy in the joint optimization of the source rate and channel-code forward e... View full abstract»

Providing quality of service (QoS) for Internet-based video streaming applications requires the server and/or client to be network-aware and adaptive. We present a dynamic rate and quality adaptation algorithm where the server varies its sending rate (without varying the quality level) to adapt to the network and client conditions and only as a last resort, does quality adaptation. We place the ad... View full abstract»

In order to take advantage of the byte-type data parallelism in the existing single-instruction multiple-data (SIMD) technique, this paper introduces the concept of 8-bit partial sums, obtained by a 4-bit right-shift operation on the sum of the 16 luminance values in a column of a 16 x 16 block of a video frame. Since these partial sums are of only eight bits, eight of them can be processed concur... View full abstract»

This paper presents an error concealment processor to increase the performance of the TV receiver while the decoding bit stream over error-prone channel suffers from damage. An efficient error-concealment algorithm is advised with the adaptation of the spatial interpolation and the temporal prediction to reduce the nonmatched error for high motion regions and achieve fine resolution for still or l... View full abstract»

A high-speed VLSI design of an area-efficient JPEG2000 encoder is given. Recursive multilevel 2D discrete wavelet transform (DWT) architecture with dual buffers is proposed to reduce the wavelet coefficients memory to 1/4 tile size, prerate allocation is used to reduce the compressed code memory to 3/4 tile size. A highly pipelined and parallelism implementation of line-based 1-level DWT is propos... View full abstract»

In this paper, we propose a generalized discrete cosine transform (DCT) decimation scheme for DCT-domain spatial downscaling which performs two-fold decimation on subframes of a flexible size larger than the traditional 8 times 8 block size to improve the visual quality. Efficient sparse-matrix representations are then derived to reduce the computation of the proposed DCT decimation method. We com... View full abstract»

This paper presents a novel B-picture coding based on block-wise adaptive motion accuracy (BAMA) with low-complexity motion compensation (MC). BAMA is able to adaptively select the motion accuracy for each inter-block in a B-picture depending on whether it is of bidirectional prediction, in which compared to the unidirectionally predicted block, lower motion accuracy is applied to the bidirectiona... View full abstract»