41515158
Error resilience for block loss with overlapped motion compensation
A new error resilience algorithm for recovering the lost blocks or motion vectors is presented. It combines the overlapped motion compensation and the side match criterion to make the effect of lost blocks subjectively imperceptible. The side match criterion takes advantage of the spatial contiguity and interpixel correlation of image to select the best-fit replacement among the motion vectors of spatially contiguous candidate blocks. Particularly, to mask the blocking artifacts, we incorporate an overlapping technique to create a subjectively closer approximation to the true error-free image.
38112853
Low power full-search block-matching motion estimation chip for H.263+
In this paper, a low power full-search block matching (FSBM) motion estimation design for the H.263+ low bit rate video coding was proposed. The features of H.263+ such as half-pixel precision and some advanced modes (advance prediction mode, PB-frame mode and reduced resolution update mode) are taken into consideration. This architecture can deal with different block size and searching range in a single chip without any latency. We use a 1-D and 2-D mixed architecture to fulfill this goal. To achieve the purpose of low power and reduce the design period, we use dual supply voltage levels in this chip. This chip is realized by TSMC 0.6 /spl mu/m single-poly triple-metal CMOS technology. The operation frequency is set at 60 MHz to meet the requirement of the real time processing in the reduced resolution update mode in H.263+. The power consumption is 424 mW at 60 MHz and the throughput is 36 frames per second with CIF format at 60 MHz.
4181067
Error-propagation analysis and concealment strategy for MPEG-4 video bitstream with data partitioning
Data partitioning, one of the MPEG-4 video error resilience tools, enables better error robustness. However, it suffers from serious error propagation problem. In this paper, we use an experimental approach to model the error propagation with several commonly used error detection conditions. It is shown that errors detected in forward section of texture data may be propagated from motion data, while those in DCT coefficients mostly result from themselves. Furthermore, the motion marker is the major error source for several error conditions detected in motion part. According to these characteristics, motion marker assumption and backtracking-based concealment strategies are proposed to achieve more accurate error localization in bitstream domain.
43431226
Wavelet-based optical flow estimation
A new algorithm for accurate optical flow (OF) estimation using discrete wavelet approximation is proposed. The computation of OF depends on minimizing the image and smoothness constraints. The proposed method takes advantages of the nature of wavelet theory, which can efficiently and accurately approximate any function. OF vectors and image functions are represented by means of linear combinations of scaling basis functions. Based on such wavelet-based approximation, the leading coefficients of these basis functions carry global information about the approximated functions. The proposed method can successfully convert the problem of minimizing a constraint function into that of solving a linear system of a quadratic and convex function of scaling coefficients. Once all the corresponding coefficients are determined, the flow vectors can be obtained accordingly. Experiments have been conducted on both synthetic and real image sequences. In terms of accuracy, the results show that our approach outperforms the existing methods which adopted the same objective function as ours.
9822806
Wavelet-based optical flow estimation
In this paper, a new algorithm for accurate optical flow estimation using discrete wavelet approximation is proposed. The proposed method takes advantages of the nature of wavelet theory, which can efficiently and accurately represent "things", to model optical flow vectors and image related functions. Each flow vector and image function are represented by linear combinations of wavelet basis functions. From such wavelet-based approximation, the leading coefficients of these basis functions carry the global information of the approximated "things". The proposed method can successfully convert the problem of minimizing a constraint function into that of solving a linear system of a quadratic and convex function of wavelet coefficients. Once all the corresponding coefficients are decided, the flow vectors can be determined accordingly. Experiments conducted on both synthetic and real image sequences show that our approach outperformed the existing methods in terms of accuracy.
8575175
A User-Friendly Methodology for Automatic Exploration of Compiler Options
This paper introduces a practical methodology for automatic exploring compiler optimization options. The strategy behind this methodology is to provide an intelligent mechanism, in which the compiler will automatically identify optimized combination of compiler options for a given application. The decision made by the compiler is based on user requirements on what aspects of the generated code are the most critical for the compiled application through a specialized user interface. A set of pre-built databases of candidate optimized combinations of compiler options will help the compiler to make the right decision. This methodology will dramatically help users to get rid of the burden of fully understanding the compiler’s inner structure and organization to make the most profitable combination of options. All this work is taken by the compiler and the infrastructure proposed in this paper. This paper presents this methodology and describes its principles and technical mechanisms of the components.
17553402
Efficient Parallel Algorithms for Euclidean Distance Transform
The Euclidean Distance Transform (EDT) converts a binary image into one where each pixel has a value equal to its distance to the nearest foreground pixel. Two parallel algorithms for EDT transform on linear array with reconfigurable pipeline bus system (LARPBS) are presented. For an image with n×n pixels, the first algorithm can complete EDT transform in ) log log log log log log ( n n n O time using n processors. The second algorithm can compute the EDT in O( log n loglog n) time using n n log log 2 processors.
44509988
A threshold criterion, auto-detection and its use in MST-based clustering
Clustering is to group data points into homogenous clusters so that data points within the same cluster are more similar than data points belonging to different clusters. There are many effective clustering algorithms for discovering arbitrary shaped clusters, but one common problem of many algorithms is the difficulty for users to decide appropriate parameters for these algorithms. To reduce the dependence of clustering performance on parameters, this paper proposes a threshold criterion for the single linkage cluster analysis and incorporates it into the Minimum Spanning Tree (MST) based clustering method. Since the threshold can be automatically decided according to the underlying data distributions, arbitrary shaped clusters can be discovered with little human intervention. The experimental results on spatial data are very encouraging.