We propose a novel and simple fast block-matching algorithm (BMA), called adaptive rood pattern search (ARPS), which consists of two sequential search stages: (1) initial search and (2) refined local search. For each macroblock (MB), the initial search is performed only once at the beginning in order to find a good starting point for the follow-up refined local search. By doing so, unnecessary intermediate search and the risk of being trapped into local minimum matching error points could be greatly reduced in long search case. For the initial search stage, an adaptive rood pattern (ARP) is proposed, and the ARP's size is dynamically determined for each MB, based on the available motion vectors (MVs) of the neighboring MBs. In the refined local search stage, a unit-size rood pattern (URP) is exploited repeatedly, and unrestrictedly, until the final MV is found. To further speed up the search, zero-motion prejudgment (ZMP) is incorporated in our method, which is particularly beneficial to those video sequences containing small motion contents. Extensive experiments conducted based on the MPEG-4 Verification Model (VM) encoding platform show that the search speed of our proposed ARPS-ZMP is about two to three times faster than that of the diamond search (DS), and our method even achieves higher peak signal-to-noise ratio (PSNR) particularly for those video sequences containing large and/or complex motion contents.

Adaptive rood pattern search for fast block-matching motion estimation

The correspondence presents a fast exhaustive search algorithm for motion estimation. The basic idea is to obtain the best estimate of the motion vectors by successively eliminating the search positions in the search window and thus decreasing the number of matching evaluations that require very intensive computations. Simulation results demonstrate that although the performance of the proposed algorithm is the same as that using the exhaustive search, the computation time has been reduced significantly. >

Successive elimination algorithm for motion estimation

The Doppler technique has traditionally been the method used to extract motion information from ultrasonic echoes reflected by moving tissues. The Doppler technique has been around for a long time, and has been extensively reviewed and analyzed in the literature. Recently, time-domain methodologies for estimating tissue motion have gained in popularity. Time-domain methods have advantages over Doppler methods in many applications, and as of yet have not been comprehensively reviewed. An overview of time-domain techniques that have appeared in the literature over the past few years is presented. Their potential advantages over Doppler are examined, and the individual techniques are compared. >

Current time-domain methods for assessing tissue motion by analysis from reflected ultrasound echoes-a review

We propose a new fast algorithm for block motion vector (MV) estimation based on the correlations of the MVs existing in spatially and temporally adjacent as well as hierarchically related blocks. We first establish a basic framework by introducing new algorithms based on spatial correlation and then spatio-temporal correlations before integrating them with a multiresolution scheme for the ultimate algorithm. The main idea is to effectively exploit the information obtained from the corresponding block at a coarser resolution level and spatio-temporal neighboring blocks at the same level in order to select a good set of initial MV candidates and then perform further local search to refine the MV result. We show with experimental results that, in comparison with the full search algorithm, the proposed algorithm achieves a speed-up factor ranging from 150 to 310 with only 2-7% mean square error (MSE) increase and a similar rate-distortion performance when applied to typical test video sequences.

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Fast motion vector estimation using multiresolution-spatio-temporal correlations

Block matching motion estimation is the heart of video coding systems. During the last two decades, hundreds of fast algorithms and VLSI architectures have been proposed. In this paper, we try to provide an extensive exploration of motion estimation with our new developments. The main concepts of fast algorithms can be classified into six categories: reduction in search positions, simplification of matching criterion, bitwidth reduction, predictive search, hierarchical search, and fast full search. Comparisons of various algorithms in terms of video quality and computational complexity are given as useful guidelines for software applications. As for hardware implementations, full search architectures derived from systolic mapping are first introduced. The systolic arrays can be divided into inter-type and intra-type with 1-D, 2-D, and tree structures. Hexagonal plots are presented for system designers to clearly evaluate the architectures in six aspects including gate count, required frequency, hard-ware utilization, memory bandwidth, memory bitwidth, and latency. Next, architectures supporting fast algorithms are also reviewed. Finally, we propose our algorithmic and architectural co-development. The main idea is quick checking of the entire search range with simplified matching criterion to globally eliminate impossible candidates, followed by finer selection among potential best matched candidates. The operations of the two stages are mapped to the same hardware for resource sharing. Simulation results show that our design is ten times more area-speed efficient than full search architectures while the video quality is competitively the same.

/pdf/survey-on-block-matching-motion-estimation-algorithms-and-22go61s1gp.pdf

Survey on Block Matching Motion Estimation Algorithms and Architectures with New Results

For pt.I, see ibid., vol.37, no.3, p.97-101 (1991). A predictive block-matching motion estimation scheme was implemented for efficient video code design. The scheme is based on the so-called inertia effect of natural video scenes and takes advantage of the motion vectors obtained in the previous frames. The benefits from this prediction process are threefold. First, the searching area is greatly reduced, and so is the computational complexity. Second, the motion vector overhead information is reduced since motion vectors are decorrelated by the prediction process. Finally, the motion vectors estimated from this procedure are more realistic since it reflects the real physical phenomena. These advantages were also demonstrated by simulation results including the coded data rate, displaced frame difference entropy, motion vectors, and reconstructed signal-to-noise ratio. Only a simple prediction model was implemented; further results in more general autoregressive (AR) modes are still under study. >

Predictive block-matching motion estimation for TV coding. II. Inter-frame prediction

A novel motion estimation/compensation scheme for full-motion interframe video compression is proposed. This scheme is based on prediction of interblock motion information by using minimum absolute difference block matching and hence substantially increases the searching and computation efficiency. A comparison is made with the 'optimal' full motion searching scheme for a standard test sequence. The experimental results show that the proposed scheme provides a computationally efficient algorithm in a real-time video communication environment. >

Predictive block-matching motion estimation schemes for video compression. I. Inter-block prediction

For pt. I see ibid., vol.2, p.1088 (1991). A novel predictive block matching motion estimation scheme is proposed for efficient video codec design. The proposed scheme is based on the 'inertia' effect of natural video scenes and takes advantage of the motion vectors obtained in the previous frames. Not only are motion searching time and overhead significantly reduced, but the proposed scheme also provides a realistic motion tendency, which is very useful for frame-skipping/interpolation techniques. These advantages are demonstrated by experimental results obtained on the Abekas video system. >

Y.-Q. Zhang

Papers

Predictive block-matching motion estimation for TV coding. II. Inter-frame prediction

Predictive block-matching motion estimation schemes for video compression. I. Inter-block prediction

Predictive block-matching motion estimation schemes for video compression. II. Inter-frame prediction of motion vectors