Fast sub-pixel motion estimation having lower complexity
17 Jun 2003-pp 174-175
TL;DR: In this paper, the authors presented fast sub-pixel motion estimation based on mathematical models of the motion compensated errors for moving picture compression, which need no interpolation from the integer-pixel search results.
Abstract: This paper presents fast sub-pixel motion estimation having less computational complexity. The proposed methods are based on mathematical models of the motion compensated errors for moving picture compression. The methods need no interpolation from the integer-pixel search results. In order to decide the coefficients of the models, the motion compensated errors of the neighboring pixels around motion vectors are used. The errors were already obtained during the pixel accuracy full search. The models estimate the motion compensated errors at sub-pixel accuracy level. The proposed mathematical models are referred to as Model 1, Model 2, Model 3, modified Model 2, and modified Model 3, respectively. The simulation results show that the performance depends on the accuracy of the models. The performance of the proposed methods, having less computational complexity, is close to that of the full search method.
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16 Jul 2012
TL;DR: An efficient FME algorithm and architecture that significantly reduce the number of the candidate sub-pixels by predicting quarter motion vector and cost less hardware by saltatory interpolation is proposed and verified in an AVS HD encoder on a Xilinx Virtex-6 FPGA prototype system.
Abstract: Fractional motion estimation (FME) as a complement to integer motion estimation (IME) conducts higher compression rate in video coding. Based on multiple reference frames and all modes of variable-block-size (VBS) motion search, the common FME algorithm and architecture generally causes high computational complexity. It consumes plenty of time and hardware resources to process the real-time (30fps) high definition (HD) video compression. In this paper, we propose an efficient FME algorithm and architecture that significantly reduce the number of the candidate sub-pixels by predicting quarter motion vector and cost less hardware by saltatory interpolation. Compared with the conventional FME architecture, the proposed method reduces resources significantly and accelerates the processing speed. 75% circuit area and 68% computational complexity are saved with only 0.1dB drop in performance and similar bit rate saving on average. Experiments of various sequences show that HD video (1920×1080) can be processed in real-time at frequency of 100MHz and it is verified in an AVS HD encoder on a Xilinx Virtex-6 FPGA prototype system.
4 citations
Cites methods from "Fast sub-pixel motion estimation ha..."
...So some previous researches focus on optimizing algorithm to reduce the search points, Jeong Jechang’s work was at the model using the parameters derived from the neighboring integer pixels’ sum of absolute difference (SAD) to estimate the sub-pixels SAD [9]....
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TL;DR: The mathematics of bilinear interpolation are utilized for the selection of the candidate motion vectors that minimize the error criterion, by estimating local minima in the error surface with arbitrary accuracy.
Abstract: The present paper focuses on high-accuracy block-based sub-pixel motion estimation utilizing a straightforward error minimization approach. In particular, the mathematics of bilinear interpolation are utilized for the selection of the candidate motion vectors that minimize the error criterion, by estimating local minima in the error surface with arbitrary accuracy. The implemented approach favors optimum accuracy over computational load demands, making it ideal as a benchmark for faster methods to compare against; however, it is not best suited to real-time critical applications (i.e. video compression). Other video processing needs relying on motion vectors and requiring high-resolution/accuracy can also take advantage of the proposed solution (and its simplified nature in terms of underlying theoretical complexity), such as motion-compensation filtering for super resolution image enhancement, motion analysis in sensitive areas (e.g. high-speed video monitoring, medical imaging, motion analysis in sport science, big-data visual surveillance, etc.). The proposed method is thoroughly evaluated using both real video and synthetic motion sequences from still images, adopting well-tested block-based motion estimation evaluation procedures. Assessment includes comparisons to a number of existing block-based methods with respect to PSNR and SSIM metrics over ground-truth samples. The conducted evaluation takes into consideration both the original (arbitrary-accuracy) and the truncated motion vectors (after rounding them to the nearest half, quarter, or eighth of a pixel), where superior performance with more accurate motion vector estimation is revealed. In this context, the degree to which sub-pixel motion estimation methods actually produce sub-pixel motion vectors is investigated, and the implications thereof are discussed.
4 citations
Cites methods from "Fast sub-pixel motion estimation ha..."
...In [22, 43], Jeong and Suh describe a variety of methods that offer better results in half-pixel accuracy ME....
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...While this is certainly much slower than state of the art fast sub-pixel ME methods [11, 22, 31, 36, 41, 43, 44, 51, 55, 56], this is not perceived as a significant flaw, considering that the present work favors ME accuracy over execution speed....
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TL;DR: Experimental evidence that for coding image sequences in hemodynamics, an adequate motion compensation scheme can be more efficient than the still-image coding methods often used nowadays is presented.
4 citations
TL;DR: Experimental results show that the proposed adaptive FME/IME algorithm can help the encoder generate a bit stream at much lower computational complexity with small degradation in the coding gain as compared with a pure FME algorithm.
Abstract: The performance of the motion-compensated prediction (MCP) in video coding is degraded by aliasing due to spatial sampling. To alleviate this problem in H.264/AVC, a low-pass filter is used by the fractional-pel motion estimation (FME) to suppress the aliasing component. However, the FME demands higher computational complexity on H.264/AVC encoding. In this work, we first perform a joint quantization and aliasing analysis on the H.264/AVC MCP process and show that the impact of the aliasing component can be alleviated by the quantization process. Then, we propose a fast motion estimation (ME) algorithm that uses the FME and the integer-pel motion estimation (IME) adaptively. The adaptive FME/IME algorithm examines the coding modes of the reference block for the current coding block, and then decides whether the FME or the IME should be applied to the current coding block. Experimental results show that the proposed adaptive FME/IME algorithm can help the encoder generate a bit stream at much lower computational complexity with small degradation in the coding gain as compared with a pure FME algorithm.
3 citations
Dissertation•
01 Jan 2007TL;DR: The primary objective of this thesis is to provide a low-complexity rate-distortion optimal coding mode selection method in digital video encoding and extends the model-based mode selection approach to motion vector selection for further improvement of the coding efficiency.
Abstract: The primary objective of this thesis is to provide a low-complexity rate-distortion optimal coding mode selection method in digital video encoding. To achieve optimal compression efficiency in the rate-distortion framework with low computational complexity, we first propose a rate-distortion model and then apply it to the coding mode selection problem. The computational complexity of the proposed method is very low compared to overall encoder complexity because the proposed method uses simple image properties such as variance that can be obtained easily. Also, the proposed method gives significant PSNR gains over the mode selection scheme used in TM5 for MPEG-2 because the rate-distortion model considers rate constraints of each mode as well as distortion. We extend the model-based mode selection approach to motion vector selection for further improvement of the coding efficiency.
In addition to our theoretical work, we present practical solutions to real-time implementation of encoder modules including our proposed mode selection method on digital signal processors. First, we investigate the features provided by most of the recent digital signal processors, for example, hierarchical memory structure and efficient data transfer between on-chip and off-chip memory, and then present practical approaches for real-time implementation of a video encoder system with efficient use of the features.
2 citations
Cites background from "Fast sub-pixel motion estimation ha..."
...Many fast schemes have been proposed to decrease computational complexity in [20, 24, 33, 34, 42, 52, 53]....
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