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81.
Aiming at the higher bit-rate occupation of motion vector encoding and more time load of full-searching strategies,a multi-resolution motion estimation and compensation algorithm based on adjacent prediction of frame difference was proposed.Differential motion detection was employed to image sequences and proper threshold was adopted to identify the connected region.Then the motion region was extracted to carry out motion estimation and motion compensation on it.The experiment results show that the encoding efficiency of motion vector is promoted,the complexity of motion es timation is reduced and the quality of the reconstruction image at the same bit-rate as Multi-Reso lution Motion Estimation (MRME) is improved. 相似文献
82.
Estimation precision of Displaced Phase Center Algorithm (DPCA) is affected by the number of displaced phase center pairs, the bandwidth of transmitting signal and many other factors. Detailed analysis is made on DPCA’s estimation precision. Analysis results show that the directional vector estimation precision of DPCA is low, which will produce accumulating errors when phase cen-ters’ track is estimated. Because of this reason, DPCA suffers from accumulating errors seriously. To overcome this problem, a method combining DPCA with Sub Aperture Image Correlation (SAIC) is presented. Large synthetic aperture is divided into sub-apertures. Micro errors in sub-aperture are estimated by DPCA and compensated to raw echo data. Bulk errors between sub-apertures are esti-mated by SAIC and compensated directly to sub-aperture images. After that, sub-aperture images are directly used to generate ultimate SAS image. The method is applied to the lake-trial dataset of a 20 kHz SAS prototype system. Results show the method can successfully remove the accumulating error and produce a better SAS image. 相似文献
83.
Canhui Cai Huanqiang Zeng Sanjit K. Mitra 《Signal Processing: Image Communication》2009,24(8):630-636
Several specific features have been incorporated into Motion estimation (ME) in H.264 coding standard to improve its coding efficiency. However, they result in very high computational load. In this paper, a fast ME algorithm is proposed to reduce the computational complexity. First, a mode discriminant method is used to free the encoder from checking the small block size modes in homogeneous regions. Second, a condensed hierarchical block matching method and a spatial neighbor searching scheme are employed to find the best full-pixel motion vector. Finally, direction-based selection rule is utilized to reduce the searching range in sub-pixel ME process. Experimental results on commonly used QCIF and CIF format test sequences have shown that the proposed algorithm achieves a reduction of 88% ME process time on average, while incurring only 0.033 dB loss in PSNR and 0.50% increment on the total bit rate compared with that of exhaustive ME process, which is a default approach adopted in the JM reference software. 相似文献
84.
85.
Lookback N-time period performance options are proposed. Explicit risk-neutral probability density functions for extrema of N-time period return rates are obtained over the time interval [0, T ], T ≤? 2N. Pricing formulae at t = 0 for lookback performance options with logarithm return rate are derived. The pricing formulae for lookback performance options with gross return rate at t = 0 can be derived similarly. Put-call parity relations at t = 0 for these options follow from these pricing formulae. Applications of lookback performance options are also discussed. 相似文献
86.
We consider numerically the depinning transition in the random-field Ising model. Our analysis reveals that the three and four dimensional model displays a simple scaling behavior whereas the five dimensional scaling behavior is affected by logarithmic corrections. This suggests that d = 5 is the upper critical dimension of the depinning transition in the random-field Ising model. Furthermore, we investigate the so-called creep regime (small driving fields and temperatures) where the interface velocity is given by an Arrhenius law. 相似文献
87.
S. Iwai S. Tanaka K. Fujinuma H. Kishida H. Okamoto Y. Tokura 《Phase Transitions》2013,86(7-8):807-813
Initial dynamics of photo-induced ionic (I) to neutral (N) phase transition in tetrathiafulvalene- p -chloranil (TTF-CA) was investigated by femtosecond reflection spectroscopy with various excitation intensities. A charge transfer excitation in the I phase produces N donor (D 0 )-acceptor (A 0 ) strings within 2 ps. For a weak excitation intensity, these initial N states decay with a life time of 300 ps at 4 K, but rather multiply leading to macroscopic I-N conversion within 20 ps at 77 K just below the N-I transition temperature T NI . Near T NI , we also found the coherent motion of the macroscopic N-I domain boundary with a period of 85 ps. 相似文献
88.
We derive the motion energy dissipation model to investigate the relation between the additional energy loss of vehicles and the slope of a gradient. Simulations are carried out to check the validity of the dissipation model. Analysis of the results shows that the total energy consumption is inversely proportional to the slope in an uphill situation and the opposite conclusion can be drawn in a downhill situation. The energy dissipation rate depends on the density of traffic and the road length in two situations in a rule. It is found that the simulation result is in good agreement with real traffic. 相似文献
89.
90.
Yi-Hau Chen Tung-Chien Chen Shao-Yi Chien Yu-Wen Huang Liang-Gee Chen 《Journal of Signal Processing Systems》2008,53(3):335-347
The H.264/AVC Fractional Motion Estimation (FME) with rate-distortion constrained mode decision can improve the rate-distortion
efficiency by 2–6 dB in peak signal-to-noise ratio. However, it comes with considerable computation complexity. Acceleration
by dedicated hardware is a must for real-time applications. The main difficulty for FME hardware implementation is parallel
processing under the constraint of the sequential flow and data dependency. We analyze seven inter-correlative loops extracted
from FME procedure and provide decomposing methodologies to obtain efficient projection in hardware implementation. Two techniques,
4×4 block decomposition and efficiently vertical scheduling, are proposed to reuse data among the variable block size and
to improve the hardware utilization. Besides, advanced architectures are designed to efficiently integrate the 6-taps 2D finite
impulse response, residue generation, and 4×4 Hadamard transform into a fully pipelined architecture. This design is finally
implemented and integrated into an H.264/AVC single chip encoder that supports realtime encoding of 720×480 30fps video with
four reference frames at 81 MHz operation frequency with 405 K logic gates (41.9% area of the encoder).
相似文献
Liang-Gee ChenEmail: |