基于率失真优化和PSB系数位移的ROI编码新方法

小波系数移位和率失真优化的比率控制是实现ROI编码常用的两种策略。小波系数移位的方法能准确的恢复选择的ROI区域,但会影响编码的效率。而率失真优化的方法有好的编码效率但ROI区域重建精度受到影响。将两种机制结合,本文提出了一种率失真斜率提升和PSB系数移位相结合的ROI编码新方法。实验结果表明,新算法在同等编码效率及计算复杂度下,获得了良好的ROI重建精度。

Investigation of Combination Characteristic of Damage Location and Intensity in Arch Using Wavelet Coefficient

Arch is a typical complex structure comparing with beam and plate in bridge system. This paper investigates the damage characteristic combining the crack location with the crack intensity in arch. Initially, the first four displacement modes of intact and different damaged arch are simulated and the displacement mode changes are obtained. Next, the wavelet transformation is applied to the displacement mode changes in arch and wavelet coefficients at damage loci are picked. Finally, the damage index including damage location and damage intensity in arch is provided and plotted. The results show that wavelet coefficient module maximum of mode changes can be the damage indicator and is influenced by damage location and damage intensity. The damage indicator is proportional to the damage intensity and present monotonic trend according to damage location which depend on the mode order. At the same time, the large modulus maximum corresponds to small damage combination of location and intensity in the first four modes.