Two video coding schemes based on wavelet transform achieving very low bit rate are presented in this paper. The first is a hybrid motion compensated wavelet transform(MC WT)system which behaves better at very low ...Two video coding schemes based on wavelet transform achieving very low bit rate are presented in this paper. The first is a hybrid motion compensated wavelet transform(MC WT)system which behaves better at very low bit rates than the block DCT residual coder. The second is a new efficient coding system based on a simple frame differencing wavelet transform(FD WT)which performs well in both PSNR and visual quality with substantially reduced complexity.展开更多
A new improved Goh's 3 D wavelet transform(WT) coding scheme is presented in this paper. The new scheme has great advantages including a simple code structure, low computation cost and good performance in PSNR, c...A new improved Goh's 3 D wavelet transform(WT) coding scheme is presented in this paper. The new scheme has great advantages including a simple code structure, low computation cost and good performance in PSNR, compression ratios and visual quality of reconstructions, when compared to the other existing 3 D WT coding methods and the 2 D WT based coding methods. The new 3 D WT coding scheme is suitable for very low bit rate video coding.展开更多
Block matching motion estimation techniques have been widely used in video coding applications. However, they also show their deficiency in the coherence of motion vectors and antinoise ability. This paper proposes a...Block matching motion estimation techniques have been widely used in video coding applications. However, they also show their deficiency in the coherence of motion vectors and antinoise ability. This paper proposes a modified algorithm which can adopt any one of existing search algorithms and pays more attention to the correlation of neighboring blocks.It will be shown that the proposed algorithm is simple and significantly reduces the computational complexity. Simulation results also show that this algorithm improves the smoothness of the motion field, hence reducing the cost to code the motion vectors while keeping good performance comparable with the conventional block matching motion estimation algorithm.展开更多
针对油茶挖坑机具工作过程中出土率低下、土壤回流量大、人工二次清土工作繁杂等问题,依照现有油茶挖坑机具的结构,利用离散元法仿真软件(Engineering discrete element method,EDEM)仿真及试验研究,优化机具参数提高挖坑出土率。以适...针对油茶挖坑机具工作过程中出土率低下、土壤回流量大、人工二次清土工作繁杂等问题,依照现有油茶挖坑机具的结构,利用离散元法仿真软件(Engineering discrete element method,EDEM)仿真及试验研究,优化机具参数提高挖坑出土率。以适用于丘陵山地复杂立地环境的大直径挖坑钻头为研究对象,提出油茶大直径钻孔技术方案,设计一款大直径钻孔、高出土率的钻头。对挖坑钻头主要部件建模并结合EDEM2023软件对土壤建模,同时对机具挖坑工作过程进行仿真。以钻孔装置出土率高低为评价指标,以钻杆直径、螺旋升角、土壤与翼片静摩擦因数为试验因素,进行单因素试验确定3个参数的取值范围;以此为基础进行多因素正交试验从而确定出土率最佳的参数组合。单因素试验结果表明,钻孔装置钻杆直径从80 mm增大至120 mm,出土率呈现下降趋势;翼片螺旋升角由15°增大至23°,出土率呈现下降趋势;土壤与翼片的静摩擦系数由0.50增大至0.60,出土率呈现先增后减趋势。在三者中,螺旋升角对出土率影响最大,钻杆直径对出土率影响最小。二次回归正交旋转组合试验结果表明,三因素对挖坑机具出土率的影响由大到小的顺序为螺旋升角、静摩擦系数、钻杆直径,最佳方案是钻杆直径为82 mm、螺旋升角为23°、静摩擦因数为0.56,这3个参数组合下出土率为92.73%。展开更多
近年来,超宽带(Ultra-wideband,UWB)通信技术因其具有数据传输速率高、功耗低、保密性高、成本低等诸多优点,成为室内高速数据传输的一种有效解决方案。由于高速通信下码间串扰极大地影响了UWB系统的接收性能,需要在解调前采用Rake接收...近年来,超宽带(Ultra-wideband,UWB)通信技术因其具有数据传输速率高、功耗低、保密性高、成本低等诸多优点,成为室内高速数据传输的一种有效解决方案。由于高速通信下码间串扰极大地影响了UWB系统的接收性能,需要在解调前采用Rake接收机和均衡等手段消除码间串扰。针对自适应最小误码率(Adaptive Minimum Bit Error Rate,AMBER)均衡算法与Rake接收机结合进行研究,提出了一种变步长自适应最小误码率(Variable Step-Adaptive Minimum Bit Error Rate,VS-AMBER)均衡算法,在较低信噪比和较高信噪比情况下分别使用不同的变步长方案,较高信噪比下在收敛速度和收敛精度上有所提升,较低信噪比下降低了误码率和功耗。展开更多
文摘Two video coding schemes based on wavelet transform achieving very low bit rate are presented in this paper. The first is a hybrid motion compensated wavelet transform(MC WT)system which behaves better at very low bit rates than the block DCT residual coder. The second is a new efficient coding system based on a simple frame differencing wavelet transform(FD WT)which performs well in both PSNR and visual quality with substantially reduced complexity.
文摘A new improved Goh's 3 D wavelet transform(WT) coding scheme is presented in this paper. The new scheme has great advantages including a simple code structure, low computation cost and good performance in PSNR, compression ratios and visual quality of reconstructions, when compared to the other existing 3 D WT coding methods and the 2 D WT based coding methods. The new 3 D WT coding scheme is suitable for very low bit rate video coding.
文摘Block matching motion estimation techniques have been widely used in video coding applications. However, they also show their deficiency in the coherence of motion vectors and antinoise ability. This paper proposes a modified algorithm which can adopt any one of existing search algorithms and pays more attention to the correlation of neighboring blocks.It will be shown that the proposed algorithm is simple and significantly reduces the computational complexity. Simulation results also show that this algorithm improves the smoothness of the motion field, hence reducing the cost to code the motion vectors while keeping good performance comparable with the conventional block matching motion estimation algorithm.
文摘近年来,超宽带(Ultra-wideband,UWB)通信技术因其具有数据传输速率高、功耗低、保密性高、成本低等诸多优点,成为室内高速数据传输的一种有效解决方案。由于高速通信下码间串扰极大地影响了UWB系统的接收性能,需要在解调前采用Rake接收机和均衡等手段消除码间串扰。针对自适应最小误码率(Adaptive Minimum Bit Error Rate,AMBER)均衡算法与Rake接收机结合进行研究,提出了一种变步长自适应最小误码率(Variable Step-Adaptive Minimum Bit Error Rate,VS-AMBER)均衡算法,在较低信噪比和较高信噪比情况下分别使用不同的变步长方案,较高信噪比下在收敛速度和收敛精度上有所提升,较低信噪比下降低了误码率和功耗。
