为了提高G3-PLC(G3-Power Line Communication)在复杂信道环境下通信的可靠性,提出了基于双正交小波变换的正交频分复用(Discrete Wavelet Transform-Orthogonal Frequency Division Multiplexing,DWT-OFDM)。通过双正交小波变换减小复...为了提高G3-PLC(G3-Power Line Communication)在复杂信道环境下通信的可靠性,提出了基于双正交小波变换的正交频分复用(Discrete Wavelet Transform-Orthogonal Frequency Division Multiplexing,DWT-OFDM)。通过双正交小波变换减小复杂信道环境下G3-PLC通信系统中OFDM载波间干扰,并通过合理减少循环前缀,优化传输效率,降低峰均比。在DWT-OFDM的G3-PLC系统中,通过不同小波基性能分析与对比,利用bior6.8双正交小波基进行系统性能优化。将DWT-OFDM的G3-PLC系统在实际电力线噪声库环境下进行实验分析,仿真结果表明,在平均误码率为10-3量级时,性能有5 dB左右提升,通信效率由40%提高至54%;结合限幅法,峰均比由11 dB降低至8 dB,通信性能极大优于基于FFT-OFDM的G3-PLC系统。展开更多
针对扫描输入纸质彩色地图噪声干扰严重,自动分割效果不理想的现状,提出了一种先去噪后分割的地图分割新方法。根据噪声性质采用维纳滤波与小波阈值萎缩相结合的去噪方法,进行基于CIE L a b 色空间的颜色聚类。与传统的彩图分割相比,该...针对扫描输入纸质彩色地图噪声干扰严重,自动分割效果不理想的现状,提出了一种先去噪后分割的地图分割新方法。根据噪声性质采用维纳滤波与小波阈值萎缩相结合的去噪方法,进行基于CIE L a b 色空间的颜色聚类。与传统的彩图分割相比,该方法对噪声具有更强的鲁棒性,处理速度快且分割清晰。展开更多
A selective subband enhancement method based on biorthogonal wavelet base is proposed. This novel image enhancement method is just for those images in which the energy of target information area is relatively lower. I...A selective subband enhancement method based on biorthogonal wavelet base is proposed. This novel image enhancement method is just for those images in which the energy of target information area is relatively lower. It includes two parts: one is enhancing the low frequency subband by wavelet decomposition and the other is building a new criterion based on entropy window to image evaluation. Experimental results show that this new scheme may result in a perfect image processing.展开更多
基金Project (2003AA1Z2610) supported by National High Technology Research and Development Programof China
文摘A selective subband enhancement method based on biorthogonal wavelet base is proposed. This novel image enhancement method is just for those images in which the energy of target information area is relatively lower. It includes two parts: one is enhancing the low frequency subband by wavelet decomposition and the other is building a new criterion based on entropy window to image evaluation. Experimental results show that this new scheme may result in a perfect image processing.
