关键词: 双密度小波变换, 双变量收缩函数, 电能质量信号, 信噪比

Abstract: In order to improve the quality of the de-noised power quality signal, an efficient adaptive power quality signal de-noising algorithm based on the Double-Density Discrete Wavelet Transform（DD DWT） is proposed. DD DWT has approximately shift invariance and can accurately describe the real characteristics of signals. Meanwhile, the Bivariate Shrinkage Function（BSF） considers the relationship of the inter-level and intra-level coefficients. So, BSF with local variance estimation is adopted to processing wavelet coefficients. Then the signals are synthesized using the wavelet coefficients processed. The experimental results indicate that, the proposed algorithm can remove the noise more efficiently and keep original power quality signal characters, and that the visual quality of the denoised signal is improved.

Key words: Double-Density Discrete Wavelet Transform（DD DWT）, Bivariate Shrinkage Function（BSF）, power quality signal, Signal Noise Rotio（SNR）