I. Introduction
Signals have more or less noise in the process of generation or transmission. Therefore, filtering algorithm has always been the most basic and important data preprocessing tool, and it has been an enduring research topic. Filtering algorithms can be roughly divided into two categories, local-based filtering and global-based filtering. In general, the filtering effect of the global-based filtering algorithm is better than that of the local-based filtering algorithm. However, compared with local-based filtering algorithms, its computational complexity is high. Moreover, the real-time performance of the algorithm has always been an important indicator to measure the pros and cons of the algorithm, and the performance of the current local-based filtering algorithm is getting closer and closer to the global-based filtering algorithm. Therefore, local-based filtering algorithms are increasingly favored by researchers and users.