DESIGN AND ANALYSIS OF MATHEMATICAL MORPHOLOGY-BASED DIGITAL FILTERS

With respect to different types of the interference possibly encountered in power signal monitoring, detailed investigations are carried out through numerical simulation, regarding the impacts of the shape, amplitude and width of a structure element on the performance of mathematical morphology-based digital filters. The analysis indicates that, the selection of an optimal structure element is very much dependent on the type and frequency of the interference as well as the sampling rate of the data series to be processed, and should normally be pre-determined by numerical simulation based on the concrete features of both the signal and its interference. For an effective elimination of the wide-band interference, a structure element of cosine type should be preferably applied to obtain satisfying filter performance. But for the narrow-band interference, a rectangular structure element shows good behaviors in applications. Also, the width of a structure element should be chosen proportionally to the increase of the sampling rate to achieve optimal filtering characteristics. These research results present useful design references for the application of the mathematical morphology-based filters in power signal monitoring and processing.