Application of morphological operations in spectrum segmentation process for direction finding

The modern direction finders (DF) are able to process the frequency band that is much wider than usual signal spectrum. Therefore, as several radio transmitters can be active in the observed frequency range, a further assessment of the active transmitter number as well as their parameters is needed. This additional processing is labeled as spectrum segmentation or preclassification. This paper discusses the possible pre-classification process improvement by using the morphological operations: erosion and dilation. For different types of radio-emissions, the results of conducted analysis of morphological operation application with the use of various structural elements is given. The main contribution of here presented work is the experimental confirmation that the proposed morphological image processing can improve the accuracy of the spectrum segmentation and that this accuracy depends on the choice of structural elements.