DEMONgram Enhancement Based on Hough Transformation

Abstract

Line spectrum in DEMONgram of ship-radiated noise is a set of linear. According to this characteristics, this paper provides a enhancement technique of DEMONgram based on Hough transform for line spetrum detection. Weighting coefficient for each DEMONgram can be determined without knowing the propeller shaft frequency. It solved the problem of evaluating definition of DEMONgram. The analysis of the Sea test data shows the signal to noise ratio of propeller shaft and blade frequency are noticeably improved and line spectrum is clearer, attaining the goal of enhencing DEMONgram.