关键词: 稀疏表示, 字典学习, 滚动轴承, 最优方向法（MOD）

Abstract: Rolling bearing vibration signal’s sparse representation over over-complete dictionary is a hot issue. In this paper, it proposes an improved method for MOD（Method of Optimal Direction） dictionary learning, which is applied to sparse representation of rolling bearing vibration signal. The core of this method is processing of dictionary learning, which is carefully constructed. In this processing, data is segmented with overlapping. In comparison with DCT, FFT and normal method, the transform coefficient is sparser, which is obtained by improved method. This method is applied in vibration signals processing based on compressed sensing. Compared with DCT and FFT in the same range of reconstruction error, the method requires less measure data, and less computational.

Key words: sparse representation, dictionary learning, rolling bearing, Method of Optimal Direction（MOD）