Fault Feature Extraction Method of Time-Frequency Image Based on Fractal Dimension

摘要

A fault feature extraction method of time-frequency image based on fractal dimension is put forward in this paper. Theoretical calculation formulas of fractal dimension are introduced and the calculation method about box-counting dimension based on image processing is analyzed. Based on this, the vibration signals measured from diesel engine in the stage of deflagration are researched with smooth slice Wigner higher order moment spectrums. Then the dimensions of fractal images which were obtained from the signal waves and the Wigner higher order moment spectrums are calculated by the fractal dimension calculation program. The result indicates that different wearing stages of piston-cylinder can be discriminated depending on feature parameters of fractal dimension because the fractal dimensions of images are apparently different.