Magnetic Flux Leakage Image Enhancement using Bidimensional Empirical Mode Decomposition with Wavelet Transform Method in Oil Pipeline Nondestructive Evaluation

The magnetic flux leakage (MFL) method is the most widely used and cost-effective inspection technique for oil pipeline. However, noise is inevitable in the process of data collection; thus, the image enhancement method can be more intuitive to identify the defects in an oil pipeline MFL inspection. In this paper, the bidimensional empirical mode decomposition (BEMD) method has been used to study oil pipeline MFL images. The MFL image is decomposed into a finite number of two-dimensional intrinsic mode functions (BIMF) and a residual component by the BEMD. The wavelet transform (WT) was used to remove the noise in the BIMF. The image was then reconstructed by retaining the basic information and removing the noise. The results show that the noise is effectively removed and the detail of the MFL image is well preserved. Thus, the BEMD with WT method for oil pipeline MFL image enhancement is better than the mean filtering method and the WT method.