Preprocessed Method and Application of Magnetic Gradient Tensor Data

The edge detection method is significant in the interpretation of magnetic data, and can effectively identify the edge of the magnetic source. In this paper, a new edge detection method of magnetic sources is proposed under the oblique magnetization condition. First, the data of the magnetic field component is transformed into the total magnitude anomaly and its direction cosinesaccording to the inter-relationship between different magnetic field components. To eliminate noise, we use the K-Singular Value Decomposition denoising method based on the mean signal improvement to reconstruct the magnetic signal. Then, the three components of the magnetic field data is converted into the data of three components from the same magnetic source under the vertical magnetization condition by using the calculated magnetization direction of the magnetic source. Finally, the edge of the magnetic source is calculated through the ratio of the magnetic gradient tensor invariant to the B_zz component data under the vertical magnetization condition. This method is verified by simulation and experiment. The simulation and experimental results obtained show that this method considerably reduces the effects of the oblique magnetization. Besides, the method in this paper has high noise immunity.