Research On Balanced Edge Detection Methods Based On Magnetic Gradient Full Tensor Data

Edge detection is a conventional technique of potential field data processing,which is of great significance for delineating the range of abnormal bodies and dividing fault structures.However,the existing potential field edge detection methods are affected by factors such as the burial depth of the field source body,the tilt magnetization of the geological body,the external environment noise and the geological body superposition and other factors,which make the edge detection and the actual position of the geological body deviate,bringing errors and interference to the subsequent potential field data interpretation work.In order to accurately identify the actual location of geological body,this study proposes a balanced edge detection method based on the magnetic gradient full tensor data.Based on the maximum eigenvalue and the total modulus of the magnetic gradient full tensor matrix,and takes the product of the two as the new edge detection parameter,which is balanced,uses the maximum value to identify the edge of the geological body.Through theoretical analysis,model test and practical application demonstration,the following main results are obtained:(1)due to the use of the maximum eigenvalue and the total modulus of the magnetic gradient tensor matrix,the balanced edge detection method has the advantages of high resolution of tensor data and small affected by tilt magnetization of vector modulus;the product of the two further enhances the amplitude of useful signals,and improves the efficiency of shallow detection the recognition ability of geological body boundary;balancing the amplitude of deep and shallow anomalies and improve the recognition ability of deep geological body boundary by adjusting the value of balanced coefficient;because there is no derivative operation in the whole calculation process,the noise signal will not be amplified;(2)By establishing two ore bodies and four ore bodies models,considering the effects of burial depth,tilt magnetization,noise and the combination of the three,the results show that the method can identify the deep and shallow geological body boundaries simultaneously,and has high recognition accuracy,certain anti tilt magnetization ability,strong stability and the ability to distinguish different geological body boundaries under the condition of strong background field;(3)Applying the balanced edge detection method to the aeromagnetic gradient full tensor data converted from the measured aeromagnetic three-component data in an area of northern China,the obtained boundary information can basically correspond to known geological faults,which verifies the effectiveness of the practical application of the equilibrium boundary identification method,and provides a new idea for the processing of the measured aeromagnetic gradient full tensor data in the future.