Information Entropy of Angular Spectrum for Quantitatively Evaluating Eddy Current Distribution Varying in Time Domain

Eddy current (EC) distribution induced by EC sensors determines the interaction between the defect in the testing specimen and the EC, so quantitatively evaluating EC distribution is crucial to the design of EC sensors. In this study, two indices based on the information entropy are proposed to evaluate the EC energy allocated in different directions. The EC vectors induced by a rotational field EC sensor varying in the time domain are evaluated by the proposed methods. Then, the evaluating results are analyzed by the principle of EC testing. It can be concluded that the two indices can effectively quantitatively evaluate the EC distributions varying in the time domain and are used to optimize the parameters of the rotational EC sensors.