Firstly, SP supposed to be generated by point curl source which is the border of dipole layer rather than the line dipole layer in section view, then, curl source scanning function is given, and image is retrieved by probability tomography approach.

• 首先把剖面上偶极层的线分布产生的场看作是偶极层的边缘－旋度源的点分布产生的场；然后给出旋度源的扫描函数，用概率成像方法对旋度源进行成像。