Reduction to the pole of magnetic anomalies based on discrete cosine transform
基于离散余弦变换（DCT）的化磁极方法

In order to improve the calculating quality on reduction to the pole (RTP) of magnetic anomalies, the paper propose a method of RTP based on the discrete cosine transform (DCT). We deduce theoretical formulas conversion of RTP of the total field anomalies for two and three dimensional bodies according to the cosine transform spectra analysis of the potential field in theory. There is high precision in the model experiment of sloping plate and the RTP field errors are less than 0.001 nT. In the model experiments of single and multi-sphere, we can obtain the better RTP results using the DCT method when the magnetic dip is 5°, and the results are excellent when the dip is 15°.The shape of contour line, the maximum and the plane location of magnetic model are all good comparing with the theoretical anomalies when the model is perpendicular magnetization.