提出了一种自动提取地球物理位场水平一阶导数图象中局部极大（极小）值线的有效方法。该方法的基本原理是，首先用方向剖面法识别出地球物理位场水平一阶导数图象中的局部极大（极小）值点；然后，用旋转变换方法搜索出各个方向展布的局部极大（极小）值线的端点；最后，根据极值线共线和钝角相交的合并规则将极值线合并成折线，并删除过短的极值线，从面时球物理位场水平一阶导数局部极值线的矢量图。用山东半岛航磁图做试验，自动提取结果与目视解译结果基本吻合，从而证明了方法的有效性。

In this paper, a new approach for automatic extracting the local maximum(or local minimum) lines from the first horizontal derivative images of geophysical fields is proposed. The basic procedure of this method is as follows: First, the directional profile method is applied to recognizing local maximum (or local minimum) pixels from the field images. Then, the rotation transformation method is applied to searching maximum (or minimum) line endpoints in all directions. Finally, a vector map for the local extreme lines of the first horizontal derivative images of geophysical fields is obtained through that, the closely spaced lines are merged into broken lines in line with the line merged regulations, and that all of short lines are eliminated. The aeromagnetic map of Shandong peninsula was served as the experimental image. The experimental results showed that the local extreme lines both extracted automatically and interpreted manually are basically identical. It proved that the method is effective.