用于位场场源水平边缘增强的均衡形态学滤波器

Balanced morphological filters for horizontal boundaries enhancement of the potential field sources

位场场源水平边缘的增强对于地质构造研究具有重要意义。现有用于源水平边缘增强的滤波器多数基于位场数据的导数构建,但这些滤波器常表现出一些不足,如输出边缘发散、无法均衡强弱异常或结果中存在额外虚假边缘等。本文通过数学形态学基本算子的组合叠加,首先定义了基于数学形态学的边缘增强滤波器MMA,为了使该滤波器具备均衡不同振幅异常的能力,提出了MMAZ和MMAT滤波器,通过二者的极大值位置均可实现对位场场源边缘的圈定。合成数据试验结果表明,MMAZ和MMAT滤波器具有很好的均衡能力和抗噪性能,同时相比传统几种滤波器,根据这两种滤波器获得的地质体水平边缘更加清晰收敛,而且针对包含正负异常的地质情况,输出结果中没有额外边缘的产生。最后将这两种新的均衡滤波器应用到老挝万象盆地某钾盐矿区的重力异常和中国西北某金属矿区航磁异常数据的处理中,获得的构造线位置更加准确清晰,从而进一步说明了这两种滤波技术的有效性。

The enhancement of horizontal boundaries of potential field sources is of great significance for the study of geological structures.Most of the existing filters for horizontal edges enhancement are presented based on the derivatives of potential field data,but these filters often show some shortcomings,for example,the output edges are divergent,strong and weak anomalies cannot be balanced,or some extra false edges appear in the results.In this paper,the edges enhancement filter MMA based on mathematical morphology is first defined by the combination of the basic operators of mathematical morphology.In order to make the filter have the ability to balance different amplitude anomalies,MMAZ and MMAT are proposed,and both of them can be used to delineate the horizontal edges of the field sources by their maxima.The experimental results of synthetic data show that MMAZ and MMAT have good equalization and anti-noise performances.Compared with several traditional filters,the horizontal edges of geological bodies obtained by these two filters are clearer and more convergent,and there are no extra edges in the output results for the complex situations that positive and negative anomalies exist simultaneously.Finally,the two new equalization filters are applied to gravity anomaly data in a potash mine area in Vientiane basin of Laos and the aeromagnetic anomaly of a metal mine in northwest China,the obtained positions of the structures are more accurate and clearer,which further illustrates the effectiveness of the two filtering techniques.