重力异常图中的边界增强和提取技术

对比了重磁勘探领域中4种典型的边界增强方法：Tilt导数、Tilt导数的水平梯度、Theta角和归一化的标准偏差，它们都能放大与边界有关的高频异常。增强后异常幅值极大值与地质体边界对应的情况可用近似边界法自动提取，而异常幅值拐点与边界对应的情况可以引入Canny边界检测算子来提取。理论模型试验表明：用Canny算子提取Tilt导数图边界与用近似边界检测法提取其它边界增强图的边界相比，前者提取的边界位置与真实位置更吻合，虚假边界更少。应用该方法对梅山铁矿的局部重力异常进行了处理，勾画出铁矿的大致范围。

Edge Enhancement and Detection Technology in Gravity Anomaly Map

Four classical edge enhancing methods in gravity and magnetic exploration field are compared: Tilt derivative, horizontal gradient of Tilt derivative, Theta angle and normalized standard deviations. All of them can amplify high frequency anomalies related to edges. An  approximate edge detector can be used in enhanced contour maps where local maximum relates to geology edge. While Canny edge detector can deal with enhanced map where inflexions relate to geology edge. Module tests in theory show that, comparing Canny edge detector for Tilt gradient map with approximating edge detector for other edge enhance map, the edge positions detected with the former accord with the real positions more accurately and there are fewer fake edges. In the applications, use is made of this method to deal with the local gravity of Meishan iron ore and to help approximately locate the boundary of iron bodies.