An improved tilt angle filter for potential field data

Abstract

The tilt angle, T, is a useful filter for enhancing subtle anomalies in potential field data. It is formed from the ratio, R, of the vertical derivative to the total horizontal derivative of the field (Equation 1). Because this ratio has a long-tailed distribution that can take on any value from −∞ to +∞, which is difficult to image satisfactorily, the range of values are compressed to ±π/2 using the arctan function. However there is nothing special about this function, and this paper suggests that a data-adaptive mapping of the histogram of the ratio to an equalized or a Gaussian distribution can give superior results.