Methods for improving the stability of electromagnetic geophysical inversions

Two methods are presented for improving the stability of geophysical inversions. The first method uses the weighted-least-squares technique to reduce the effects of additive noise in the measurement data. This is accomplished by giving a lesser weight to those measurements that are thought to be more noisy. Some simulations are presented that demonstrate the effectiveness of this method. In addition, the authors explore the possibility of using postreconstruction image processing to reduce the effects of noise in the measurements. A novel technique, referred to as minimax partitioning, is developed. This method, in conjunction with image filtering is used to locate high-contrast anomalies in a region. Examples are presented that show the superiority of this partitioning scheme over other techniques.<>