Split-threshold hit/miss transform for mines

A modification to the hit/miss transform which has been developed to aid in the automatic detection of mines in sonar data is described. This modification allows the input thresholds for the data fed to the hit and the miss sections of the transform to be independently controlled. This makes it possible to have a high input threshold for the hit filter (this allows only high detections through) and a lower input threshold for the miss filter (this avoids splitting large but not as bright regions and thus reduces false alarms). The false alarms of particular interest are sand ridges and drag lines which must remain contiguous for the miss filter to properly exclude them. The modified hit/miss transform when fused with a matched filter has a similar detection rate and significantly lower false alarm rate when compared to the system which is presently in the field consisting of the matched filter fused with a neural network and a statistical analysis.