The performance of mine detecting instruments is embedded in the behavior of a complex system. The total reliability is always composed of the intrinsic physical detection capability of the sensor, application/environmental influences and human factors. The intrinsic capability and some application factors can be investigated in laboratory measurements. Human factors, other application factors and the overall reliability, can only be evaluated in blind field trials in which the probability of detection (PoD) and false alarm rate (FAR) are measured statistically. Both of these approaches are included in CEN Workshop Agreement CWA 14747:2003, which standardizes detector testing in Humanitarian Demining. We report here the results of a study to investigate how to optimize such testing. For efficient and statistically valid field trials, the number, types and burial depths of targets, and the number of test lanes, soil types, repetitions and operators need to be carefully chosen. Laboratory results should be used to help construct field trial protocols and also to help distinguish the different contributions to the PoD and FAR, to determine where to improve insufficient performance. In this study, four models of metal detector were tested in three field trials and in the laboratory. The repeatability of the field trials is assessed, taking into account operator training and experience. Results of the laboratory tests are compared with results of the field trials and used to construct a "modular model" of the system, as used in nondestructive testing. The conclusions are, in principle, applicable to trials of other types of sensor.
The MsMs project is a major campaign to collect calibrated and well-documented data, suitable for use by workers developing advanced multisensor algorithms for antipersonnel mine detection. The data, together with a full description of the site layout and measurement protocols, are publicly available via the internet site http://demining.jrc.it/msms. Measurements are made on a test lane consisting of 7 plots of different soils, each 6m by 6m, populated with surrogate mines, calibration objects, simulated clutter and position markers. There are 48 targets in each plot, configured identically for all plots. A first report was presented last year. Since then, laser acoustic vibrometer and magnetometer data have been added and the metal detector and thermal infrared data have been augmented. The database has been reformatted to make it more uniform and user-friendly and to remove typographic mistakes. The test site remains essentially unchanged, apart from some equipment upgrades, and is available for further data collection. In particular, the targets have not been moved, so as to provide stable surrounding soil conditions representative of mines left undisturbed for long periods post-conflict. This presentation will describe the new data and data format, the status of the upgrades and the outlook for the future.