Reliability Tests for Demining

• Published in: E-journal of Nondestructive Testing 2006-03, Vol.11 (3)
• Main Authors: Mueller, Christina, Gaal, Mate, Pavlovic, Mato, Scharmach, Martina, Wilrich, Peter
• Format: Article
• Language: English
• ISSN: 1435-4934; 1435-4934

The total detection reliability of a mine searching system is analogous to NDE-systems governed by three elements; intrinsic capability - which describes the basic physical-technical capability of the method application factors - including those due to environment human factor - the effect of human operators on the detection reliability. Some of these can be determined in simple laboratory measurements in which the effect on detection capability of individual parameters is measured. However, the human factor and some aspects of the effects of environmental conditions on the system need to be treated statistically. By far the most common 'mine searching system' in use today is the metal detector. The test and evaluation procedures for metal detectors described in CEN CWA 14747: 2003 include the above ideas. This is why, in addition to parameter tests, they include detection reliability or blind field tests under local conditions with local personnel. A series of three field trials was performed in the ITEP-project 2.1.1.2 in 2003 'Reliability Model for Test and Evaluation of Metal Detectors' and another trial named ITEP-project 2.1.1.8 in 2005, in order to specify the optimum conditions to obtain reliable trial results with affordable effort. Each set of specific working conditions is characterized in terms of a combination of one mine type in one soil with one detector handled by local personnel. For each set of conditions, the searching system will deliver a working performance, expressed as mine detection rates as a function of mine depth, and a certain overall false alarm rate. During the ITEP-trials in Benkovac and Oberjettenberg, the authors learned to determine this function separately for each mine type in each soil. This is especially important for low-metal mines in soil that can influence metal detectors, as will be illustrated for the case of the PMA2. Two discussion points remained after 2003; how representative the trials are of field conditions and what is the statistical set-up required if we are to distinguish between the capabilities of individual detectors. In the trials of the ITEP-project 2.1.1.8 a more suitable design of experiment was applied (only two mine types in two soil types on fewer depths). The human factor was considered more carefully in applying some elements of the local SOP(Standard Operating Procedure), thus coming closer to the local practise and field conditions. Until then two detector models had been improved as a re