Finite element analysis approach to open area concealed weapon detection system

Individuals carrying threat objects inside secured areas possess significant risk to security of establishments and safety of public. Traditional weapon inspection equipment is limited in portability and requires trained operators in confined security checkpoints. Although various methods to screen people for threat objects have been employed at secured establishments, screening equipment and procedures have not been designed to work in open spaces like airport check-in areas, hospitals, schools and university entrances. Coupled to this, relatively large numbers of false alarms from non-threat metal objects are identified as a threat by the current Concealed Weapon Detection (CWD) screening equipment, is a major cause of concern and is associated with higher operational costs. Hence, the design and development of a concealed weapon detection system, with reduced false alarms and increased detection along with classification capability that can operate in a large open area is essential. \nA comprehensive numerical model of a CWD system, using the Finite Element Analysis (FEA) method, to detect and classify metal objects with accuracy within a single zone of a multi zone Open Area CWD (OACWD) system, was developed. A mathematical model was developed and applied to the time-domain transient electromagnetic field, which are modelled and simulated using FEA methods. The methods were then applied to a single zone of a multi zone OACWD system to create an object signature database utilising the decay time constant; a unique property of metal objects in time-domain transient electromagnetic fields. The objects were detected by the unique signature property in OACWD system, Since early and intermediate stages was found contain object signatures, receiver current for these stages are digitised and stored in a weapon database, which is then used to match target for identification within the OACWD system. The thesis analyses the following characteristics of a single zone OACWD system; target material variation, target shape (both geometric and common weapon shape) variation, size, rotational variation, proximity variation of targets, the successful estimation and comparison of these parameters lead to classification of metal objects in OACWD system. This work also explores the characteristic properties and components of OACWD models such aspublic safety and the privacy of individuals using the system. The system, when integrated with other screening devices, e.g. Close Circuit Television (CCTV) monitoring system, is able to find individuals with threat objects in real-time detection space. \nSummarizing, In this thesis work, single zone detection system was designed by developing have developed an electromagnetic circuit to design, which can successfully detect threat metal objects irrespective of their orientation based on time constant decay. This system is a significant advance over the existing portal based detection system, as it would reduce the incidence of false alarms and traffic congestion at the security establishment.