Reducing the Threat to Public Safety: Improved metallic object characterisation, location and detection

联合国在一份声明中说：“来自世界各地约100个国家的30，000多名外国恐怖主义战斗人员，恐怖主义是一个全球性威胁，需要全面和统一的反应。“这一声明是在最近一系列恐怖袭击之后发表的，包括法国和德国（2016年7月）的恐怖袭击，以及西方世界日益增长的全球不确定感。促进改进金属威胁物项的识别和定位是统一应对的一个重要方面，也是工程和科学可以产生重大影响的一个领域。金属探测技术的改进也为发展中国家清除地雷的人道主义事业提供了更广泛的好处。更广泛的好处存在的技术转让给MD公司开发设备的非破坏性测试（NDT）的材料安全结构，确保食品安全，改善废金属分拣，当然，目前的金属探测器确实能发现高导电性的物体和它们简单的设计（和便携性）使它们成为用于安全和安保应用的高度成本效益的模式。然而，现有技术无法区分不同形状和材料的物体，只能探测到小间距（或埋深）内的物体，本研究旨在通过工程、数学和科学计算相结合的多学科方法来改进MD技术，以克服这些缺陷。我们的假设是，金属物品在低频电磁场中的响应可以使用基于张量的近似来准确地描述。为了验证这一假设，我们将开发一个完整的实验室演示我们的MD方法。这包括以下新的方面：一个有效的和适应性强的软件，可以计算张量系数的不均匀的对象，一种算法，用于识别不同的目标，从现场测量与嵌入式不确定性量化，以及增强MD测量通过构建新的线圈阵列的基础上优化线圈设计。我们的目标是，我们完整的软件和测量包将导致MD的一步变化。

The United Nations (UN) have announced that "With more than 30,000 foreign terrorist fighters from some 100 countries around the world, terrorism is a global threat requiring a comprehensive and unified response." This statement followed a spate of recent terrorist attacks, including those in France and Germany (July 2016), and a growing sense of global uncertainty in the western world. Promoting improvements to the identification and location of metallic threat items is an important aspect of the unified response and is an area where engineering and science can make a significant impact. Improvements in metal detection (MD) technology also provides wider benefits to the humanitarian cause of clearing landmines in developing countries. Wider benefits exist for the technology being transferred to MD companies developing devices for the non-destructive testing (NDT) of materials for safe structures, ensuring food safety, improved scrap metal sorting, as well as in medical imaging and archaeological searches.Of course current metal detectors do find highly conductive objects and their simple design (and portability) has made them a highly cost effective modality for safety and security applications. Unfortunately, current technology is not able (or has limited capability) to distinguish between objects of different shape and materials of objects and can only detect objects within a small stand-off distance (or buried depth).This proposal is aimed at overcoming these drawbacks through an interdisciplinary approach to improving MD technology, combing engineering, mathematics and scientific computation. Our hypothesis is that the response of metallic items in low frequency electromagnetic fields can be accurately described using a tensor based approximation. To test this hypothesis, we will develop a complete laboratory demonstration of our MD approach. This includes the following novel aspects: an efficient and adaptable software that can compute tensor coefficients for in-homogeneous objects, an algorithm for identifying different targets from field measurements with embedded uncertainty quantification as well as enhancing MD measurements by building new coil arrays based on optimised coil design. The goal is that our complete software and measurement package will lead to a step change in MD.