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

联合国（UN）宣布，“恐怖主义是一种全球性威胁，需要对来自全球100多个国家的3万多名外国恐怖分子作出全面和统一的反应。”在此之前，最近发生了一系列恐怖袭击，包括法国和德国的袭击（2016年7月），西方世界的全球不确定性日益增强。促进对金属威胁物品的识别和定位的改进是统一响应的一个重要方面，也是一个工程和科学可以产生重大影响的领域。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利益。将技术转让给开发用于安全结构材料的无损检测（NDT）设备、确保食品安全、改进废金属分拣以及用于医学成像和考古搜索的MD公司，将带来更广泛的好处。当然，目前的金属探测器确实可以发现高导电性物体，它们简单的设计（和便携性）使它们成为安全和安保应用的一种极具成本效益的方式。不幸的是，目前的技术无法（或能力有限）区分不同形状的物体和物体的材料，只能探测到一个小的距离（或埋深）内的物体。本提案旨在通过跨学科的方法，结合工程、数学和科学计算来改进MD技术，以克服这些缺点。我们的假设是，金属物体在低频电磁场中的响应可以用基于张量的近似精确地描述。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。这包括以下新方面：一种高效且适应性强的软件，可以计算非均匀物体的张量系数，一种通过嵌入式不确定性量化从现场测量中识别不同目标的算法，以及通过基于优化线圈设计构建新的线圈阵列来增强MD测量。我们的目标是，我们完整的软件和测量包将导致MD的一个步骤变化。

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.