Rapid Airport Security Screening Using Superconducting Technology - RASSUST

目前，机场安检通常包括全身扫描，英国的新规定将要求到2022年，所有飞机乘客在登机前都要接受全身扫描，这是标准安检程序的一部分。这种扫描仪的工作原理是在人眼不可见的颜色下观察人体。这些颜色出现在所谓的毫米波长，在大多数情况下，这种颜色的光产生的方式与我们人类看到的光学光一样——热。大多数衣服对毫米波长的光是透明的，而许多可能构成安全风险的物体却不是。我们身体的热量是毫米光的自然来源，隐藏在衣服下的物体可以阻挡这种光线，从而产生物体的阴影。然而，毫米波光很难探测，需要特殊的相机。到目前为止，机场的技术还不够灵敏，无法测量人体热量产生的自然毫米波光，而是用毫米波光照亮每个人，并测量反射。这类似于在暗室里拍照时使用闪光灯。这个过程是缓慢的，并且需要每个人在拍摄图像时保持静止。以这种方式对每个人进行成像大约需要15-20秒，由于系统的不灵敏度，通常需要额外的手动搜索。如果要求所有乘客都以这种方式进行安检，机场安检协议的时间和成本将不可避免地增加。利用最初为天文学开发的技术，我们提出了一个解决这个问题的方法。我们已经开发了一种基于超导探测器的毫米波摄像机，当一个人简单地走过摄像机时，它能够执行所需的安全成像。在大多数情况下，这个人不会意识到这个系统，就像我们在机场对闭路电视不知情一样。这项技术的关键是超灵敏的毫米波探测器，它不需要当前扫描仪使用的“闪光灯”，可以在视频模式下工作。探测器通过在极低的温度下工作来获得灵敏度，事实上，只比绝对零度高几度——这是物理上可能达到的最冷的温度。在繁忙的机场安装这样的摄像头似乎是不可能的，但现代技术使达到这样的温度成为常态。为了证明这一点，2018年11月，我们的团队将毫米波相机的通用版本带到卡迪夫机场，在那里我们在典型的机场环境中进行了多次成功的成像试验。我们的系统能够很容易地检测到隐藏在厚外套下的假枪，甚至与人工智能系统一起被证明可以识别和突出这个被禁止的物体。这种图像自然会引起人们对隐私和安全的担忧。在我们的系统中，被筛选者的形象以保持谦虚的轮廓出现。此外，由于不需要照明，我们的系统完全是被动的，就像给被扫描的人拍一张普通的照片或视频一样。该项目将解决阻碍这项新技术商业应用的几个问题。我们希望调整我们的通用摄像机，使其能够24小时自动操作，并能够从四个视点对一个人进行成像，从而在一个人走过时进行安全扫描。我们还将开发新的探测器阵列，以提高探测潜在隐藏威胁的灵敏度。我们还将开发新的电子设备，以降低我们系统的总体成本，同时提高性能，以应对现代机场快速检查的挑战。总体目标是生产一种比目前使用的技术更便宜、更快、更方便、更安全的全身扫描仪。

Security at airports now commonly involves full body scanners and new regulations in the UK will require all air-passengers to undergo a full body scan by 2022 as part of the standard security process before boarding an aircraft. Such scanners work by viewing the body at colours not visible to the human eye. These colours occur at so called millimetre wavelengths and in most cases light at this colour in generated in the same way as the optical light we see as humans - heat. Most clothing is transparent to light at millimetre wavelengths whereas many objects that could pose a security risk are not. The heat from our body is a natural source of millimetre light and objects hidden under clothing can block this light from view creating a shadow of the object. However, millimetre wave light is difficult to detect and requires special cameras. The technology in airports to date is not sensitive enough to measure the natural millimetre wave light produced by our body heat but instead illuminates each person with millimetre wave light and measures reflections. This is similar to using a flash on a camera when taking a photograph in a dark room. This process is slow and requires each person to be stationary while the image is taken. Each person takes around 15-20 seconds to be imaged in this way and due to the insensitivity of the system an additional manual search is often required. Moving to a requirement where 100% of passengers are screened in this manner, an increase in the time and cost of security protocols at airports are inevitable. Using technology originally developed for astronomy, we propose a solution to this problem. We have developed a millimetre wave camera based on superconducting detectors that has the capability of performing the required security imaging while a person simply walks past the camera. In most cases the person would be unaware of this system in the same way we have become unconscious to CCTV at airports. The key to this technology are ultra-sensitive millimetre wave detectors that do not require the "flash" used in current scanners and can work in video mode. The detectors gain their sensitivity by working at extremely low temperatures, in fact, only a fraction of a degree above absolute zero - the coldest temperature physically possible. Realising such a camera in a busy airport may seem impossible but modern technology makes reaching such temperatures routine. To prove this, in November 2018, our group took a generic version of our millimetre-wave camera to Cardiff airport where we conducted a number of successful trials imaging people in a typical airport environment. Our system was able to easily detect a mock gun concealed under a thick coat and was even proven in conjunction with artificial intelligence systems that could recognise and highlight this forbidden object. Such imaging naturally raises concerns regarding privacy and safety. In our system, the image of the person being screened shows up as a silhouette preserving modesty. Furthermore, with no requirement for illumination, our system is completely passive making it the same as taking a normal photograph or video of the person being screened. This project will address several issues preventing the commercial adoption of this new technology. We wish to adapt our generic camera to enable 24-hour automated operation as well as the ability to image a person from four viewpoints creating a compete security scan as a person walks past. We will also develop new detector arrays providing improved sensitivity to detecting potential concealed threats. We will also develop new electronics that will reduce the overall cost of our system while enhancing performance to meet the challenges of rapid screening in a modern airport. The overall aim is to produce a full body scanner that is, cheaper, faster, more convenient and overall safer than the technology currently used.