Year
2014
Abstract
Video surveillance cameras used for safeguards applications have grown progressively more sophisticated and costly. It would not be prudent to deploy such high-value equipment directly in high radiation areas, contamination areas, confined spaces, or other harsh environments. International nuclear material safeguards could easily desire video surveillance of activity within hot cells, spent fuel shearing operations for reprocessing, or in storage facilities. Camera performance and life could be compromised; moreover, the camera would be difficult to maintain and service. We consider instead a practical means to deploy a high-value safeguards camera some distance removed from the scene of interest. Video surveillance would still be possible if an image could be piped to the camera. Likely an image pipe will incorporate shielding windows and/or offset paths using mirrors to penetrate a shield wall. Practical implementations will differ from case to case, but in this work we pose a generalized application scenario. The scenario simplifies the problem for the purpose of determining requirements, developing an approach, and eventually demonstrating a feasible solution for “standoff” video surveillance. The three primary technical challenges for standoff video are (1) devising an optical architecture for relaying images from the scene of interest to the camera, (2) ensuring the authenticity of those images, and (3) ensuring that optical components closest to the scene are “radiation hard.” For the first problem, various transparent optical-quality plastic light guides and/or fiber bundles might be considered, but these can fail in radiation environments. In our baseline scenario, we instead replace the camera objective lens with a relay lens system that transmits images over a straight path in air. The camera sensor and the surveillance objective lens are arbitrarily chosen to be two meters apart. The second problem recognizes that digital authentication at the camera’s image sensor is insufficient; that the extended optical path is vulnerable to tamper. We therefore devise a means to test authentication approaches to ensure the image integrity through the extended surveillance system. Eventually we will evaluate the front-end optical components and in-scene authentication devices for radiation hardness, but that is beyond the scope of this paper.