{'fraction_non_alphanumeric': 0.026874115983026876, 'fraction_numerical': 0.0, 'mean_word_length': 5.206140350877193, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Passive Millimeter-Wave Imaging for the Detection of Concealed Weapons

Abstract : The passive millimeter-wave camera (PMC) is a second generation millimeter-wave (MMW) imaging system delivered to the National Institute of Justice for evaluation as a concealed weapons detection system. The PMC uses an unusual pupil-plane architecture as opposed to the focal plane architecture common in other MMW systems. A frequency-scanned phased-array antenna paired with a number of quasi-optical MMW processing boards allows the system to create a wide field-of-view video rate image while using a relatively small number of MMW amplifiers. The system also occupies a small volume compared to focal-plane based systems. This paper details the components that make up the imager, including the flat-panel antenna, MMW amplifiers, processor boards, diode detectors, digital read-out circuits, and MMW transitions. The paper also describes the construction of these devices and the integration of the PMC system. Integration includes phasing the system front-end, setting back-end power levels, and building and testing frequency processor board arrays. The PMC imager has problems with feedback into the antenna and calibration drift, but the system was tested for performance, including angular resolution and temperature sensitivity. The test procedures are discussed here and the test results are attached to the document.