{'fraction_non_alphanumeric': 0.014367816091954023, 'fraction_numerical': 0.01293103448275862, 'mean_word_length': 5.453703703703703, '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}}
Night Vision Goggle External Lighting Effects

The National Research Council of Canada, Transport Canada and the Federal Aviation Administration examined external lighting and night vision goggle interaction by quantifying the effects of incompatible lighting on visual acuity and recording pilot comments. Four observers and three sets of lights were tested using Landolt ring visual acuity charts created for distances of 15.2, 30.5 and 45.7 m. NVG compatible external lights provided consistent acuity scores in a symmetrically lit visual field. Acuity scores varied greatly with incompatible lights that caused an asymmetric viewing field. Implications for civil NVG operations are discussed.