{'fraction_non_alphanumeric': 0.018775510204081632, 'fraction_numerical': 0.005714285714285714, 'mean_word_length': 5.255102040816326, '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}}
Adaptive Target Profile Acquiring Method for Photon Counting 3-D Imaging Lidar

A direct-detection 3-D imaging lidar is capable of acquiring a depth image of noncooperative targets in long distance, using Geiger mode avalanche photodiodes and the technique of time-correlated single-photon counting. However, conventional 3-D imaging lidar has a long data acquisition time. This paper introduces a spatially adaptive method to obtain target profile rapidly for 3-D imaging lidar by exploiting discontinuities between targets and background in the depth domain. The idea behind our strategy is using an adaptive scanning step to localize the regions near the depth boundaries and perform fine scans only to these regions. Fine scans only for those specific regions ensure the recovery accuracy while consuming much less data acquisition time, compared to a conventional high-resolution scanning lidar. Experimental results demonstrate that for the experimental scene, the data acquisition time decreases 85% by using the proposed method, without generating much distortion of the target profile. This method may be of considerable value to fields that need fast 3-D imaging, such as remote sensing and military reconnaissance.