{'fraction_non_alphanumeric': 0.022670025188916875, 'fraction_numerical': 0.005877413937867338, 'mean_word_length': 5.112820512820512, '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}}
Arbitrarily Tilted Receiver Camera Correction and Partially Blocked LED Image Compensation for Indoor Visible Light Positioning

Indoor visible light positioning (VLP) systems can be directly integrated with existing lighting infrastructure and achieve high-accuracy positioning when using CMOS image sensors as receivers. Due to cameras’ limited field of view (FOV), VLP systems based on multiple light emitting diodes (LEDs) require lamps to be arranged with high density, which is not practical in realistic scenarios. Additionally, smartphones held in the human hand may rotate about the x-, y- or z-axis. This article proposes a tilted receiver camera correction method for indoor VLP systems to eliminate the additional positioning errors caused by rotation. Furthermore, the proposed method can suppress the positioning errors when part of the LED light is blocked, and can therefore enhance the robustness of the VLP system. The experimental results show that the proposed VLP method can achieve average positioning error within 7 cm when more than 40% of the LED image is captured, and can achieve average positioning error of 3.9 cm when more than 90% of the LED image is captured.