Optics and Precision Engineering, Volume. 33, Issue 3, 377(2025)

Technologies of real-time non-line-of-sight imaging based on time-of-flight array

Yuan HAN1, Youzhi LI1, Zhenchen JI3, Hongxu AI3, Jiaqi YAO1,2, Yanqiu WANG1, Fu ZHENG1, and Zhibin SUN1,2、*
Author Affiliations
  • 1National Space Science Center, Chinese Academy of Sciences, Beijing0090, China
  • 2University of Chinese Academy of Sciences, Beijing100049, China
  • 3North China Electric Power University, Beijing102206, China
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    To address the challenges associated with slow imaging speed, limited imaging range, and the complexity and high costs of existing non-line-of-sight (NLOS) imaging technologies, a novel real-time NLOS imaging method based on array time-of-flight (ToF) principles was proposed. A theoretical model for three-dimensional (3D) scattering NLOS imaging utilizing a planar array configuration was established, facilitating the investigation of the effects of imaging distance and light source illumination angle on system reconstruction outcomes and overall performance. An evaluation index for ToF NLOS 3D imaging was developed. This method employs an 850 nm modulated laser as the optical signal source, with a ToF camera functioning as the sensor to capture third-order forward scattering signals from concealed targets illuminated through an intermediate plane. The hidden target is reconstructed using depth information obtained from a demodulation algorithm. Experimental results demonstrate that the system can achieve real-time NLOS reconstruction of small targets, such as a plaster statue measuring 15 cm × 19 cm × 30 cm, when both the intermediate plane and NLOS objects are approximated as Lambertian surfaces within a distance of 3.5 m. The illumination angle of the light source can be adjusted between 60 and 90 degrees, resulting in a real-time imaging speed of 2.056 5 frame/s. The system features a pixel resolution of 320 × 240, with a maximum target area pixel size of 150 × 100, and a minimum horizontal distance for multiple target images without aliasing of 3.5 cm. This paper introduces key technologies for real-time NLOS imaging using array ToF, highlighting significant advancements in imaging range, speed, resolution, and interference resistance.

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    Yuan HAN, Youzhi LI, Zhenchen JI, Hongxu AI, Jiaqi YAO, Yanqiu WANG, Fu ZHENG, Zhibin SUN. Technologies of real-time non-line-of-sight imaging based on time-of-flight array[J]. Optics and Precision Engineering, 2025, 33(3): 377

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    Paper Information

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    Received: Dec. 10, 2024

    Accepted: --

    Published Online: Apr. 30, 2025

    The Author Email:

    DOI:10.37188/OPE.20253303.0377

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