Guangtongxin yanjiu (Aug 2024)

All-weather Single-photon Lidar

  • LIU Yingjian,
  • LIU Hangyu,
  • JIANG Kai,
  • WEI Renjie,
  • SUN Baorui,
  • YE Nan,
  • WANG Liang

Abstract

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【Objective】Single-photon detection and single-photon ranging systems have widespread applications in three-dimensional imaging and long-distance spatial remote sensing. However, device limitations and background noise from the sun light limit the application to only nighttime conditions.【Methods】We have improved traditional laser radar systems by implementing all-fiber optics systems with ultra-narrowband fiber optic filtering, leading to significantly improved system stability. By implementing mechanical motion control, we are able to attain single-photon imaging systems with ultra-wide scanning and ultra-high resolution. The systems can operate in optical environments that are typically challenging, such as daytime or foggy weather. Moreover, the laser radar system is designed based on the 1 550 nm wavelength which has good atmospheric penetration and low transmission loss, enhancing its ability to work in foggy and rainy conditions.【Results】In a foggy condition with a visibility of about 500 m, the system achieves three-dimensional imaging of objects 1.6 km away, which is a distance 3 times longer than the visibility at the time. The distance resolution can be significantly enhanced by optimizing the intensity and distance information of the histogram using the minimized negative logarithmic likelihood function, with the assistance of a high-resolution time/digital converter and the model constructed by the system response function of the laser radar. Compared to the maximum value method with a distance resolution of 0.05 m, this system achieves a distance resolution of 0.006 m via the minimized negative logarithmic likelihood function method. Additionally, the image normalization processing is performed to suppress fluctuations in photon technology and eliminate noise in the image. The 1 550 nm all-fiber laser radar system has strong mechanical stability and can work in adverse weather conditions.【Conclusion】It has significant application value in remote sensing and mapping, ground and vehicle-mounted laser radar, and other fields.

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