Research On The Near Infrared Single-photon Imaging Technology

As an active imaging system,light detection and ranging(LiDAR)obtains the three-dimensional(3D)information of the targets directly.Benefitting from the advantages of high precision,high resolution,long distance,and low power consumption,the LiDAR is widely used in terrain mapping,machine vision,self-driving,forestry management,urban 3D modeling,military detection,defense,etc.In recent years,with the development of the single-photon detection technology,the single-photon LiDAR(SPL)based on single-photon detection technology has become the research with important application value.Compared with the normal LiDAR,the SPL equips with ultra-sensitive characteristics which could achieve longer distance ranging.To meet the needs of practical applications,high imaging rate,high resolution,and long-distance range have become the key research directions of the SPL.Using the near-infrared laser with a high eye-safe threshold,this thesis based on the single-photon detection technology developed the SPL systems to solve the low imaging rate and low point cloud data rate.The ultra-high detection sensitivity of a single-photon detector could expand the imaging distance and improve the imaging rate.The miniaturized single-photon laser 3D imaging systems are developed for applications such as machine vision,airborne terrain mapping,atmospheric monitoring,military strikes,defense,etc.The innovations of this thesis are introduced as follows:1)The small airborne single-photon laser scanning imaging system was developed using the 1550 nm laser pulse and the quasi-continuous GHz InGaAs/InP single-photon detector.The photon-counting denoising algorithm was proposed for the high background noise.Four airborne altitude measurement experiments were successfully carried out.The 3D point cloud detection of ground targets was realized.2)A single-photon ceilometer at 1550 nm was designed which used two repetition rates laser pulse to expand the effective ranging distance of the system by 19 times.The ceilometer successfully detected the echo signals of the cloud layer at the height of 17 km.The accuracy,dwell time and ranging distance of the ceilometer in this work exceed those of the typical ceilometer products.3)A self-gating single-photon scanning imaging method was proposed.The continuous scanning method was used to increase the imaging rate.The double repetition rate laser pulse was used to extend the imaging distance.What's more,the double repetition rate was used to denoise effectively.Using the range gate of signals to adaptive gating improved the signal-to-noise ratio from-1.72 dB to 5.91 dB.In this way,the high-speed SPL was realized with an effective data generation rate of 1.3×10~5 cps.