Research On Key Technologies Of Fast Scanning Photon Counting Lidar Imaging

The traditional imaging methods of photon counting laser radar use a fixed long dwell time to sample the target scene.By acquiring the TOFs of 105?106 photons,the traditional imaging methods generate the photon counting histrogam to obtain the depth and intensity image.Since the traditional imaging methods need a long dwell time,it is not suitable for the real-time application.On the other hand,photon counting laser radar uses the APD that works in Geiger mode(Gm-APD)as the single-photon detector.The Gm-APD has high sensitivity and indistinguishably responsing the laser echo signal and background noise.In addition,the traditional imaging methods apply the same processing strategy for signal and noise.Under the environment of strong background light,the photon counting laser radar has a problem of high false-alarm rate.In order to obtain the accurate 3D image in a short time,we have studied the basic principle of time-correlation photon counting laser ranging and three-dimensional imaging lidar and analyzed the working principle of single photon detector.Based on these theories,for solving the problem of the traditional imaging methods need a long fixed dwell time,we have proposed an adaptive imaging method based on the single-photon detector,which can change the dwell time according to the laser echo signal reflected from the different parts of target scene.At the same time,in order to solve the problem that the traditional imaging of photon counting lidar is seriously affect by background noise,we have proposed the fast depth imaging denoise method based on the time domain correlation between the laser echo signals.By distinguishing the signal between the noise,this method can obtain the 3D image of the target scene quickly and accurately.Based on the principle of time-correlated photon counting laser ranging,we propose a realization of photon counting laser ranging system.We have built the prototype of this photon counting laser ranging system and implemented the 8.4 km distance detection in the sunlight environment.