Time Domain Filtering Method Based on Photon Time-of-Flight Correlation

Abstract

The invention discloses a time-domain filtering method based on photon flight time correlation. First of all, photon flight time is obtained by performing scanning by use of a laser radar under the condition of a quite low signal-to-noise ratio, then by use of the flight time correlation between photons, filtering conditions are set for determining the flight time of the photons, signal photons and noise photons are distinguished from each other, next, detection photons which are determined as the noise photons are removed, and only the detection photons which are determined as the signal photons are reserved, finally, a center of area method is applied to the signal photons, the accurate flight time of the photons is extracted, and thus distance information is obtained. Experiments show that under the condition of the quite low signal-to-noise ratio, the method provided by the invention can effectively filter the noise photons in signals obtained by scanning through the three-dimensional imaging laser radar so as to realize the purpose of denoising.

Description

technical field [0001] The invention belongs to the field of laser radar three-dimensional imaging, and in particular relates to a time domain filtering method based on photon time-of-flight correlation applicable to a photon counting laser radar system. technical background [0002] Accurately obtaining the 3D structure of the target scene has a wide range of applications. The 3D imaging lidar system uses the avalanche diode in Geiger mode as a detector, which can acquire the depth image of the target scene with high sensitivity and high precision. The lidar system obtains the three-dimensional information of the target scene by integrally sampling the target scene and then accumulating to generate a statistical histogram. [0003] In order to extract accurate time-of-flight from statistical histograms and obtain high-precision target depth estimates, it is necessary to use echo signal time-of-flight extraction algorithms such as: peak method, centroid method, fitting meth...

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Problems solved by technology

[0005] When using a dual-detection structure, the echo signal needs to enter the two APDs respectively through the beam splitter. When the strength of the echo signal is weak, this may reduce the detection probability of the target; or logic can increase the detection probability of the target. , but it also increases the false alarm rate; when combined with logic and or logic, it will be necessary to use 4 detectors, which will undoubtedly complicate the structure of the system, and will also introduce more detectors caused by time jitter error

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