Optical Antenna System Design for 3D Imaging Lidar

A new aspheric surface pre-collimation lenses system for the optical antenna of three-dimensional （3D） imaging of lidar has been optimally designed and simulated by optical design software CODE-V.Four kinds of aspheric surfaces spherical lenses including the sections of spherical,elliptical,hyperbola,and parabola have been researched.The optical system,including the elliptical cylinder lenses collimation and the optical antenna,can be realized less than 5 rad collimation angle for dot source semiconductor laser beam.

Performance analysis of ghost imaging lidar in background light environment

The effect of background light on the imaging quality of three typical ghost imaging(GI) lidar systems(namely narrow pulsed GI lidar, heterodyne GI lidar, and pulse-compression GI lidar via coherent detection) is investigated. By computing the signal-to-noise ratio(SNR) of fluctuation-correlation GI, our analytical results, which are backed up by numerical simulations, demonstrate that pulse-compression GI lidar via coherent detection has the strongest capacity against background light, whereas the reconstruction quality of narrow pulsed GI lidar is the most vulnerable to background light. The relationship between the peak SNR of the reconstruction image andσ(namely, the signal power to background power ratio) for the three GI lidar systems is also presented, and theresults accord with the curve of SNR-σ.

Effect of time bin size on accuracy of streak tube imaging lidar

Streak tube imaging lidar （STIL） is an active imaging system that has a high range accuracy with tile use of a pulsed lapser transmitter and streak tube receiver to produce 3D range inlages. This work investigates the effect of tile time bin size oil the range accuracy of STIL systems based on the peak detection algorithm. The nunlerical simulation indicates that the time bin size has a significant effect on the range aceuracy, resulting in a modified analytical estimate of the range error. An indoor experilnent with a planar target is carried out to validate the theory that shows the linear relationship between tile range error and the time bin size. Finer 3D depth iinages of a fist model are acquired by using a smaller time bin size and the best range error of 0.003 In is achieved with the optimal time bin size of 0.07 ns.

Depth resolution improvement of streak tube imaging lidar system using three laser beams

The work proposes a three-laser-beam streak tube imaging lidar system. Besides the main measuring laser beam,the second beam is used to decrease the error of time synchronization. The third beam has n＋0.5 pixels＇ difference compared to the main measuring beam on a CCD, and it is used to correct the error caused by CCD discrete sampling. A three-dimensional（3D） imaging experiment using this scheme is carried out with time bin size of 0.066 ns（i.e., corresponding to a distance of 9.9 mm）. An image of a 3D model is obtained with the depth resolution of 〈2 mm, which corresponds to ~0.2 pixel.

Delayed range-gating super-resolution imaging lidar with high accuracy

We present a range-gating delayed detection super-resolution imaging Iidar with high accuracy based on the signal intensities of three consecutive delay samples. The system combines the range and signal intensity information from multi-pulse detections to calculate the pulse peak position under the assumption of a Gaussian pulse shape. Experimental results indicate that the proposed algorithm effectively calculates pulse peak position and exhibits excellent accuracy with super-resolution. Accuracy analysis shows that accuracy is best improved by enhancing signal-to-noise ratio, strategically selecting samples, reducing pulse width, and appropriately choosing the delayed periods between samples.