Experimental Research Of Range Accuracy On Range-gated Time Slice Laser Imaging

After years of development, laser radar combined with mechanics, optoelectronics, mathematical statistics, image processing has formed many kinds of system with their unique properties. High accuracy 3D image is widely used in industrial design, reverse engineering, exploration, target modeling and virtual reality, etc. Our direction of research is three-dimensional laser imaging on range-gated time slice. Through theoretical analysis and experimental verification, the accuracy of imaging was analyzed under different conditions.First, we have carried on a comparatively careful investigation to the related research both in domestic and foreign. The parameters of the representative radar system of different institutions and their advantages in the application were analyzed, and the necessity of our research was introduced.Secondly, the range-gated technology were comparatively detailed introduced, and the intensity distribution of the slice image was simulated by MATLAB. We compared the difference between the binary algorithm and centroid algorithm. Then we analyzed the influence factors of the accuracy of imaging.Thirdly, based on previous analysis, we designed the experimental system including the laser emission system, the synchronization control system and the signal detecting system. The test of the system was carried out. The performance of the system was as follows: the beam divergence angle is 4 degrees, frequency is 1-100 Hz adjustable, inherent delay is 13 ns, gate width was 3ns-DC adjustable, delay step was short into several picoseconds to fine sectioning. Finally, we debugged the complete system to make it work in the best condition.Then, a few groups of experiments on the range-gated imaging were carried out. For the target of 9.5m and 22 m, the accuracy can be 0.025 m when the gate width is 7ns. It is proved that a small gate width has certain advantages in the guarantee of the imaging accuracy.Finally, we discussed the applicability of centroid algorithm and proposed a new method to synthesis the range image based on curve fitting. Through the contrast experiment, we verified this method can ensure the applicability of range-gated imaging and improve the precision of imaging in the situation of the image slices were less and distributed uneven. Then we pointed out that this method has applicability in the range-gated imaging.