Experimental Study On Polarimetry Imaging Using Streak Tube Imaging Lidar

Polarization imaging technique is widely researched currently. It can provide new information for detected targets with the unique ability of detection and identification. This technique has good application prospect in remote sensing, geological exploration, material analysis, marine monitoring and medical diagnosis. We applied the polarization imaging technique to the streak tube imaging lidar system and designed the polarization imaging system. The configuration of this system is simple and easily operated. Also it improved the detection probability of the streak tube imaging lidar for the targets in complicated background.Firstly, we designed and set up the experimental system of streak tube polarization imaging lidar. According to the measurement principle of degree of polarization (Dop), the special orientations of polarization optics were derived on the situation of elliptically, circularly and linearly polarized light. Based on the theoretical calculation, the experimental system of polarization imaging using streak tube lidar was set up. The streak tube detector can get the two polarized light splitted by wollaston prism on the single pulse measurement and output two streak images. Through the two streak images, the intensity and Dop images of targets can be obtained simultaneously without any optics moved.Secondly, experimentally, the Dop of targets was studied, and the excellent detectability was verified. The Dop of different kinds of indoor targets was measured using three kinds of polarized laser. The result shows that the obvious difference exists among different targets, which suggests that we can detect and distinguish targets using the polarization information obtained by this polarization imaging system. And the linearly polarized light has the best performance. We also found that intensity and Dop of a target itself have an inverse proportion relation, so Dop is well complemental to intensity, which was verified by the experiment for multiple targets. For further verifying the special detectability of this system, we did the polarization scanning imaging experiments for the hidden target and outdoor buildings. The result shows that the Dop image has the higher contrast and can detect the targets which the intensity image can't detect. It obviously improved the detection probability for hidden and low-reflectivity targets.Finally, the possible errors existing in the polarization imaging system were analyzed, including the influence of polarization optics and image processing. The result shows that they produced the maximum error less than±0.03 on Dop calculation, which assured the veracity of the experimental data and the reliability of the imaging system.The streak tube polarization imaging lidar system set up in this paper improved the detection probability for targets. So the better detectability and discrimination can be realized, which makes the imaging system a better practical application value in targets detection and radar remote sensing.