Huilin Jiang

Laser spot detection and characteristic analysis in space optical communication

In the space laser communication, the link of communication is builded in atmospheric random channel. the laser transmission is affected by the atmospheric turbulence seriously. The communication laser is modulated to circular polarized light in order to reduce the influence of the atmospheric turbulence. A several experiments are designed to validate that the circular polarized laser is available to reduce the communication noise in the space optical communication. The methods of the laser spot detection and spot parameter analysis is put forward in this paper: Firstly the subtraction of the background is used in image preprocessing in order to eliminate the influence of static background, then a series of methods such as the local dynamic threshold segmentation, edge extraction are used to detect and recognize the spot. Finally the parameters of the spot are calculated such as spots average brightness, backgrounds average brightness and the contrast gradient, and the characteristic of the laser communication is analyzed. The experiment results show that the circular polarized laser can enhance the contrast and improve the communication quality in the spatial optical communication. This method satisfies the request of real-time processing in communication, and is also effective and practical. practical.

Research on the system scheme and experiment for the active laser polarization imaging

The polarization imaging detection technology increased the polarization information on the basis of the intensity imaging, which is extensive application in the military and civil and other fields. The research present and development trend of polarization imaging detection technology was introduce, the system scheme of the active polarization imaging detection was put forward, and the key technologies such as the polarization information detection, optical system design, polarization radiation calibration and image fusion approach was analyzed. On this basis, detection system by existing equipment of laboratory was set up, and on the different materials such as wood, metal, plastic and goal was detected by polarization imaging to realize the active polarization imaging detection. The results show that image contrast of the metal and man-made objects is higher, the polarization effect is better, which provided the basis on the better performance of the polarization imaging instruments.

Study on the measurement system of the target polarization characteristics and test

The polarization imaging detection technology increased the polarization information on the basis of the intensity imaging, which is extensive application in the military and civil and other fields, the research on the polarization characteristics of target is particularly important. The research of the polarization reflection model was introduced in this paper, which describes the scattering vector light energy distribution in reflecting hemisphere polarization characteristics, the target polarization characteristics test system solutions was put forward, by the irradiation light source, measuring turntable and camera, etc, which illuminate light source shall direct light source, with laser light sources and xenon lamp light source, light source can be replaced according to the test need; Hemispherical structure is used in measuring circumarotate placed near its base material sample, equipped with azimuth and pitching rotation mechanism, the manual in order to adjust the azimuth Angle and high Angle observation; Measuring camera pump works, through the different in the way of motor control polaroid polarization test, to ensure the accuracy of measurement and imaging resolution. The test platform has set up by existing laboratory equipment, the laser is 532 nm, line polaroid camera, at the same time also set the sending and receiving optical system. According to the different materials such as wood, metal, plastic, azimuth Angle and zenith Angle in different observation conditions, measurement of target in the polarization scattering properties of different exposure conditions, implementation of hemisphere space pBRDF measurement.

Research on the laser transmission characteristics simulation and comprehensive test in complex channel environment

The laser transmission characteristics affected in the complex channel environment, which limits the performance of laser equipment and engineering application severely. The article aim at the influence of laser transmission in atmospheric and seawater channels, summarizes the foreign researching work of the simulation and comprehensive test regarding to the laser transmission characteristics in complex environment. And researched the theory of atmospheric turbulence effect, water attenuation features, and put forward the corresponding theoretical model. And researched the simulate technology of atmospheric channel and sea water channel, put forward the analog device plan, adopt the similar theory of flowing to simulate the atmosphere turbulence .When the flowing has the same condition of geometric limits including the same Reynolds, they must be similar to each other in the motivation despite of the difference in the size, speed, and intrinsic quality. On this basis, set up a device for complex channel simulation and comprehensive testing, the overall design of the structure of the device, Hot and Cold Air Convection Simulation of Atmospheric Turbulence, mainly consists of cell body, heating systems, cooling systems, automatic control system. he simulator provides platform and method for the basic research of laser transmission characteristics in the domestic.

Flexible Laser Polarization Coding Modulation Technology of Space Optical Communication

In order to adapt to non-mechanical adjustment environment of space optical communication, a flexible technology of laser polarization coding modulation is put forward. Liquid crystal Phase modulation mechanism and electronically controlled principle of laser polarization coding modulation are introduced, Principle block diagram is presented, and the experiment is accomplished by means of designed experiment device, also experimental data are given. It is showed from the results that the technology can carry on wide-spectral precision control and adjustment of laser polarization parameter under the non-mechanical adjustment condition.

An algorithm of far-distance pulse laser energy density base on image processing

A method of laser energy density distribution measurement is presented in this paper. Dot-matrix method and CCD imaging method are combined in pulse laser far-distance energy density measurement system. The laser energy data is received by detectors on the reflective board, and the laser spot reflected by the reflective board is acquired by the CCD camera. The relation of laser spot image gray and energy data is gotten by image processing algorithms, and energy density distribution is analyzed according to the model of laser energy. Algorithms principle and process are presented detailedly in this paper.

Study of a mixture programming software on atmosphere transmission

The effectiveness of dynamic and static physical properties on weapons system performance and efficiency of operations, has been designed and use of weapons systems necessary to consider the important issues. Using the software of MODTRAN atmospheric model to complete atmospheric simulation and modeling. Whilemean designed the MODTRAN software with mixed programmes in VC++ and FORTRAN languages to achieve the reutilization. The result is similar to the calculational result of the original Modtran atmospheric models software. This method is feasible and credible.