Jin Duan

Review of polarization imaging for international military application

Polarization is a primary characteristic of electromagnetic wave. Polarization is another field of the light except the intensity, wavelength, and coherence. Polarization can indicate the different attributions that decided by objects, such as surface features, roughness, shading, shape and so on. Polarization Imaging is a useful complement to traditional intensity and spectral imaging methods with great potential in many application fields. In the future war, the advantages of polarization are significant for target detection and recognition in the increasingly complicated battlefield environment. In this paper, the research progress is generally introduced in military application in four fields: 1) target polarization characteristics and simulationenhance contrast, distinguish the target and background; 2) polarization transmission characteristics- observe target through the smoke and fog of War; 3) polarization imaging detection methods- improve the imaging quality, enhance the information available; 4) polarization image processing- improve detection and tracking performance.

The research of laser polarization scattering characters in atmosphere medium

When the laser through the atmosphere ,air molecules and aerosol particles can cause scattering of laser transmission process,attenuation of laser energy ,and also change the polarization characteristics of laser,in the end the change will affect the result of the last detected image. On the problem of polarization atmospheric transmission theory imperfection,solve the scattering amplitude functions about the scattering of homogeneous spherical particle and the scattering cross section function from Maxwells electromagnetic field equation, at the same time, carry out the theoretical research of polarized light scattering characteristics in different medium based on Stokes-Mueller matrix,focus on the character of polarization scattering, conclusion the change rules of polarization state ,degree of polarization,and other polarization parameters,and analysis the relationship of the concentration of transmission medium, transmission distance and the particle diameter by computer numerical simulation. The result indicates that depolarization factor of polarized light is closely related to the concentration of transmission media, the distance of transmission, the particle diameter, revealing that the higher concentration of transmission media, the more obvious depolarization phenomenon which establishes the fundamental of the target being recognized better for the presenting image of depolarization

An adaptive fusion strategy of polarization image based on NSCT

An improved image fusion algorithm based on the NSCT is proposed in this paper. After decomposition NSCT method of multi-scale and multiple directions, polarization image was decomposed into two parts: low frequency sub-band and high frequency band-pass images. The fusion strategy of combining local regional energy and gradient structure similarity were used in low-frequency coefficients. While in the high-frequency band-pass coefficients part, the fusion strategy of the location spatial frequency as the correlation coefficient was used. The intensity image and polarization degree image are fused for improving the sharpness and contrast of the image. The experiments show that the algorithm is effective to improve the imaging quality in the turbid medium.

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.

Experiment of polarization transmission characteristics and polarization imaging in simulation smoke/fog environment

In light transmission processing, light is effected by the fog/haze/smoke/dust environment usually. Thus reduce the capability of traditional photo-electric instrument in detection, transmission, imaging, because of the attenuation, scattering, absorbing of the atmosphere. Polarization transmission characteristics exist the potential possibility in observing object through fog and smoke, increasing observation distance, improve the environment adaptability of the photo-electric instrument. The influence of polarization transmission characteristics are analyzed by environment testing experiment in this paper, including light intensity, degree of polarization, angle of polarization etc. We research smoke and fog environment simulation technology, builds the process-controlled and parameter-measured indoor equipment to simulate smoke/fog environment. The experiments of the polarization characteristic are tested in two kinds of transmission mediums separately, which are water fog and oil smoke. The attenuation ratio is measured in different kinds of smoke concentrations. Polarization imaging experiment are tested separately in different kinds of illuminance lights, which are daylight lamp, LED lights and projector lights. The images are captured by imaging CCD with linearly polarized filters on degree 0, 60, 120. The polarization images on three directions are processed by image infuse algorithm. The experiment results are provided as the theory foundation and data reference in field of polarization transmission.

Polarized light in turbid medium transmission characteristics

the polarized light in the atmosphere, water and human tissue is more application. For polarized light in turbid medium of different integrated transmission characteristics, this paper adopts the mie scattering theory polarized light scattering method research in turbid medium, the transmission characteristics of polarized light in turbid medium is given in the model, the change law of polarization light intensity change. Finally based on the coherent polarization theory, USES the cross spectral density partially coherent light polarization characteristics of transmission in the transmission process changes to make predictions.

Study on polarization image methods in turbid medium

Polarization imaging detection technology in addition to the traditional imaging information, also can get polarization multi-dimensional information, thus improve the probability of target detection and recognition.Image fusion in turbid medium target polarization image research, is helpful to obtain high quality images. Based on visible light wavelength of light wavelength of laser polarization imaging, through the rotation Angle of polaroid get corresponding linear polarized light intensity, respectively to obtain the concentration range from 5% to 10% of turbid medium target stocks of polarization parameters, introduces the processing of image fusion technology, main research on access to the polarization of the image by using different polarization image fusion methods for image processing, discusses several kinds of turbid medium has superior performance of polarization image fusion method, and gives the treatment effect and analysis of data tables. Then use pixel level, feature level and decision level fusion algorithm on three levels of information fusion, DOLP polarization image fusion, the results show that: with the increase of the polarization Angle, polarization image will be more and more fuzzy, quality worse and worse. Than a single fused image contrast of the image be improved obviously, the finally analysis on reasons of the increase the image contrast and polarized light.

Target detection technology based on polarization imaging in the complex environment

The polarization imaging detection technology has some advantages in revealling targets in complex background, identify stealthy, camouflage, dim, false target, and penetrating smoke. This article summarizes foreign polarization imaging detection technology development process, the status and development trends, and discusses the foreign technical level, further research on key technology of polarization imaging detection, put forward a scheme of the detection system based on polarization imaging in complex environment, through increasing the polarization dimension information based on intensity imaging , on which intensity and spectrum cannot reflect, and can significantly enhance the difference between target and background, increase influencing distance in the haze, smoke and dust environment , through the analysis, we elucidated the feasibility and availability of the system, in order to enhance the future of the target detection and recognition ability of photoelectric equipment.

Simulation of electro-optical imaging system based on OpenGL

With the development of electro-optical imaging system technology and simulation technology, and the demand of optimizing the new type electro-optical imaging system theoretical model, more and more scientific research institutes, colleges and universities research on the simulation of electro-optical imaging system, and the better results were obtained. Simulation technology saved the cost of system design development, meanwhile, some complex and hard to re-implement experiments can be carried repeatedly. According to the demand of complex environment construction technology and the requirement of imaging simulation system fidelity, considering the performance of electro-optical imaging system, an electro-optical imaging system is modeled. The modeling has two aspects which is scene characteristic modeling and electro-optical system modeling. Scene characteristic modeling can construct dynamic scenes in different kinds of complex environments by using powerful OpenGL three-dimension model visualization technology. Electro-optical system modeling is consist of optical system and imaging detector. Electro-optical imaging system simulation model is established with the analysis of electro-optical imaging system theory. The use of modular design concept and general interface technology is combined. Different imaging effect is received under different parameters by modifying the model’s related parameters. The experimental results show that, the image produced from simulation basically reflects the performance of imaging system, so this kind of image can be used as a information source for imaging system performance analysis. It provides a simple and feasible method for the analysis of imaging system performance, which has a very important practical significance.