Special issue-Polarization detection and imaging

Study on UV polarization reflection characteristics of sweat latent fingerprints(Invited)
Wang Feng, Jia Rong, Liu Xiao, Zhai Hao, Wang Sunchen, Wu Yunzhi
2020, 49(6): 2020101. doi: 10.3788/IRLA20201011
[Abstract](337) [FullText HTML] (143) [PDF 2758KB](69)

Sweat latent fingerprint was the most common type of fingerprint on crime scenes, featuring features that disappeared quickly and were not easily detected. According to its characteristics, the UV polarization imaging detection technology was used for target detection. Compared with the traditional intensity image, the polarization parameter image could improve the target contrast and help to distinguish the targets in different backgrounds. However, the UV polarization imaging detection technology was sensitive to angles, bands and guest materials. Therefore, through the design of reasonable experiments, the characteristics of the UV polarization reflection characteristics of the sweat latent fingerprints with angle, band and guest materials were analyzed. The results show that the sweat latent fingerprints exhibited regular polarization characteristics at different angles; among the four spectral polarization channels provided by the system, the near-ultraviolet bands are well reproducible and distinguishable; the polarization characteristics of different guest materials varied greatly. The UV-polarized reflection characteristics of the comparative analysis samples effectively improved the detection and recognition performance of latent fingerprints, and provided a basis for the UV-polarized imaging detection technology of sweat latent fingerprints.

Rapid identification of metal debris in complicated scenes by using polarization imaging(Invited)
Xiong Zhihang, Liao Ran, Zeng Yaguang, Liu Jin, Ma Hui
2020, 49(6): 20201012. doi: 10.3788/IRLA20201012
[Abstract](569) [FullText HTML] (164) [PDF 885KB](97)

Crimes associated to explosives always kill the lives of people, destroy the facilities, and threaten the public security. Rapid identifying the medal debris from the residuals of the explosives in criminal scenes is the key to speed up the detection of these criminal cases. Responding to these applications, in the paper,  a method was proposed based on polarization imaging to rapidly identify the medal debris from the complicated scenes. Two setups were built, which can respectively capture polarization images with multiple colors and in a simultaneous imaging manner. Experiments of the medal and non-medal debris and their mixtures show that polarization imaging can effectively identify the medal debris if the incident angle polarization, and wavelength of the illuminating light are appropriately set. Simulations based on Fresnel formula show how the polarization degrees and angles change with the incident angle, polarization, and wavelength of the illumination light. And the results suggest that polarization imaging can identify the types of the medal debris, which is proved by the additional experiments. In summary, it is indicated that polarization imaging has the potential to rapidly identify the medal debris from the complicated scenes which would help for the physical evidence in criminal detections.

Advances on theory and application  of polarization information propagation(Invited)
Guo Zhongyi, Wang Xinyang, Li Dekui, Wang Pengfei, Zhang Ning, Hu Tianwei, Zhang Man, Gao Jun
2020, 49(6): 20201013. doi: 10.3788/IRLA20201013
[Abstract](2999) [FullText HTML] (1093) [PDF 2436KB](346)

The polarization state of light is the basic attribute of electromagnetic wave. Polarization information is an engineering science and applying technology, which uses the polarization states of light as the information representation, requiring proper characterizing methods to be described. Due to the scattering characteristics of atmosphere, light has a special polarization distribution pattern on the earth surface, which can be used for autonomous navigation in near-earth space. At the same time, the transmissions of different polarization states in various scattering media also have some specific transmission characteristics. Therefore, the investigations on the transmission characteristics of polarization information in different dispersive media have important values for its wide applications in modern military, aviation, marine and other fields. Meanwhile, in recent years, the optical polarization imaging has been widely applied for achieving clear imaging in haze, underwater and other scattering media systems, in which many excellent research results have been obtained. In this paper, various presentation forms of the polarization states of light, transmission characteristics of polarization information in different dispersion media systems, polarization information recovery algorithm, and application of polarization dehazing technology were mainly introduced. Lastly, the future-development trends for the applications of polarization information was prospected.

Review of underwater polarization clear imaging methods
Zhao Yongqiang, Dai Huimin, Shen Linghao, Zhang Jingcheng
2020, 49(6): 20190574. doi: 10.3788/IRLA20190574
[Abstract](1241) [FullText HTML] (323) [PDF 10031KB](300)

Underwater images often suffer from many typical problems: in a complex optical environment, the quality of underwater images drops sharply, and features such as color and brightness are often attenuated seriously, which makes it difficult to improve the quality of underwater images. Polarization imaging can effectively suppress underwater scattering. In the underwater imaging environment, according to the polarization characteristics of the signal, backscatter and forwardscatter light, the impact of different components on the image is solved. Based on the underwater physical imaging model and the principle of polarization imaging, the principle of underwater polarization imaging is described in detail, and several classic underwater polarization imaging methods are emphasized. The current underwater imaging technology based on polarization characteristics is summarized, and according to their actual effect, these methods are evaluated and analyzed. What's more, based on the advantages and disadvantages of the existing underwater polarization imaging technology and their actual results, the future development of the underwater polarization imaging technology is summarized.

Multiband submarine photoelectric polarization imaging detection simulation study based on water surface characteristics ripple
Wu Hengze, Wang Dacheng, Jin Weiqi, Qiu Su, Xue Fuduo, Yang Jie
2020, 49(6): 20190547. doi: 10.3788/IRLA20190547
[Abstract](4826) [FullText HTML] (1262) [PDF 1302KB](129)

Submarine detection is a key technology of coastline defense, the direct and indirect imaging to detect submarines both involves solving the problem of detecting the water surface ripple. 3D surface measurement method based on polarization detection can effectively detect the water corrugated surface, in which the detection and calculation of surface polarization characteristics is an important part of surface reconstruction. The model of water surface polarization was established. Visible and infrared waveband of the water polarization characteristic under different water temperature, different meteorological conditions were simulated and analyzed. The results show that the surface polarization is s polarization in the visible waveband and p polarization in the middle and long infrared waveband, degree of polarization first increases with the increase of incident angle and then decreases, moreover the degree of water surface polarization increases with the rising of temperature. The degree of water surface polarization in visible, middle infrared and long infrared waveband was measured by polarization measurement system based on Stokes vector. The results of the simulation were consistent with the measured results, which proved the accuracy of the polarization model used. The characteristics of polarization imaging detection in common wavebands were analyzed, which can provide theoretical simulation and experimental methods for the analysis and calculation of polarization characteristics of water surface.

Research on coating materials detection and recognition based on infrared spectral polarization degree contrast
Chen Weili, Xu Wenbin, Wang Shuhua, Chen Yan, Zhang Yazhou, Li Junwei, Deng Rong
2020, 49(6): 20190445. doi: 10.3788/IRLA20190445
[Abstract](1418) [FullText HTML] (843) [PDF 1035KB](82)

In order to reduce the accuracy of material infrared recognition, a common method was presented to change the emissivity of material surface by coating the material surface. Firstly, the influence of the surface emissivity of the target material on the infrared characteristics of the target material was deduced and analyzed through the Stokes expression of the infrared radiation polarization transmission model of the target material based on the micro-plane element theory. The theoretical analysis results show that the change of the surface emissivity of the target material does not affect the infrared polarization of the surface. Secondly, in view of the irrelevance between the material surface emissivity and infrared polarization characteristics, this method of coating material was proposed based on the spectral degree of polarization contrast. And the infrared hyperspectral polarization imaging characteristics of coating materials with different surface emissivities on the same substrate and coating materials with the same emissivity on different substrates were verified and analyzed. The results show that the change of the surface emissivity of the coated material does not affect the polarization degree of the infrared spectrum. And even if the target material is coated with the same emissivity coating, the characteristic of spectral polarization degree is more obviously different than that of spectral radiation brightness. The research results can provide a new method for infrared camouflage material detection and recognition.