Abstract:The surface temperature of a ballistic missile in flight is a key point concerned by both the missile attacking side and the missile defense side. The surface temperature and infrared radiation source of ballistic missiles in their boost phases, middle phases and re-entry phases are reviewed. The equilibrium temperature of the warhead and decoy of the ballistic missiles in middle phases are given mainly. The warhead nearly keeps its initial temperature because of higher thermal inertia, whereas the balloon decoy reaches its equilibrium temperature quickly because of lower thermal inertia. Finally, that the dynamic thermal radiation measurement in actual flight tests is the important direction of surface temperature theory study is pointed out.

Abstract:The important role and function of long path absorption cells in gas concentration detection are studied. Six kinds of long path gas absorption cells with different structural principles are analyzed in detail. Their advantages and disadvantages are compared with each other. According to the development demands for gas concentration spectrum detection, the development trend of long path absorption cells which have the advantages of compact configuration, low cost, low light energy loss, easy regulation, easily calculated optical path and high resistance to interference is clarified.

Abstract:The photosensitive properties of PbS films can determine the performance of PbS detectors. The PbS films are the core and foundation of PbS infrared detectors and are also the research direction for the modification and improvement of PbS infrared detectors all the time. The reaction mechanisms of three processes including high temperature method, Kodak method and hydrazine method in the formation of PbS films are analyzed. The results show that the photosensitive films are all related to the formation of PbSO4. The X-ray diffraction test result shows that there are PbSO4 in PbS poly-films. So, it suggests that the formation of the PbS solid solution containing low concentration PbSO4 is one of the reasons for PbS films to have photosensitive properties.

Abstract:Infrared polarization imaging can improve the ability to detect camouflage or stealth targets. As a reconnaissance means against infrared stealth, the infrared polarization imaging technology has become an important research content at home and abroad. By analyzing the progress of infrared polarization imaging, the infrared polarization imaging technology is suggested to be used in target detection. To study the polarization scattering characteristics of camouflage targets, an infrared polarization imaging system is used to detect the target scenes with and without three-color camouflage nets. It is found that the infrared polarization imaging can be used as a new approach to the detection of camouflage or stealth targets and it has a good imaging result. In addition, the research shows that the unique advantage of polarization detection in recognition of camouflage targets with low reflectivity against complex background is also valid in the mid-infrared wavelength band. Moreover, the polarization angle imaging is very sensitive to the external physical characteristics of camouflage nets.

Abstract:As the main remote sensing means for cloud detection, millimeter wave cloud measurement radars can provide timely, accurate and reliable information for the inversion of macroscopic and microscopic parameters of cloud. The study of the calibration technology for millimeter wave cloud radars is not only helpful to the full use of their observation data, but also is helpful to the improvement of observation quality. Although the internal calibration systems for millimeter wave cloud radars can automatically detect the main operation parameters and revise the detected results so as to keep the stability and authenticity of the detected results, they do not take the antenna characteristics and the interaction among different components into consideration. Therefore, it is particularly urgent to study the external calibration technology for millimeter wave cloud radars. On the basis of the external calibration experiments of airborne millimeter wave cloud radars at home and abroad, the external calibration technologies are presented and analyzed and the process of external calibration is determined. This provides the reference for the initial airborne external calibration experiment in our country in the future.

Abstract:The in-orbit synchronous calibration of a spaceborne optical sensor needs to use the ground synchronous spectral measurement as the data support. The accurate surface reflectance is one of the important prerequisites for obtaining high-precision calibration results. The traditional field ground reflectance measurement methods use a single spectrometer to measure a target and a reference panel in turn. In the case of dramatic irradiation change, the traditional measurement methods can not keep the radiation condition of the target and reference panel to be consistent. By using a dual-spectrometer method to measure the reflectance-time series of the ground objects in the field, the problem of inconsistent radiation condition occurred possibly in the traditional methods is avoided. By comparing the measurement result of the dual-spectrometer method with that of the single-spectrometer method, the correlation coefficient is up to 0.998. Moreover, the reflectance curve obtained by the dual-spectrometer method is closer to the actual spectrum. Thus, the feasibility of the dual-spectrometer method is verified.

Abstract:By using terahertz (THz) time-domain spectroscopy to analyze part production processes of traditional Chinese murals, the THz time-domain reflection spectra of each mural production process are obtained. The THz spectral characteristics of traditional Chinese murals in the frequency range from 0.2 THz to 1.0 THz are studied. The THz absorption spectra and refractive index of traditional Chinese murals at room temperature are obtained. The result shows that there is a remarkable difference in the mean refractive index and peak absorption coefficient frequency for each sample. It can provide the reference for the application of THz time-domain spectroscopy in mural information extraction.

Abstract:There exist a large number of irrelevant and redundant features in large-scale infrared spectrum datasets. To solve this problem, a dynamic weighted infrared spectrum feature selection algorithm (MBDWFS) is proposed. The algorithm deletes the irrelevant and redundant features in an original spectrum dataset by combining the symmetric uncertainty metrics with Markov Blanket. Then, a smaller scale optimal feature subset is obtained. By comparison with three classical feature selection algorithms FCBF, ID$_3$ and ReliefF, it shows that the proposed MBDWFS algorithm is better than the above three algorithms in overall classification performance and is more suitable to be used in the field of material infrared spectrum analysis.