Abstract:The related performance parameters of mid-wave and long-wave infrared detection systems are analyzed, calculated and compared in the respects of detector characteristics, target radiation characteristics, background radiation characteristics, atmospheric transmission and infrared system design. The data which is of value to practical uses is provided. The suggestion on band selection is made for the design of infrared detection systems.

Abstract:A long wave infrared (8-12.5 μm) focal plane array can not operate better than medium and short wave ones in many respects. Its non-uniformity and blind-pixel problems are quite serious. A MARS VLW RM4 320×256 HgCdTe long wave infrared focal plane array detector with a wavelength response range from 7.7 μm to 12 $\upmu$m is imported from Sofradir Company in France. On the basis of a high frame frequency and low-noise information acquisition system of which the dynamic range is calibrated, a thermal infrared imaging system is developed. Its dynamic range is from 250 K to 330 K and Noise Equivalent Temperature Difference (NETD) is less than 50 mK. According to the response characteristics of the pixels in the array detector, the non-uniformity and blind-pixel correction method suitable for thermal infrared imaging systems are studied. A non-uniformity and blind-pixel detection method based on radiation calibration is put forward. The experimental result shows that the method is better than the two-point method. It is easy to be implemented in engineering. The result based on radiation calibration is useful for more precise temperature inversion.

Abstract:On the basis of advantages of Long Wave Infrared (LWIR) polarization imaging in the field of target detection and recognition, a LWIR polarization imaging detection system is built. The LWIR polarization images of some typical indoor and outdoor objects are collected by the system. The image information of three kinds of targets, such as Stokes vectors ($I, Q, U$), degree of linear polarization, angle of polarization and two combined features δ and ρ, is extracted. Their characteristics are analyzed in detail. A new method for enhancing target-background contrast based on the infrared polarization information obtained is proposed. The experimental result shows that the method is feasible and effective.

Abstract:On the basis of Mie scattering theory, the effect of fog with different concentration on the polarization characteristics of a surface ship target is analyzed in a simulation experiment. By carrying out numerical simulation with a 6SV model, the data about the effect of fog on target polarization characteristics is obtained. It is found that with the increase of fog concentration, the depolarization phenomenon is getting more obvious. The reason of this depolarization phenomenon is analyzed. The result is of reference value to the application of polarization detection technologies in fog environment.

Abstract:When the heat insulation layer of ship thermodynamic pipeline is damped, its heat insulation effectiveness can be reduced and the pipeline can be corroded. A model of damped heat insulation layer is established. The finite volume method is used to calculate the variation of temperature field, outer surface temperature and heat transfer loss of the heat insulation layer of a vapor pipeline with the damp thickness of the layer. The result shows that when the damp thickness is up to 20 mm, the temperature of the heat insulation layer will exceed its standard. For a damp area with same thickness, the nearer the outer surface is, the higher its temperature is. This reveals the importance of protecting the outer surface of a heat insulation layer and provides the basis for infrared thermal imaging diagnosis of heat insulation layers.

Abstract:A near infrared and visible light Fourier transform spectrometer needs to use a multiplied reference laser interfere signal as its sampling signal. Since a phase-locked loop frequency multiplier is not suitable for low frequency non-periodic signals and the traditional digital multiplier method may generate a large error, an improved algorithm based on the traditional digital multiplier method is put forward. The algorithm is simulated and verified. The result shows that when the improved algorithm is used, the non-uniformity error of output waveform is improved from the range of -2% to 1.6% to the range of -0.82% to 0.4%. The non-uniformity error is improved greatly.

Abstract:The polarization characteristics of both a camouflage target in grass background and the background are studied experimentally in different wavebands at different observation angles on an indoor simulation platform. The optimal angle and waveband for detecting the camouflage target by using polarization imaging are obtained and verified under the outdoor condition. The experimental result shows that the polarization imaging can be used to detect the camouflage target hidden in the grass background under certain conditions.

Abstract:Currently, most of induction bath showers on sale use reflective infrared sensors to control their water control systems. Since the reflective infrared sensors may give wrong information, waste of water may occur. To avoid this phenomenon, a new low energy consumption infrared water control system for showers is designed. The system is based on a pyroelectric infrared sensor module. When the continuous infrared signals emitted from a moving human body are received, the module may output electric signals to an electromagnetic relay. Then, the electric relay lets a solenoid valve be turned on. Thus, the misinformation problem is solved effectively. In addition, because a tubular flow generator is used, the module can save electric energy. The experimental result shows that the shower can run reliably and can be put into practical use.

Abstract:Vegetation plays an irreplaceable important role in soil improvement, sand fixing, environment purifying, climate adjusting and human survival etc. Therefore, the study of vegetation is indispensable for the research on the ecological environment of the earth. The more and more mature thermal infrared detection technology can provide a more rapid and effective means for the vegetation research. By measuring the brightness temperature of the typical ground vegetation in Cangchun city, Jilin Province, the thermal radiation properties of different kinds of vegetation are obtained. The thermal radiation properties of different kinds of vegetation are studied in different wavebands and time phases at different angles. The result shows that the brightness temperature of vegetation is affected by the kind of vegetation largely, by the waveband less, by the measurement time obviously and by the detection angle greatly. It provides an important basis for more accurate recognition and classification of vegetation.