Abstract:The design of mechanically athermalized longwave infrared optical systems with wide field of view and large relative aperture is studied. An optical system with the F number of 0.8 is designed for the waveband of 8 to 12 μm. It is athermalized in the temperature range -40℃ to 60℃. The analysis results show that the optical system is simple in structure and good in imaging quality. It has an optical transfer function greater than 0.5 at the spatial frequency of 20 lp/mm.

Abstract:In the growth process of heavily arsenic-doped Czochralski silicon crystal, the arsenic dopant has its strong evaporation. To suppress the influence of As evaporation on the resistivity of silicon crystal, the evaporation rate constant of As should be determined. The curve of As concentration in a crystal sample versus evaporation time is given in a measurement experiment. Then, through the linear regression analysis of the experimental curve, the As evaporation rate constant in the growth process of the heavily As-doped silicon crystal (1.43×10-4 cm/s) is obtained. The result is verified to be correct and effective in the practical applications. This is of great significance to the precise control of the resistivity of heavily As-doped silicon crystal.

Abstract:In an air-to-air missile, the amount of the data to be processed by the infrared imaging system is too large for real-time processing. To address this problem, a high-speed infrared image data acquisition system based on RapidIO and PCI-Express is presented. The design of a key modular image acquisition card which uses the XMC base plate and XMC interface board of a high-speed serial bus as its frame structure is discussed emphatically. The system not only has a dual channel data acquisition function, but also has a dual channel data broadcast function. Each channel has a data acquisition rate up to 1.2 Gbps and a code rate in the range 0 M to 400 M. The system can implement the real-time acquisition and display of high frame rate infrared images.

Abstract:To make full use of the complementary information in infrared and low-light remote sensing images and make it more convenient for visual interpretation, an image fusion method based on variation is proposed. In this variation-based mode, both the detail injection term and the structure fidelity term are defined. The spatial detail and structure characteristics of the fused images are also improved while the spectral characteristics of the infrared and low-light images are kept. A regularity energy term is incorporated into the fusion model so as to ensure the smoothness of the solution. On the basis of gradient descent flow, the fused images are obtained by numerical iteration. The experimental results show that the model can obtain the fused images containing abundant spatial and spectral information. Compared with the Laplacian pyramid decomposition-based and undecimated wavelet transform-based methods, the proposed model exhibits better fusion performance.

Abstract:To generate the simulated image of an infrared target accurately and realistically, the effects of an infrared sensor need to be simulated accurately. Sampling and blur effects are the typical main effects of infrared sensors. First, the mathematical models of sampling and blur effects are discussed. Then, both effects are taken into account at the same time. Their algorithms are combined into one algorithm by a ray tracing method and a new mathematical model is proposed. According to the established model, the simulation image under the co-action of sampling and blur effects is obtained. The experimental results show that the established model can reflect the degradation of images due to sampling and blur effects. This is helpful to the improvement of calculation accuracy and efficiency and the increase of the fidelity of infrared image simulation.

Abstract:To explore the way to use remote sensing data to monitor the thermal plume from a nuclear power plant and verify the application ability of the thermal infrared data from Landsat-8 satellite in thermal plume monitoring of a nuclear power plant, a sea area of 10×10 km$^2$ near Hongyanhe Nuclear Power Plant is selected as the research area. The cross calibration method consisting of the thermal infrared data from Landsat-8 satellite and the temperature product from the Moderate Resolution Imaging Spectroradiometer (MODIS) is used to establish a temperature information extraction model. By referring to the 'Sea Water Quality Standard', different temperature rising intensity is classified into five ranks. With the supplemented in-situ hydrological and meteorological data, the temperature field distribution and temperature rising intensity variation of the thermal plume from Hongyanhe Nuclear Power Plant are analyzed. The temperature rising curves of a step of 1℃ in different tidal states are mapped out. The areas affected by different temperature rising are obtained. The data are compared with the comprehensive result of the mathematic simulation and physical model test. The results show that with the Landsat-8 satellite data, precise monitoring of thermal plume from a nuclear power plant can be implemented.

Abstract:Electrical equipment is the device in which failures often happen. An infrared thermometer or infrared thermal imager can be used to detect the abnormal overheated part in electrical equipment and determine its surface temperature. At this time, if the infrared diagnostic criterion is incorporated, the fault severity of the abnormal equipment can be determined. Thus, the failure diagnosis of electrical equipment can be implemented. Aiming at the overheated components in electrical control boxes, both an ST80 infrared thermometer and a FLIR E320 infrared thermal imager are used to measure the temperature of an electrical control box. Through the determination of the fault severity of the component by both the surface temperature difference and the relative temperature difference, the diagnostic difference between the infrared thermometer and the infrared thermal imager is analyzed. The results show that the infrared thermal imager can monitor and diagnose the overheating defects of electrical elements while the infrared thermometer can detect the overheating defects of most electrical elements in electrical control boxes. However, the infrared thermometer is not as good as the infrared thermal imager in the diagnosis of failure severity of electrical components.