Abstract:To meet the requirements of high sensitivity, real time, miniaturization and integration of an infrared camera, an image data processing system based on FPGA is designed. The system uses the four-channel output mode of a 384×288 long-wave infrared focal plane array detector, takes a chip in Altera cyclones family as the main controller and uses a 4 M bit SRAM and a 4 M bit flash as the auxiliaries. It can implement the collection and elimination of image background, oversample-superposition and digital TDI etc through instruction. The system also has the functions of push-broom scanning and staring imaging which are achieved by Verilog language. Its transplantation is strong. The experimental results show that the system can implement real-time processing of images instead of PC and obtain clear images with high sensitivity.

Abstract:A mechanical cryocooler is one of the important parts of an infrared detector. It provides a precise and stable low temperature operation environment for the infrared detector. In the engineering applications, the tuning of Proportion Integration Differentiation (PID) parameters is mostly dependent on the experience of engineers. Thus, the theoretical analysis of PID parameter design is lacked. The frequency-domain design method of PID control parameters is analyzed according to the Bode diagram, the Nyquist stable criterion and the control model of the cryocooler. The simulation results show that this method is reliable and effective and can provide guidance for the online tuning of PID temperature control parameters of mechanical cryocoolers.

Abstract:Infrared Atmospheric Sounding Interferometer (IASI) can be used to acquire stratospheric temperature profiles and analyze stratospheric gravity waves. On the basis of the neural network, a formula for IASI to retrieve the stratospheric temperature profiles in the altitude range from 25 km to 60 km is established by using the typical atmospheric profile database and the atmospheric radiation transfer mode. The retrieval results are verified according to the reanalysis results. The simulation test results show that the retrieval deviations of stratospheric temperatures are mainly close to 0 K and are not greater than 1 K. The root mean square error is between 2 K and 6 K and the root mean square error in the range from 50 hPa to 5 hPa is within 3 K. The comparison results show that the retrieval of temperature profiles from IASI_SFOV is comparable to the reanalysis data from ECMWF on the whole. The retrieval is faster and has a more complete coverage area.

Abstract:Because of the serious interference of cloud contamination with atmospheric infrared remote sensing, a large number of infrared data are abnegated. To make full use of the infrared data in assimilation to improve the initial field accuracy and numerical prediction effectiveness, a general Community Radiative Transfer Model (CRTM) is used to simulate the brightness temperature of channels of the Atmospheric Infrared Sounder (AIRS) and analyze the effect of cloud parameters (cloud type, cloud moisture, cloud thickness and cloud top) on the brightness temperature of channels of AIRS. The results show that 1) Infrared radiation can be truncated by clouds, so that only the atmosphere above cloud top can affect the radiation; 2) The brightness temperature decreases gradually with the increase of water content, but its decrease rate will slow down until it is constant. The particles with a larger effective radius have stronger scattering for the radiation, so the corresponding brightness temperature will be lower; 3) For a constant cloud top height, the variation of cloud thickness will not affect the brightness temperature. For a constant cloud bottom height, the thicker the cloud is, the lower the brightness temperature will be; 4) Since the brightness temperature of ground channels are more sensitive to the variation of cloud top height, the brightness temperature of the channels above cloud top will not be changed.

Abstract:An algorithm combining Light of Sight (LOS) with the OpenGL software interface is proposed. The method uses the depth measuring and occlusion query functions of the OpenGL software interface to determine the effective emission surface in the detection direction and the transfer path of its radiation in mediums. Then, it uses LOS to obtain the radiation characteristics of the target in atmosphere in the detection direction. The simulation result shows that this algorithm is effective and has high computation efficiency.

Abstract:A small infrared target detection algorithm which combines target characteristics with class prediction of local background is proposed. The elimination of false alarms in the detection of small infrared targets in sky is studied in detail. In complex infrared scenes, the false alarms caused by complex and changing ground objects may seriously affect the sensitivity and robustness of a detection system. If the target characteristics are used alone, the false alarms caused by ground objects can be filtered difficultly. Firstly, the latent targets are extracted by using a new Top-Hat transform. Secondly, for each of the latent targets, the likelihood of being true targets is obtained from the target characteristics on the one hand, and another likelihood of true targets is obtained from the prediction of the class label (sky or ground) of the neighboring background on the other hand. Finally, both likelihoods are combined to eliminate the false targets. The experimental results show that compared with the algorithm which uses target characteristics alone, the detection performance of the proposed algorithm is improved greatly.

Abstract:To obtain more robust inversion models of Suspended Particular Matters (SPM) in water and reduce the influence of the modeling data error on the accuracy of an algorithm, six empirical, semi-empirical and semi-analysis models of single-band and corresponding band ratio parameters are used in the data sets measured in high turbidity water at Yangtze River estuary by different instruments in different cruises. The role of band ratio parameters in robustness improvement of the SPM inversion model is analyzed. The results show that the models using band ratio parameters have much higher accuracy than the corresponding single-band model. In the data sets obtained in May and December 2014, some single-band models are invalid with the highest accuracy no more than 0.5. However, the modeling accuracy of the corresponding band ratio models is about 0.8. In addition, when the models are used in the OLI images from Landsat 8, the validation accuracy of band ratio models is higher than that of the single-band models as well. The results confirm that the use of the band ratio parameters can enhance the robustness of inversion models when the SPM concentration is inverted in high turbidity water.

Abstract:With the rapid development of coal mine enterprises and the increasing complication of coal mine power systems in our country, the fault location and prediction of coal mine power systems become more difficult. Therefore, the realization of intelligent diagnosis of faults in mine power systems is very important. Most of faults in mine power systems have an important relationship with temperature. This relationship is embodied in the nonlinear mapping relationship between the temperature and its grey level in infrared images. In view of the poor contrast and unapparent details of infrared images of mine power systems, an infrared image enhancement algorithm based on Nonsubsampled Contourlet Transform (NSCT) is put forward. In the algorithm model, a nonlinear matching function is constructed. The function can be used to implement certain enhancement processing of the edge of an infrared image and suppress the interference of noises. The experimental results show that this method can implement intelligent diagnosis and location of the overheating faults in mine power systems and provide solutions for check.