Abstract:As the important parameters for meteorological and climate research, temperature and water vapor profiles are of importance to the study of radiation transfer, vertical stability, convective available potential energy, precipitation and cloud formation and evolution. At present, the main remote sensing techniques for detecting temperature and water vapor profiles include laser radars, microwave radiometers and hyper-spectral resolution detectors. The instruments and algorithms for temperature and water and vapor profile retrieval by ground-based infrared hyper-spectral remote sensing are summarized. The basic principles of statistical retrieval algorithms and physical retrieval algorithms are presented emphatically. The technical features of different algorithms in retrieval accuracy, stability and computing time are analyzed in detail. Finally, the limitation and future trend of the current atmospheric temperature and water vapor profile retrieval by infrared hyper-spectral remote sensing are discussed.

Abstract:The influence of calibration methods on the radiation measurement precision of a passive Fourier Transform InfraRed (FTIR) spectrometer is studied by an MR-254 FTIR spectrometer from BOMEN Corp.. Taking a high temperature blackbody in the temperature range 50℃ to 1000℃ and a ultra high temperature blackbody in the temperature range 300℃ to 1700℃ as the standard radiators, the spectrometer is calibrated by using linear and nonlinear multipoint calibration methods respectively. The results show that the nonlinear multipoint calibration method is more accurate than the linear multipoint calibration method. The average relative difference between the calibrated radiation spectra and the theoretical radiation spectra is within 0.6%.

Abstract:The comprehensive analysis based on multi-source satellite data, especially the microwave quantitative products, is the inevitable trend of typhoon monitoring using satellite remote sensing in the future. More objective comprehensive typhoon position and intensity determining technique is helpful to the overall improvement of typhoon intensity prediction. Taking the severe typhoon `FITOW' in 2013 as an example, the typhoon location and intensity determination results issued by several tropical cyclone forecasting organizations at home and abroad including the National Meteorological center of China (NMC/CMA), Shanghai Meteorological Bureau (SMB), Japan Meteorological Agency (JMA), Guam, National Oceanic and Atmospheric Administration (NOAA), National Environmental satellite Data and Information Service (NESDIS) and Cooperative Institute for Meteorological Satellite Studies (CIMSS) and the possible causes for the differences in issued results are compared and analyzed in detail. The analysis results show that the path prediction results issued by the above organizations are relatively consistent. The path prediction results in the daytime are more reliable than those at night. The wind speed prediction results issued by NMC, SMB, Guam and Regional and Mesoscale Meteorology Branch (RAMMB) are close to each other. The results from NMC have the least error and the highest accuracy. The results from SMB, Guam and RAMMB are in the second place. The results from CIMSS are most unstable. The results from JMA have a lower error on the whole. This analysis is of referential value to the typhoon prediction servicemen on duty.

Abstract:The extraction of image edge features is very important in the processing of images. Compared with the corner information, the edge information contains richer representation mean of the target to be observed. It is of significance to the accurate extraction of target contour. With the improvement of detector's resolution and the increase of data update rate, development of the algorithms for fast and effective edge extraction has been one of the research hotspots. The technique for implementing high-precision image processing algorithms using FPGA is studied emphatically. The basic image processing operations such as Gaussian filter, sobel operator and non-maxima suppression are implemented by using the unique parallel pipeline processing mechanism of FPGA.

Abstract:In an infrared scene simulation system based on a Digital Micromirror Device (DMD), digital infrared scene signals are required to be used as the input source for modulating and controlling the DMD. To meet this requirement, a general digital infrared scene generation method is proposed. Firstly, the process of infrared scene simulation based on Vega by a computer is presented. Then, the design process of developing an infrared scene driving program and a scene format conversion program is described in detail. The method not only can convert the Vega infrared scenes into the static infrared images in BMP format and the dynamic infrared video in AVI format, but also can improve the reuse and portability of infrared scenes. Therefore, it is of great practical value to engineering applications.

Abstract:A medium and short distance, high speed and high precision pulse laser scanner which meets the first level of laser safety is designed for traffic data collection. To solve the problem of the laser scanner in rapid and high precision ranging, a digital full waveform pulse detecting method is proposed. The method judges the arriving time of the laser pulse by fitting the front edge of the laser pulse waveform. Taking the sampling clock of an Analog Digital Converter (ADC) as a counter, the delay of the laser echo signal is calculated. Then, according to the intensity of the laser echo signal, the ranging result is compensated. Thus, the Walk error is reduced greatly. The signal processing of the laser scanner is implemented on the basis of the high speed ADC and FPGA. The test results show that the laser scanner has its ranging frequency of 50000 points/s and its single point measuring precision is ±4 cm. It can meet the data collection requirements of automatic vehicle recognition, traffic flow investigation and passenger density detection.

Abstract:As a carrier of the optical elements in a space camera, the main supporting structure of the space camera plays a decisive role in making the relative positions of optical elements accurate and stable for a long time. Because of the advantages of high specific stiffness and high thermal stability, high volume SiC_p/Al composites are very suitable for making opto-mechanical structures for space application. Since the ultrasonic-aided brazing technique can solve the welding problem of high volume SiC_p/All composites, it has laid a foundation for the application of high volume SiC_p/Al composites in the main supporting structures of space cameras. A main supporting structure for a certain space camera based on high volume SiC_p/Al composites is presented. The mechanical properties of two similar main supporting structures made of TC4 and high volume SiC_p/Al composites respectively are analyzed. The results show that the weight of the main supporting structure made of high volume SiC_p/Al composites decreases by 31.8% and the first-order frequency increases by 25%. It is known in the mechanical and thermal tests that the main supporting structure meets the requirements in weld strength and size stability.

Abstract:According to the distribution characteristics of ship targets in infrared images, the approximate locations of ships are determined first through sea-sky line/coastline detection and the Regions of Interest (ROIs) of the ship targets are determined by utilizing the area characteristics of the targets. The sea-sky line/coastline is detected by using median filtering, Canny edge detection and Hough transform methods and the sea-sky line/coastline area is delineated. Then, the ROIs are determined according to the area characteristics of the ships. The algorithm is implemented by Vc programming. The results show that this method is simple and intuitive and can be used to determine the ROIs of ship targets near shore effectively.