Median filtering can effectively eliminate random noise, and the denoising effect of mean filtering on the Gaussian noise is significant. In the reheating furnace, these two noises coexist. The image pre-processing technology is used in the steel billet images of the furnace. Experiments show that this method maintains a good image detail during the noise removal.

To estimate the optical turbulence in the land surface layer usually needs the meteorological observations at two different layers, but the normal surface meteorological observations are carried out in only one layer. In order to estimate the optical turbulence in the land surface by using the meteorological observations only in one layer, a model was given based on the surface energy balance by using the Shapiro empirical scheme of the surface net solar radiation fluxes which uses the usual normal meteorological observations as input and the U. S. Army Unified Soil Classification Scheme. The soil temperature was first estimated based on the numerical solution of the thermal conduction equation, the surface temperature was then estimated by using the simulated first layer soil temperature based on the surface energy balance, and the surface humidity was estimated by using the forcing-restoration method. At last, the estimated surface temperature and humidity were taken as the temperature and humidity at the roughness height, and the optical turbulence was estimated based on the meteorological observations at the observation layer and the estimated temperature and humidity at the roughness height. It is found that the optical turbulence estimated by the model is generally consistent with those estimated by using the meteorology observations conducted at two different layers in the land surface.

Total atmospheric transmittance measurement equipment and calibration methods were described. Based on the existing research results, the total atmospheric transmittance collection procedures was developed and improved with Visual C++ 6.0, so that the equipment can automatically collect data. The atmospheric transmittance of stellar spectra with different types were measured using the total atmospheric transmittance measurement equipment, and the measured data were processed and analyzed, and the measurement value for six categories of stellar spectra at the upper bound of atmosphere were obtained. Based on the total atmospheric transmittance multi-objective calibration principle and the completion of calibration measurement for the major stellar spectral types, the equipment is able to carry out the real-time measurement of the total atmospheric transmittance.

In order to study backscattering and polarization properties of background aerosol over Hefei, routine observed data by polarization lidar in clear days from Jan. 1, 2007 to Feb. 2, 2009 are analyzed statistically. The results show that aerosol backscatter ratio and depolarization ratio in the middle and upper troposphere over Hefei vary obviously with season, the values of which are biggest in spring, take secondary place in winter, then in summer, least in autumn. In spring, the results show relatively larger values because of increased non-spherical particles. The analysis can provide useful reference for inversion of low troposphere lidar detection data and for research of aerosol layers (dust or pollution) in special weather conditions.

The size distribution and extinction characteristics of sand particles are investigated for three representative sand weathers, light dust, sand blowing and sand storm. The influence of the blowing on the number density of sand and dust particles is discussed. And the dust transport characteristics according to results measured by optical particle counter(OPC) and micro pulse lidar(MPL) are analyzed.

Based on wave radiation transmission theory in random medium and Monte-Carlo method, the optimum extinction characteristics of water fog in multiband is studied. The effect of incident wavelength and particle radium on the mass extinction coefficients of the water fog with lognormal distribution is numerically simulated. And the numerical results is compared with the document data. The transmittance of the laser in the mist is calculated, which is related to wavelength, the width of water fog and the number density. The results show that the multiple scattering must be considered when the number density is thick. The best screening effect can be obtained when the particle radium chosed is closed to the wavelength of the extincted laser. And transmission or reflectivity makes evaluation of the fog more convenient. It has theoretical reference value to the research of the screening performance on smoking.

The long-path differential optical absorption spectroscopy (DOAS) technique is used for monitoring HCHO, O3 and NO2 in Jiangmen City in the Pearl River Delta from Oct. 15 to Nov. 19, 2008. Combined with meteorological data, the analysis of major pollutants HCHO, O3, NO2 diurnal variation characteristics in Jiangmen City is made. At the same time, the main sources of pollution in Jiangmen City are analyzed. The correlation analysis and trend comparison of HCHO and other types of pollutants concentration data indicate that the source of HCHO in Jiangmen City comes mainly from secondary pollution. Results of multiple linear regression also confirm this conclusion.

The Tropical Rainfall Measuring Mission (TRMM) satellite has collected a plenty of radiances from global clouds and precipitation, providing invaluable datasets for parameter retrieval of clouds and precipitation, in which cloud detection undoubtedly plays a key role. A cloud detection scheme, available during daytime, was proposed relying on five-channel measurements from TRMM visible and infrared scanner (VIRS). Three kinds of pixels including clear-sky, mixed-cloudy and cloudy ones are separated by such a scheme, which contains three major steps, i.e., terrain recognition, two-dimensional table search and decision tree determination. A comparison was conducted specially with MODIS standard cloud products to verify the cloud detection. It was demonstrated that the accuracy of cloud detection is satisfied on the whole, especially for grounds that are not covered by snow and ice, with mean cloud fraction bias less than 5%. When applied to cases companied by snow and ice in winter and or over plateau area, the 1.6 m channel reflectivity information, combined with 3.7 m and 10.8 m channel BT, were used to identify snow and ice covered sky in this cloud detection scheme, which made snow-covered sky pixels and cloud pixels well separated. Therefore, the proposed cloud detection scheme can be used to TRMM VIRS with considerable reliance, which leads to great convenience for further application of associated TRMM multiple-sensor measurements.

The all-fiber Mach-Zehnder interferometer is an important interference device. The scattering matrix analysis method is adopted. The transmission characteristics of the all-fiber Mach-Zehnder interferometer are studied by using computer numerical simulation. The relationship between output spectrum and variations of optical structural parameters is obtained.

Generator of square waveform is important in designing, using and maintaining electrical equipment. The requirements of frequent precision and stabilization of the generator is increasing. Design of a generator based on the DDS and DSP chip is presented. In the design, DDS chip generates square waveform. DSP chip controls DDS chip to change the frequency and duty ratio. It is programmable and offers various communication interfaces. The design is adopted for the delay pulse generator of L625 lidar presently. It also can be useful for other equipments which need high-powered signal generator.

In the real-time atmospheric data collecting system, atmospheric data can be collected with multi-serial communication at the same time. Based on VC++6.0, how to use MSComm control to realize multi-serial communication is introduced. The procedure is depicted containing sending pretreatment datum from serial device RS232 to PC, and bringing the collection datum display, storage and transmission to come true. The scheme is simple and practical, and it is successfully used in the multi-serial interface real-time acquisition and processing system. The communication portion adopts UDP/IP.