Abstract:The optical parameters of optical components for a space optical remote sensor are usually determined by the experience of a designer. By establishing a full damping dynamic analysis model for a space optical remote sensor, the expressions of dynamic response of optical components are obtained. In view of the actual engineering condition, the dynamic response of the optical components is analyzed numerically through MATLAB programming when a damp ratio is 0.03 and a mass ratio is 0.2. The result shows that to keep the dynamic response of an optical component as low as possible, a reasonable frequency should be selected rather than increasing the dynamic response of the optical component subassembly blindly.

Abstract:Laser is susceptible to weather when it is propagating in atmosphere. This is because the severe weather including rain, snow and fog has a great attenuation function to laser and may cause the communication to be poor. So, it is necessary to analyze the transmission effect and attenuation characteristics of laser under different weather conditions. According to the experience relations of water content and visibility in radiation fog and advection fog, the formulas for calculating the transmission attenuation of laser in atmosphere under the fog weather condition are analyzed. Three typical empirical models for fog attenuation are simulated numerically by Matlab and the relationship of the visibility in fog with the attenuation coefficient of laser is obtained.

Abstract:Because of the features of high interference immunity and all-weather operation, the infrared imaging technology is widely used in various fields. A pseudo-color enhancement display method based on histogram equalization is proposed. The method includes two steps: image enhancement and pseudo-color processing. First, the mean value of an image is calculated. A different special transform method is used according to the mean value. Then, the histogram is equalized. In the process of pseudo-color processing, new pseudo-color coding tables are designed and are used for the pseudo-color processing and display of the enhanced image. The test result shows that after the processing of pseudo-color enhancement, the display effectiveness, dynamic range and details of the image are improved obviously.

Abstract:Recently, the Consultative Committee for Space Data System (CCSDS) has released its CCSDS 123.0-B-1 standard officially. This standard is a general international standard for lossless and near lossless compression of hyperspectral images. To reduce the storage capacity of image data, decrease the data transmission bandwidth, increase the data transmission rate and implement the data transmission in real time, the newest CCSDS algorithm standard is presented in brief and is used to solve the large capacity problem of hyperspectral images. The FPGA-based logic implementation of this algorithm includes the logic description of both a predictor and a encoder. Finally, the lossless compression simulation of hyperspectral images based on FPGA is given. Its compression property is compared with that of the JPEG-LS algorithm. The result shows that the CCSDS compression algorithm can meet the requirement of compression ratio of 2:1 for hyperspectral images.

Abstract:The selection of wavelength points and modeling methods is very important for the establishment of predictive analysis model in near infrared spectroscopy. On the basis of the traditional correlation coefficient method, a correlation coefficient threshold optimization method based on the genetic algorithm is proposed. In the method, the determination coefficient is maximized so as to find the optimal threshold. A radial basis neural network is used to establish a calibration model and an orthogonal least square method is used to select the center for modeling. The new method is used to predict the dimethy carbonate content in gasoline and its result is compared with the experimental result of the partial least square method. The result shows that the new method has a better prediction accuracy. Its determination coefficient is up to 0.9993.

Abstract:Infrared spectral detection methods such as the KBr powder method, specular reflection method, diffusion method and infrared microscope method which are commonly used in antique jade appraisal are presented systematically. The application of each method in antique jade appraisal is explained and their advantages and disadvantages are compared. In view of the identification of jade kinds, abrasive machining residual and antique jade alerting and the relation of alteration to jade quality, the applications of the infrared spectral detection method in jade appraisal are illustrated.