Abstract:Because the nephograms of FY-2 meterological satellite show that there exists stray infrared light in the radiometer, it is necessary to further modify the optical system used in the radiometer so as to suppress the stray infrared light. The generation mechanism and path of the stray infrared light in the optical system are simulated and analyzed by the TracePro software. On the basis of the analysis result, several measures which can be used to suppress the stray infrared light of the optical system effectively are proposed. Finally, these measures are evaluated by calculating the Point Source Transmission (PST) function of the optical system.

Abstract:For optoelectronic detection systems such as an infrared scanning payload, the reduction of the Instantaneous Field of View (IFOV) is important for background cluster suppression, detection probability improvement and false alarm rate decreasing. An oversampling technique is always the research hotspot for the improvement of the imaging resolution of an imaging instrument. In view of a point target detection system, the normal sampling and oversampling techniques are compared with each other. The result shows that the oversampling technique has its obvious advantages in the respects of standard response deviation, average response and PEE.

Abstract:According to the practical project application of an infrared imaging system, the basic radiation calibration principle for nonuniformity correction of an Infrared Focal Plane Array (IRFPA) is presented. The mathematic mechanism in which the nonuniformity correction of an IRFPA belongs to function interpolation or fitting is derived. A nonuniformity correction algorithm suitable for project application is given. Meanwhile, to overcome the limitation of device shortages in the practical research work, the simulation technique for nonuniformity correction of an IRFPA is studied in detail and an effective simulation algorithm is given. The simulation technique can meet the validation and evaluation requirements of a nonuniformity correction algorithm in practical projects.

Abstract:To meet the objection identification need under a low-speed data chain, a coding strategy about a Region of Interest (ROI) is introduced into infrared video coding. On the basis of a H.264 video encoding/decoding framework, the ROI quantitative model is optimized by adding the processing of ROI encoding, constructing the video encoding/decoding framework and adjusting the quantitative parameters of ROI and non-ROI macroblocks in the bit rate control process. The experimental result shows that this method can save the limited bit rate, increase the details of ROI objects, improve the definition of ROI objects and improve the subjective visual quality on the whole.

Abstract:An infrared and low-level-light image fusion algorithm based on image sparse representation is proposed according to human visual systems and the over-complete sparse representation. In the method, an image is segmented into partly overlapped image patches firstly. The image patches are decomposed by an orthogonal matching pursuit algorithm. Then, the maximum fusion rule is used to choose suitable fusion coefficients for the reconstruction of image patches. Thus, the fused images are obtained. The experimental result shows that compared with the traditional fusion methods such as wavelet transform, Laplacian pyramid and principal component analysis methods, the proposed method has better fusion effectiveness.

Abstract:In the matching process of multi-sensor images based on features, the incomplete contour caused by imaging may increase the difficulty in image matching. To solve this problem, a novel image matching method based on block shape features is proposed. Firstly, the contour features are extracted from a reference image and a real-time image respectively and are divided into blocks hierarchically. Then, the block features are extracted and normalized. Finally, the weighted similarity measure is used to implement matching localization. Because the area information of a candidate target is used to exclude false alarms, the correctness and robust of the matching are further improved. The method is tested in the matching of infrared and visible images. The result shows that the proposed method has better matching performance for multi-sensor images.

Abstract:The solid waste and liquid generated in mining may leave heavy metal elements in soil and hence affect the growth of the crops in the mining area. By selecting Wansheng District in Chongqing as a research area, the measured hyperspectral data of sweet potato and pumpkin and the heavy metal content in the soil samples are collected. By analyzing the correlation of the heavy metal content in the soil with the red edge position of the crops, it is found that different heavy metal content in the soil has different effects on the main crops in the research area. The result shows that in the two main crops, the sweet potato is more sensitive to the heavy metal elements such as Cr, Mn and Cd while the pumpkin can absorb and counteract the above heavy metal elements in soil. This result can provide the theoretical basis for the selection of the crops to be planted in Wansheng District.

Abstract:To assess the shielding property of carbonyl iron material at terahertz wavelengths, the transmission spectra of reference samples, 0.5 mm carbonyl iron samples and 1 mm carbonyl iron samples were measured respectively by a Terahertz Time-domain Spectroscopy (THz-TDS). The analysis showed that with the increase of the thickness of the carbonyl iron samples, the pulse width of the terahertz time-domain spectrum would increase, its peak value would decrease and the frequency domain spectral range would be reduced. The carbonyl iron samples had their maximum shielding effectiveness of about 66 db. The wavelength ranges in which the 0.5 mm and 1 mm carbonyl iron samples had the shielding effectiveness greater than 66 db are those from 0.76 to 1.46 THz and from 0.49 to 1.48 THz respectively.

Abstract:The influence of back surface field of microcrystalline silicon on the a-Si(n)/c-Si(p)/uc-Si(p ) heterojunction solar cell is simulated with the afors-het software at different operation temperatures. The results show that the open circuit voltage and conversion efficiency increase with the increasing of the band gap of microcrystalline silicon. The open circuit voltage, fill factor and conversion efficiency increase with the increasing of the doped concentration. The cell performance declines when the microcrystalline silicon become thicker. The corresponding best values of doping concentration and thickness change a little when the operation temperature of the cell rises. However, the corresponding best value of band gap tends to move right obviously when the operation temperature of the microcrystalline silicon back surface field increases. The experimental results provide the experimental parameters for the commercial production of solar cells.