Abstract:Arsenic doped HgCdTe is the key material in the development of infrared devices including high performance infrared detectors, infrared focal plane arrays and p-on-n heterojunctions. In this work, references about arsenic doped HgCdTe are summarized. The activation of As is related to the annealing condition and the dopant concentrations. For doping concentrations in the 10₁₆-10₁₈cm_-3 range, a two-step annealing produces activation of As of the frontside HgCdTe. The V_Hg concentration is high relative to the backside HgCdTe .There exist As_Te and As_Hg in the space region close to the substrate.

Abstract:Because infrared images usually have the disadvantages of low contrast, blurry edge, low signal-to-noise ratio (SNR) and less gray levels, an improved infrared image enhancement algorithm based on histogram equalization is proposed. Firstly, by adaptively selecting an proper threshold, the redundant gray levels which have pixel sum less than the threshold are completely compressed and those effective gray levels which have pixel sum greater than the threshold are stretched on the basis of a very rational logarithm transformation. Secondly, a conventional histogram equalization method is used to process the stretched gray levels. Finally, all these equalized gray levels are arranged at an equal distance in the whole gray level area. To meet the real-time requirement, an infrared image enhancement system which uses a TMS320DM642 chip as its core processor is designed. The experimental result shows that the image enhanced by using this algorithm is obviously better than the one enhanced by using the conventional histogram equalization algorithm in quality. The object-background contrast and definition of the image are both improved and the edge details are kept. Moreover, it takes only 16.73 ms for the algorithm to process an image with $320\times256\times8$ bits. So, the requirement of real-time image processing can be satisfied completely.

Abstract:A non-uniformity correction algorithm based on neural network for infrared focal plane arrays (IRFPA) is proposed. Firstly, a normalized idea is used to process an image so as to choose a proper interactive step. Then, the structure of the hidden layer is optimized to obtain the desired signal more close to the real signal. The experimental result shows that the proposed method is better than the traditional neural network correction algorithm in correction precision, convergence rate and stability.

Abstract:Since the stars which can be detected by a star sensor in the daytime is limited, the demand of star navigation is limited severely. By using an infrared waveband, enough stars can be detected for navigation. Several near infrared multiple field-of-view detectors with a small diameter are used to detect the stars in different sky areas. Because the background radiation received by each detector is different, the detected stellar apparent magnitude is different. The MODTRAN software is used to analyze the background radiation detected by the detectors at different azimuths in the daytime. According to the radiation curves obtained at different azimuths, a background correction method, the reflection method is proposed and is verified by using six stars.

Abstract:Due to the complex optical properties of case II water, the application and inversion accuracy of water color remote sensing data can be reduced in the study of ocean water color remote sensing. The effect of relative spectral response and bandwidth of MODIS and TM channels on the water-leaving reflectance of optically complex case II water is analyzed. The analysis result shows that the effect of the relative spectral response and bandwidth of MODIS channels on water-leaving reflectance is much less than that of the corresponding TM channels. In addition, the quantitative analysis result shows that the relative spectral response and the bandwith have their different effect on the water-leaving reflectance of different channels and water types. According to three typical types of water at the mouth of Yangtze River, the water-leaving reflectance of the TM channels is used to simulate the reflectance of the entire channels. Thus, the spectral properties of case II water are characterized more obviously and the effect of the spectral response function and bandwidth is removed.

Abstract:After the basic principle of infrared thermal wave nondestructive detection and a heat transfer model are analyzed, a nonlinear parameter fitting method based on an infrared heat transfer model is proposed. The method is compared with the traditional polynomial method. The experimental result shows that its effectiveness is better than that of the common low-order polynomial fitting. In addition, for the same fitting effectiveness, the new method has less parameters and higher storage and compression rates. It is a promising processing method for infrared thermal image data.

Abstract:By using the hyperspectral remote sensing technology, phosphorus content of apple tree canopy could be estimated. The hyperspectral reflectance of apple tree canopy during spring shoots stopping growth period was measured using ASD FieldSpec 3 field spectrometer. Process spectral data in a variety of transformation forms，and find out significant spectrum parameters correlated with phosphorus content with correlation analysis. Through the regression analysis, establish estimating models of phosphorus content. The result showed that, near-infrared band is the sensitive band of phosphorus content of apple tree canopy. Band 808nm, 921nm, 1195 nm and 1272nm and the normalized infrared spectra index combined by these bands have a highly correlation with phosphorus content of apple tree canopy. All of the seven constructed estimating models could predict phosphorus content of apple tree canopy precisely. Among these estimating models, the model with Rnir(808, 921),Rnir(1195, 1272)as the independent variables and the model with R808,R921,R1195,R1272as the independent variables were determined as the best for phosphorus content prediction of apple tree canopy. This study will provide theoretical basis for rapid apple tree canopy phosphorus content prediction and nutrition diagnosis.