A novel method for destriping of OCM-2 data and radiometric performance analysis for improved ocean color data products

Despite the capability of Ocean Color Monitor aboard Oceansat-2 satellite to provide frequent, high-spatial resolution, visible and near-infrared images for scientific research on coastal zones and climate data records over the global ocean, the generation of science quality ocean color products from OCM-2 data has been hampered by serious vertical striping artifacts and poor calibration of detectors. These along-track stripes are the results of variations in the relative response of the individual detectors of the OCM-2 CCD array. The random unsystematic stripes and bandings on the scene edges affect both visual interpretation and radiometric integrity of remotely sensed data, contribute to confusion in the aerosol correction process, and multiply and propagate into higher level ocean color products generated by atmospheric correction and bio-optical algorithms. Despite a number of destriping algorithms reported in the literature, complete removal of stripes without residual effects and signal distortion in both low- and high-level products is still challenging. Here, a new operational algorithm has been developed that employs an inverted gaussian function to estimate error fraction parameters, which are uncorrelated and vary in spatial, spectral and temporal domains. The algorithm is tested on a large number of OCM-2 scenes from Arabian Sea and Bay of Bengal waters contaminated with severe stripes. The destriping effectiveness of this approach is then evaluated by means of various qualitative and quantitative analyses, and by comparison with the results of the previously reported method. Clearly, the present method is more effective in terms of removing the stripe noise while preserving the radiometric integrity of the destriped OCM-2 data. Furthermore, a preliminary time-dependent calibration of the OCM-2 sensor is performed with several match-up in-situ data to evaluate its radiometric performance for ocean color applications. OCM-2 derived water-leaving radiance products obtained after calibration show a good consistency with in-situ and MODIS-Aqua observations, with errors less than the validated uncertainties of ±5% and ±35% endorsed for the remote-sensing measurements of water-leaving radiance and retrieval of chlorophyll concentrations respectively. The calibration results show a declining trend in detector sensitivity of the OCM-2 sensor, with a maximum effect in the shortwave spectrum, which provides evidence of sensor degradation and its profound effect on the striping artifacts in the OCM-2 data products.     

北斗RDSS用户机测试系统关键技术研究

为了实现对北斗RDSS用户机检测的需求，研制了专用测试系统。介绍北斗RDSS用户机测试系统的基本组成和工作原理，分析了测试系统研制涉及到的部分关键技术：系统建模仿真、RDSS出站信号模拟、RDSS入站信号接收、入站信号质量分析等，最后列举了所研制的测试系统到达的主要技术指标。     

连铸生产过程中提高拉坯速度的措施

针对连铸生产过程中提高拉坯速度时存在的问题,提出了发展高速连铸技术的重要意义。讨论了实现高速连铸的关键技术。     

多元协方差控制图

论述了多元正态分布情形下建立基于样本广义方差│Ｓ│的多元协方差控制图的方法,叙述了分布参数∑已知时Ａｌｔ建立的多元协方差控制图－│Ｓ│图方法,给出了∑未知时建立多元协方差控制图－△图的方法,给出了按两步法建立∧图的步骤,解决了利用样本广义方差建立多元协方差控制图问题,文中还给出了两个应用实例加以说明。     

关于一种人-机闭环品质评价方法的分析

运用结构驾驶员模型研究人-机闭环系统,根据Hess建立的衡量任务完成难易程度的模型和驾驶员的评价函数,拟定了飞行品质的计算方法.针对2个被控对象模型进行了飞行品质的计算.分析了驾驶员剩余、系统输入、大气紊流以及驾驶员模型参数变化对驾驶员评价品质的影响,以便更透彻理解和揭示Hess提出的操纵品质评价指标的内涵,这对飞机设计应用具有实际意义.      

构建“突出数字”的教学体系 创新“强化实践”的实验方法

本文是对《电工学〈电子技术〉》课程的改革与实践的总结,主要介绍了＂强化数字,突出集成,注重实践＂的模块化教学体系和阶梯式实验方法。     

轻小型高光谱成像仪前置望远系统设计

轻小型、高分辨率已经成为高光谱成像仪的发展趋势。文章基于Offner型光谱成像系统的结构特点,分析了高光谱成像仪前置望远系统的设计特殊性,利用同轴反射系统的几何光学理论求解方法,给出了一种长焦距、大视场的高光谱成像仪前置望远离轴三反远心系统的设计思路和设计结果,光学系统焦距2 500 mm,视场角达到12°。分析表明,该设计在奈奎斯特频率71.4线对/mm处调制传递函数接近衍射极限,结构紧凑,不仅适用于Offner型光谱仪前置望远光学系统,还可用于其它大视场远心光学系统。     

高职高专教学质量保障现状及对策研究

作为高等教育主力军的高职高专教育,其教学质量直接关系到国民高等教育的质量和水平,并因其职业性的特点,在很大程度上决定了社会的生产发展速度。因此,探寻在现有教育资源的基础上如何保证高职高专教育的有效性,成为高职高专教育的长期发展的根本保证。     

专科学生英语学习动机研究

学习动机与学生的学习态度、学习策略及学习成绩是紧密相关的。它直接制约着学习的积极性,极大地影响着学生的外语学习效果。本文介绍了对大学生英语学习动机研究的过程及其教学启示。     

复合材料层合板结构制造工艺的质量控制

介绍了复合材料成型特点以及制造工艺的质量控制,为了清楚地说明工艺质量控制问题,将工艺分为成型和固化两个阶段,并对每个阶段分别进行分析,特别关注影响产品质量的工艺参数。为复合材料制造工艺的质量控制和复合材料的适航审定提供了依据。