基于灰度级分组的X光行李图像增强改进方法

针对低对比度X光手提行李图像在机场安检中容易产生高虚警或高漏警的问题,提出了一种基于灰度级分组的X光行李图像增强改进方法。首先应用离散小波变换对低、高能图像进行融合,然后通过分频处理得到低、高频图像,再分别采用基本灰度级分组和可选择灰度级分组方法实现增强。将本文方法与基于灰度级分组的增强方法、传统的直方图均衡方法进行比较,实验结果表明,本文方法能够有效地改善图像质量,提高图像的清晰度。     

强度关联遥感成像技术

过去十多年中,利用光场的量子（或经典）涨落及其关联获取目标图像信息的量子（强度）关联成像技术和基于自适应稀疏结构表象的信号处理技术的不断发展,为图像信息的获取提供了一条可突破传统光学成像技术图像分辨率和图像获取效率理论极限的全新技术途径。文章将概括地介绍这一研究方向,并简要讨论其在遥感领域中的应用前景和需要进一步研究的...     

无损检测技术在姿控发动机总装中的应用探析

阐述了目视检测、射线照相检测、泄漏检测等三种无损检测技术在姿控发动机上的应用情况。重点介绍了泄漏检测技术,针对发动机的结构特点、不同系统的性能要求及总装接头连接处各种密封形式在装配测试中分别采用了浸泡法、皂泡法及氦质谱简易包封积累法等不同的泄漏检测技术。经过对几种泄漏检测方法的对比分析,得出了针对不同的系统性能要求。需要采用不同的泄漏检测方法来满足设计要求的结论。     

红外成像导引头抗干扰技术研究

红外成像制导是红外制导技术发展的趋势,在未来战争中将发挥重要作用。介绍了红外成像导引头的优缺点及其简单工作过程,重点分析了红外成像导引头针对不同的干扰源所采取的相应对抗措施,总结出了红外成像导引头的发展趋势是向着焦平面、智能化、通用化以及多模复合制导等方向发展。     

机动目标的ISAR回波信号模拟方法

针对逆合成孔径雷达(ISAR)的小转角目标回波特点,提出通过快速生成包络和相位的方法来构成目标回波.根据ISAR的成像原理,忽略包络延迟中由转动生成的分量和相位变化的弱小分量,降低了计算复杂度.对于由多个散射点构成的机动目标,只加入影响较大的偏航运动,运算量得以减小.模拟机动目标回波的成像结果证明了该方法的有效性.     

High resolution science with high redshift galaxies

We summarize the high-resolution science that has been done on high redshift galaxies with Adaptive Optics (AO) on the world’s largest ground-based facilities and with the Hubble Space Telescope (HST). These facilities complement each other. Ground-based AO provides better light gathering power and in principle better resolution than HST, giving it the edge in high spatial resolution imaging and high resolution spectroscopy. HST produces higher quality, more stable PSF’s over larger field-of-views in a much darker sky-background than ground-based AO, and yields deeper wide-field images and low-resolution spectra than the ground. Faint galaxies have steadily decreasing sizes at fainter fluxes and higher redshifts, reflecting the hierarchical formation of galaxies over cosmic time. HST has imaged this process in great structural detail to z  6, and ground-based AO and spectroscopy has provided measurements of their masses and other physical properties with cosmic time. Last, we review how the 6.5 m James Webb Space Telescope (JWST) will measure First Light, reionization, and galaxy assembly in the near–mid-IR after 2013.     

Current status of X-ray spectrometer development in the SELENE project

The X-ray spectrometer (XRS) on the SELENE (SELenological and ENgineering Explorer) spacecraft, XRS, will observe fluorescent X-rays from the lunar surface. The energy of the fluorescent X-ray depends on the elements of which the lunar soil consists, therefore we can determine elemental composition of the upper most lunar surface. The XRS consists of three components: XRF-A, SOL-B, and SOL-C. XRF-A is the main sensor to observe X-rays from the lunar surface. SOL-B is direct monitor of Solar X-ray using Si-PIN photodiode. SOL-C is another Solar X-ray monitor but observes the X-rays from the standard sample attached on the base plate. This enables us to analyze by a comparative method similar to typical laboratory XRF methods. XRF-A and SOL-C adopt charge coupled device as an X-ray detector which depletion layer is deep enough to detect X-rays. The X-ray spectra were obtained by the flight model of XRS components, and all components has been worked well to analyze fluorescent X-rays. Currently, development of the hardware and software of the XRS has been finished and we are preparing for system integration test for the launch.     

基于圆球与椭球的地球敏感器地心矢量算法分析

红外成像敏感器代表了新一代敏感器的发展方向。本文介绍了红外成像敏感器光学系统工作原理,对红外成像敏感器光学系统进行简化,利用小孔模型完成了对敏感器光学系统的建模,分别在地球球形模型和旋转椭球模型下进行了地心矢量推导和计算,获得了焦平面内地平圆盘的相关参数的具体表达式,用牛顿迭代法对地心距进行数值计算,比较分析了球形模型与椭球模型在求解地心距精度上的差别,分析了敏感器测量误差对地心矢量精度的影响,以及焦平面内地平圆盘各参数分别对地心距计算精度的影响程度。     

星载SAR海洋特征检测技术初步研究

以舰船尾迹检测为例,分析了星载SAR对海洋特征成像的机理,从理论上阐述了星载SAR在舰船尾迹检测中具有的独特优势。在此基础上建立了星载SAR对海洋特征成像的仿真模型,并给出了仿真得到的舰船尾迹SAR图像。