Advanced fractal approach for unsupervised classification of SAR images

Unsupervised classification of Synthetic Aperture Radar (SAR) images is the alternative approach when no or minimum apriori information about the image is available. Therefore, an attempt has been made to develop an unsupervised classification scheme for SAR images based on textural information in present paper. For extraction of textural features two properties are used viz. fractal dimension D and Moran’s I. Using these indices an algorithm is proposed for contextual classification of SAR images. The novelty of the algorithm is that it implements the textural information available in SAR image with the help of two texture measures viz. D and I. For estimation of D, the Two Dimensional Variation Method (2DVM) has been revised and implemented whose performance is compared with another method, i.e., Triangular Prism Surface Area Method (TPSAM). It is also necessary to check the classification accuracy for various window sizes and optimize the window size for best classification. This exercise has been carried out to know the effect of window size on classification accuracy. The algorithm is applied on four SAR images of Hardwar region, India and classification accuracy has been computed. A comparison of the proposed algorithm using both fractal dimension estimation methods with the K-Means algorithm is discussed. The maximum overall classification accuracy with K-Means comes to be 53.26% whereas overall classification accuracy with proposed algorithm is 66.16% for TPSAM and 61.26% for 2DVM.     

飞机飞行航迹测试数据转换软件

:通过对飞机飞行航迹测试仪功能的分析 ,确定了测试数据转换成航迹相对于跑道中心实际坐标的基本原理 ,在此基础上编制了相应的软件。     

民航卫星通信网可视通信图像压缩编码方法研究

对民航卫星通信网进行可视通信图像压缩编码方法进行了研究。通过在多媒体计算机上进行模拟实验表明，将视频信息及语音信息压缩为64kbps通过TES卫星网传输方案是可行的。     

Use of the ASTER satellite images for evaluation of structural changes in the Popocatépetl volcano related to microseismicity

Mexico is one of the most volcanically active regions in North America. Volcanic activity in central Mexico is associated with the subduction of the Cocos and Rivera plates beneath the North American plate. Periods of enhanced microseismic activity, associated with the volcanic activity of the Popocatépetl volcano are compared with periods, during which the microseismic activity was low. We detected systematical changes in the number of lineaments, associated with the microseismic activity due to lineament analysis of a temporal sequence of high resolution satellite images of the Popocatépetl volcano, provided by the ASTER/VNIR instrument. The Lineament Extraction and Stripes Statistic Analysis (LESSA) software package was used for the lineament extraction. In the future it would allow develop a methodology for detection of possible elevation of pressure in volcano edifice.     

二维计算机图象检测系统

目前,利用机器视觉系统监测生产过程和进行质量控制是一个非常活跃的研究领域。当把视觉系统用于几何量测量时,必须解决其硬件的分辨力极限所带来的问题:测量精度高意味着测量范围小,或者,测量范围大意味着测量精度低。提出了解决上述问题的方法:一个由步进电机驱动的XY工作台与图象处理系统相结合。产生出一个多坐标系统结构。测量参数在两个坐标系之间传送,并在100mm×100mm范围内,在X和Y两个方向,达到的测量精度为0.02mm。     

一种用于ACSR的主从机并行处理系统

以微机、ＬＨ－ＳＣ１６Ａ型Ａ／Ｄ板、ＳＣ５０型Ｄ／Ａ板以及ＴＭＳ３２０Ｃ３０Ａ型ＤＳＰ板为基础，建立了时域结构响应主动控制的主从机并行处理系统。这一系统具有多通道快速运算能力，可提高控制系统的控制律，更新速率，改善控制系统的跟踪能力。     

“自准”赝像及识别

置平面镜于凸透镜后,则凸透镜前焦平面上的物成像于该物平面上,即“自准”成像.满足其它条件也能成像于物平面.分析不同条件下像的形成及其特点,并给出识别自准成像的判据.     

串行程序的并行划分算法及其正确性证明

针对多机系统结构，本文提出了在大粒度级并行划分串行程序的算示。该算法通过识别并行循环任务以及通过确定调用上下文关系识别过程任务，来划分串行程序中的并行成份。该算法是对串行程序实施并行分解的基础。本文还给出了该算法的正确性证明。     

一种基于视觉的微型飞行器姿态检测算法

探讨了基于视觉的微型飞行器的飞行状态检测方法，利用机载摄像头获得图像。根据某种准则识别出地平线，进而变换得到飞机的姿态角。文中给出了地平线判别准则及相应的算法和姿态角变换公式。最后，给出了一个实际算例及处理结果。     

高分影像辅助下的航空高光谱严密几何检校方法

 惯性测量单元(IMU)与传感器视准轴的偏心角和偏心矢量是造成航空线阵列高光谱数据几何校正误差的主要原因之一。在分析偏心角与偏心矢量误差来源之后提出该误差由IMU主轴与传感器主轴的角度偏差、测区固定偏差、GPS中心与传感器投影中心相对偏差组成,在此基础上建立了较为严密的检校模型。针对模型解算时需要大量高精度控制点的问题,提出了一种高分影像辅助下的亚像元精度控制点自动提取方法。通过多地区、多传感器高光谱航测实验表明,亚像元精度控制点能有效提高模型解算精度。新检校模型可获得亚像元校正精度,推扫式传感器——应用型机载成像光谱仪(AISA)建模中误差约为0.39个像元,摆扫式传感器——实用型模块化成像光谱仪(OMIS)建模中误差约为0.23个像元,校正后的影像可直接进行拼接。