改进LBP和HSV颜色直方图相结合的地表状态识别

在利用近地表遥感探测方法对地表信息进行反演时,地表状态的不同会导致电磁波传播方式不同,进而决定了所采取的遥感探测方式、探测波长及探测手段的不同。因此,地表状态的识别是进行近地表遥感反演的前提和基础,其识别的准确率也决定了反演结果的准确度。本文提供了一种改进LBP(local binary pattern)和HSV颜色直方图相结合的地表状态识别算法,通过改进阈值的LBP算法和HSV颜色直方图提取特征向量并建立判别条件,最后利用K邻近算法对测试样本与训练样本进行特征匹配,得到识别结果。将野外采集的411张图片多粗随机分组为训练样本和测试样本,结果表明206张测试样本的分类正确率都达98.7%以上,证明了本文算法的有效性。

Modified image analytical solutions for ground displacement using nonuniform convergence model

Based on the image theory,the analytical solutions of tunneling-induced ground displacement were derived in conjunction with the nonuniform convergence model.The reasonable value of Poisson ratio in the analytical solution was discussed.The ground settlement width parameter which could reflect the ground condition was introduced to modify the analytical solutions proposed above,and new analytical solutions were presented.To evaluate the validity of the present solutions using the nonuniform convergence model,the results were compared with the observed values for four engineering projects,including 38 measured data of ground settlement.The agreement shows that the present solutions using the nonuniform convergence model are effective for evaluating the tunneling-induced ground displacements.

RESEARCH ON AUTOMATIC FOG IDENTIFICATION TECHNOLOGY BY METEOROLOGICAL SATELLITE REMOTE SENSING

There is an urgent need for the development of a method that can undertake rapid, effective, and accurate monitoring and identification of fog by satellite remote sensing, since heavy fog can cause enormous disasters to China’s national economy and people's lives and property in the urban and coastal areas. In this paper, the correlative relationship between the reflectivity of land surface and clouds in different time phases is found, based on the analysis of the radiative and satellite-based spectral characteristics of fog. Through calculation and analyses of the relative variability of the reflectivity in the images, the threshold to identify quasi-fog areas is generated automatically. Furthermore, using the technique of quick image run-length encoding, and in combination with such practical methods as analyzing texture and shape fractures, smoothness, and template characteristics, the automatic identification of fog and fog-cloud separation using meteorological satellite remote sensing images are studied, with good results in application.

面向深空探测图像分割的群智能混合优化算法

深空探测任务中,探测器需要在复杂的地形区域着陆,因此在轨障碍的快速检测至关重要,而图像分割是在轨检测的关键过程之一。鉴于此,提出一种基于粒子群和灰狼混合优化的多级阈值图像分割算法。在寻优过程中,所提算法在考虑图像能量分布的情况下,针对不同场景通过改变种群初始条件来自定义阈值级数。在位置更新过程中,所提算法增加扰动算子来扩大全局搜索的范围,引入动态权重来平衡群体的全局搜索能力与局部搜索能力,从而提高寻优的速度和精度,完成图像分割。实验结果表明,相较于传统的群智能算法,所提算法表现出较好的搜索能力,在处理灰度直方图不呈现双峰的复杂图像问题上有明显改善。

Earthquake deformation field characteristics associated with the 2010 Yushu M_s7.1 earthquake

The spatial distribution and characterization of a heavily damaged area can be determined by studying surface ruptures of seismogenic faults.If the distribution of surface ruptures can be obtained shortly after they occur,then areas heavily damaged by an earthquake can be readily identified.The information can then be used as a guide for earthquake relief programs.In this paper,an intensity offset-tracking method applied to an ALOS PALSAR image is used to map the Yushu earthquake rupture and to identify the faults activated by the earthquake.Azimuthal displacement analysis indicates that the surface rupture is about 55 km long,running from the epicenter to the southeast,trending N310°W,with a relative displacement of～1 m characterized by sinistral slip.The result of range displacement observations indicates that the north wall of the fault is dominated by decreases(i.e.,uplift in line of sight observations) ,whereas in the south wall of the fault,the range displacement is dominated by increases(drops in line of sight observations) .Given the position from which the images were recorded,this means that the north wall moves westward,and the south wall move eastward,i.e.,left-lateral slip motion across the fault.Finally,an earthquake disaster assessment using computer-assisted image analysis software shows that buildings near the fault rupture have been destroyed most heavily;therefore,the shape of the heavily damage belt is controlled partially by the fault rupture's geometry and the damage degree relates to the magnitude of displacement field.

Wedge tectonics in South China:constraints from new seismic data

Collisional orogens form when tectonic forces amalgamte fragments of Earth’s continental lithosphere.The sutures between individual fragments,or terranes,are potential sites of weakness that facilitate subsequent continental breakup.Therefore,the lithospheric architecture of collisional orogens provides key information for evaluating the long-term evolution of the continental interior:for example,the South China Block(SCB),where the tectonic history is severely obscured by extensive surface deformation,magmatism,and metamorphism.Using new passive-source seismic models,we show a contrasting seismic architecture across the SCB,with three prominent crustal dipping structures across the Jiangnan Orogen.Combined with constraints from multi-disciplinary regional geophysical datasets,these pronounced dipping patterns are interpreted as relict wedge-like lithospheric deformation zones initiated in the fossil collisions that assembled the Yangtze Block and the SCB.The overall trend of these tectonic wedges implies successive crustal growth along paleo-continental margins and is indicative of northward subduction and docking of accretional terranes.In contrast,no such dipping structures are preserved in the Cathaysia Block,indicating a weak and reorganized lithosphere.The variations in the deformation responses across the SCB reflect the long-term modifications of the lithosphere caused by prolonged collision and extension events throughout the tectonic history of the SCB.Our results demonstrate the critical roles that suture zones played in the successive growth and evolution of the continental lithosphere.