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991.
针对地面激光雷达点云和数码光学影像非同源异质数据自动配准困难的问题,本文提出了基于互信息的两种数据同名特征高精度自动提取的方法。首先,把点云数据生成中心平面投影的反射强度图像和基于RGB信息的彩色图像,应用点云彩色图像和数码光学影像的匹配,确定点云与影像的粗配准参数;然后,对反射强度图像进行特征提取,应用粗配准参数确定其在数码光学影像上的初始位置,应用互信息实现非同源数据的高精度匹配;最后,应用罗德里格矩阵和选权迭代方法计算高精度配准参数,生成三维彩色模型。试验证明,本文方法可以解决地面激光点云和数码光学影像非同源异质数据的配准问题,具有一定的研究和应用价值。 相似文献
992.
993.
国际地球参考框架的最新版本已将测站非线性变化纳入模型之中,然而目前最优的顾及测站非线性变化的地球参考框架建立方式仍有待深入研究。首先重新处理了全球分布的全球定位系统测站2004−2016年的观测数据,获取了自洽精确的基础数据;然后改正了13个CMONOC(crustal movement observation network of China)基准站的震后形变,分别建立了基于函数模型的FREQ2016以及顾及环境负载改正的GFZ2016和EOST2016地球参考框架;最后通过对比分析模型拟合度、速度场和周期性信号,探讨了目前最优的顾及测站非线性变化的地球参考框架建立方式。结果表明,FREQ2016的验后残差WRMS(weighted root mean square)平均值最小;FREQ2016测站季节性信号更为显著,尤其是半周年信号;三者的水平速度差异可以忽略(< 0.08 mm/a),个别测站垂向速度差异较大,最大可达1.3 mm/a,FREQ2016水平速度场的形式误差减小约10%。因此,目前基于函数模型的建立方式优于顾及环境负载改正的建立方式。
相似文献994.
995.
Hajime Naruse Shigehiro Fujino Apichart Suphawajruksakul Thanawat Jarupongsakul 《Island Arc》2010,19(3):399-411
Multiple‐layered tsunami deposits have been frequently reported from coastal stratigraphic sequences, but the formation processes of these layers remain uncertain. A terrestrial sandy deposit formed by the 2004 Indian Ocean Tsunami was investigated at Ban Nam Kem, southern Thailand. Four internal layers induced by two tsunami waves were identified in the tsunami deposit. Sedimentary structures indicated that two units were formed by run‐up currents caused by the tsunami and the other two units were deposited by the backwash flows. Graded bedding was common in the layers, but inverse grading was observed at limited intervals on the surveyed transects. The characteristics of the multiple‐layered tsunami deposit vary remarkably over a very short distance (<1 m) in response to the local topography. Remarkable asymmetries in thickness and grain‐size distribution are recognized between the run‐up and backwash flow deposits. On the basis of the interpretation of sedimentary structures, the formation process of the multiple‐layered tsunami deposit observed in this study can be explained in a schematic model as the modification of the ideal tsunami sequence by local erosion and the asymmetric hydraulic properties of tsunami waves, such as the maximum shear velocity and the heterogeneity of the flow velocity field. 相似文献
996.
伸展背景下陆相地层发育的控制:以阜新盆地为例 总被引:2,自引:0,他引:2
陆相地层发育普遍雠为是受构造控制的,然而在构造背景下,其它控制因素如水位或水量,沉积物供给量等是如何起作用的呢?根据Schilsche的伸展盆地定量充填模型,模拟阜新盆地沙海组和阜新组地层的形成,得出一些陆相地发育控制的一些认识。在陆相地层发育过程中,层序发育与沉积环境转化是受盆地的构造沉降与可容空间,沉积物供给与沉积物堆积速率,盆地供水量与气候以及沉积作用过程的影响和控制。 相似文献
997.
Cyclic terpenoids of contemporary resinous plant detritus and of fossil woods, ambers and coals 总被引:3,自引:0,他引:3
Bernd R.T. Simoneit J.O. Grimalt T.G. Wang R.E. Cox P.G. Hatcher A. Nissenbaum 《Organic Geochemistry》1986,10(4-6)
Cyclic terpenoids present in the solvent extractable material of fossil woods, ambers and brown coals have been analyzed. The sample series chosen consisted of wood remains preserved in Holocene to Jurassic sediments and a set of of ambers from the Philippines (copalite), Israel, Canada and Dominican Republic. The brown coals selected were from the Fortuna Garsdorf Mine and Miocene formations on Fiji.The fossil wood extracts contained dominant diterpenoid or sesquiterpenoid skeletons, and aromatized species were present at high concentrations, with a major amount of two-ring aromatic compounds. Tricyclic diterpenoids were the predominant compounds in the ambers. Aromatized derivatives were the major components, consisting of one or two aromatic ring species with the abietane and occasionally pimarane skeletons. The saturated structures were comprised primarily of the abietane and pimarane skeletons having from three to five carbon (C1, C2, etc.) substituents. Kaurane and phyllocladane isomers were present in only minor amounts. Bicyclic sesquiterpenoids as saturated and partial or fully aromatized forms were also common in these samples, but only traces of sesterterpenoids and triterpenoid derivatives were found.The brown coal extracts were composed of major amounts of one- and two-ring aromatized terpenoids, with a greater proportion of triterpenoid derivatives than in the case of the woods and ambers. This was especially noticeable for the German coal, where the triterpenoids were predominant. Open C-ring aromatized structures were also present in this coal. Steroid compounds were not detectable, but some hopanes were found as minor components in the German brown coal.An overview of the skeletal structure classes identified in each sample, as well as the general mass spectrometric characteristics of the unknown compounds are included in the present paper. It can be concluded from these structural distributions that aromatization is the main process for the transformation of terrestrial cyclic terpenoids during diagenesis, constituting a general pathway for all terpenoids. 相似文献
998.
999.
鲁中山区五级构造单元莱芜凹陷、东平凸起及新甫山凸起分布有热水资源。研究发现,不同构造位置热水埋深、热储类型及成因机制不尽相同。利用鲁中山区各构造单元典型地热井测温数据,热水与其他类型水体水化学组分、同位素对比分析结果,对地热地质特征、热水成因及热储温度值进行研究和计算。结果表明,大气降水为鲁中山区热水补给来源;区内热水水化学类型为SO4-Na·Ca型及SO4·R-Na·Ca型(R为Cl或HCO3);较其他水体,地热水同位素δ18O和δD表现为贫化特征;各热储温度值低于100℃,属于中低温热储范畴,且热水均为未成熟水,表明地热水水-岩相互作用尚未达到离子平衡状态,溶解作用仍在进行,或热水受到了外源冷水的混合作用。位于盆地内部的冷家庄地热系统属于热传导型,盆缘凸起的安驾庄及桥沟地热系统属于热对流型。研究结果对鲁中山区地热水资源开发提供了理论依据。 相似文献
1000.
Richard David Williams Marie-Lou Lamy Georgios Maniatis Eilidh Stott 《地球表面变化过程与地形》2020,45(1):251-261
High-resolution quantification of fluvial topography has been enabled by a number of geomatics technologies. Hyperscale surveys with spatial extents of <1 km2 have been widely demonstrated by means of terrestrial laser scanning (TLS) and structure-from-motion (SfM) photogrammetry. Recent advances in the development and integration of global navigation satellite system (GNSS), inertial measurement unit (IMU) and lightweight laser scanning technologies are now resulting in the emergence of personal mobile laser scanners (MLS) that have the potential to increase data acquisition and processing rates by one to two orders of magnitude compared to TLS/SfM, and thus challenge the recent dominance of these technologies. This investigation compares a personal MLS survey using a Leica Pegasus Backpack that integrates Velodyne Puck VLP-16 sensors, and a multi-station static TLS survey using a Riegl VZ-1000 scanner, to produce digital elevation models (DEMs) and surface sedimentology maps. The assessment is undertaken on a 500 m long reach of the braided River Feshie. Comparison to 107 independent real-time kinematic (RTK)-GNSS check points resulted in similar mean error (ME) and standard deviation error (SDE) for TLS (ME = −0.025 m; SDE = 0.038 m) and personal MLS (ME = −0.014 m; SDE = 0.019 m). Direct cloud-to-cloud (C2C) comparison between a sample of TLS and personal MLS observations (2.8 million points) revealed that C2C distances follow a sharply decreasing Burr distribution (a = 2.35, b = 3.19, rate parameter s = 9.53). Empirical relationships between sub-metre topographic variability and median sediment grain size (10–100 mm) demonstrate that surface roughness from personal MLS can be used to map median grain size. Differences between TLS and personal MLS empirical relationships suggest such relationships are dependent on survey technique. Personal MLS offers distinct logistical advantages over SfM photogrammetry and TLS for particular survey situations and is likely to become a widely applied technique. © 2019 John Wiley & Sons, Ltd. 相似文献