Direct Creation of Construction Drawings for Kwan-yin Statue by Close-Range Photogrammetry

In order to provide the model point accuracy of ±2 mm,an extra high accuracy industrial control net with four surveying piers with accuracy ±0.1 mm was set up around the model.Tens of orientation marks have been placed on the different parts and measured with accuracy ±0.2 mm from the above_mentioned piers.The main four stereopairs taken with the P31 camera around the model are simultaneously processed on the BC2 analytical plotter.The accuracy of absolute orientation is better than ±0.9 mm.Finally,about 300 sections construction drawings have been directly offered,and the close_range photogrammetric data has been used for the design and construction of the statue.

Determination Method for Shear Strength Parameters of Rock-Soil Mixtures Using Close-Range Photogrammetry and 3-D Limit Equilibrium Theory

Using a combination of close-range photogrammetry and three-dimensional(3-D) limit equilibrium theory, a determination method for the shear strength parameters of rock-soil mixture is presented. A close-range photogrammetry method is used for measurement of the 3-D terrain of the experimental target. Auto CAD Lisp and EXCEL VBA are used to perform 3-D limit equilibrium analysis of the stability of sliding mass and perform backanalysis of shear strength parameters. The presented method was used to determine the shear strength parameters of rock-soil mixtures at the Liyuan Hydropower Station. The 3-D terrain of sliding surface could be measured notably well using of closerange photogrammetry. The computed results reveal that the cohesion and friction angle of rock-soil mixtures were 3.15 k Pa and 29.88o for test A, respectively, and 4.43 k Pa and 28.30o for test B, respectively, within the range of shear strength parameters, as determined by field and laboratory tests. The computation of shear strength parameters is influenced by the mesh grid number, especially the cohesion of the rock-soil mixture. The application of close-range photogrammetry can reduce the siteworks and improve the computational efficiency and accuracy.

Characteristics and close-range exploration methods of near- Earth asteroid 2016HO_(3)

The characteristics of asteroids are vital parameters for planning asteroid exploration missions.These characteristics have been explored in close range for some typical asteroids,and are summarized in the article.This allows estimates of the characteristics of asteroid 2016HO_(3),the target of the first Chinese asteroid exploration mission,Tianwen 2.We obtain 80 characteristic parameters in 9 categories and analyze their impacts on the mission.By comparing three close-range exploration modes,we provide advantages and disadvantages of each,and propose suitable methods for the exploration of 2016HO_(3).Owing to the weak gravity and small size of 2016HO_(3),a combination of multiple hovering positions and active orbiting is recommended for scientific exploration.

Urban Geospatial Information Acquisition Mobile Mapping System based on close-range photogrammetry and IGS site calibration

The measurement accuracy of the Mobile Mapping System (MMS) is the main problem, which restricts its development and application, so how to calibrate the MMS to improve its measure-ment accuracy has always been a research hotspot in the industry. This paper proposes a position and attitude calibration method with error correction based on the combination of the feature point and feature surface. First, the initial value of the spatial position relation-ship between each sensor of MMS is obtained by close-range photogrammetry. Second, the optimal solution for error correction is calculated by feature points in global coordinates jointly measured with International GNSS Service (IGS) stations. Then, the final transformation para-meters are solved by combining the initial values obtained originally, thereby realizing the rapid calibration of the MMS. Finally, it analyzed the RMSE of MMS point cloud after calibration, and the results demonstrate the feasibility of the calibration approach proposed by this method. Under the condition of a single measurement sensor accuracy is low, the plane and elevation absolute accuracy of the point cloud after calibration can reach 0.043 m and 0.072 m, respectively, and the relative accuracy is smaller than 0.02 m. It meets the precision require-ments of data acquisition for MMS. It is of great significance for promoting the development of MMS technology and the application of some novel techniques in the future, such as auton-omous driving, digital twin city, urban brain et al.

A method to interpret fracture aperture of rock slope using adaptive shape and unmanned aerial vehicle multi-angle nap-of-the-object photogrammetry

The aperture of natural rock fractures significantly affects the deformation and strength properties of rock masses,as well as the hydrodynamic properties of fractured rock masses.The conventional measurement methods are inadequate for collecting data on high-steep rock slopes in complex mountainous regions.This study establishes a high-resolution three-dimensional model of a rock slope using unmanned aerial vehicle(UAV)multi-angle nap-of-the-object photogrammetry to obtain edge feature points of fractures.Fracture opening morphology is characterized using coordinate projection and transformation.Fracture central axis is determined using vertical measuring lines,allowing for the interpretation of aperture of adaptive fracture shape.The feasibility and reliability of the new method are verified at a construction site of a railway in southeast Tibet,China.The study shows that the fracture aperture has a significant interval effect and size effect.The optimal sampling length for fractures is approximately 0.5e1 m,and the optimal aperture interpretation results can be achieved when the measuring line spacing is 1%of the sampling length.Tensile fractures in the study area generally have larger apertures than shear fractures,and their tendency to increase with slope height is also greater than that of shear fractures.The aperture of tensile fractures is generally positively correlated with their trace length,while the correlation between the aperture of shear fractures and their trace length appears to be weak.Fractures of different orientations exhibit certain differences in their distribution of aperture,but generally follow the forms of normal,log-normal,and gamma distributions.This study provides essential data support for rock and slope stability evaluation,which is of significant practical importance.

Three-dimensional finite element simulation and reconstruction of jointed rock models using CT scanning and photogrammetry

The geometry of joints has a significant influence on the mechanical properties of rocks.To simplify the curved joint shapes in rocks,the joint shape is usually treated as straight lines or planes in most laboratory experiments and numerical simulations.In this study,the computerized tomography (CT) scanning and photogrammetry were employed to obtain the internal and surface joint structures of a limestone sample,respectively.To describe the joint geometry,the edge detection algorithms and a three-dimensional (3D) matrix mapping method were applied to reconstruct CT-based and photogrammetry-based jointed rock models.For comparison tests,the numerical uniaxial compression tests were conducted on an intact rock sample and a sample with a joint simplified to a plane using the parallel computing method.The results indicate that the mechanical characteristics and failure process of jointed rocks are significantly affected by the geometry of joints.The presence of joints reduces the uniaxial compressive strength (UCS),elastic modulus,and released acoustic emission (AE) energy of rocks by 37%–67%,21%–24%,and 52%–90%,respectively.Compared to the simplified joint sample,the proposed photogrammetry-based numerical model makes the most of the limited geometry information of joints.The UCS,accumulative released AE energy,and elastic modulus of the photogrammetry-based sample were found to be very close to those of the CT-based sample.The UCS value of the simplified joint sample (i.e.38.5 MPa) is much lower than that of the CT-based sample (i.e.72.3 MPa).Additionally,the accumulative released AE energy observed in the simplified joint sample is 3.899 times lower than that observed in the CT-based sample.CT scanning provides a reliable means to visualize the joints in rocks,which can be used to verify the reliability of photogrammetry techniques.The application of the photogrammetry-based sample enables detailed analysis for estimating the mechanical properties of jointed rocks.

Digital close-range photogrammetric application to small-scale physical simulation experiment

In order to research the possibility of digital close-range photogrammetric surveying in small scale physical simulation experiment, physical model coinciding with engineering practice was constructed based on similar theory. The datum processing method and surveying precision of digital close-range photogrammetric were analyzed. And the function relationship between overburden subsidence factor qr and the ratio z/H of stratum horizon z and mining depth H was researched. The results show that surveying points position mean error along horizontal direction is ±0.131 mm and vertical direction is ±0.192 mm. Therefore, multi-taking station cross direction digital close-range photogrammetric can completely satisfy the precision need of physical simulation experiment. And the empirical formula can be utilized to represent evolution law of stratum subsidence factor.

A Comparative Experimental Study on the Blast-Resistant Performances of Single and Multi-Layered Thin Plates Under Close-Range Airblast Loading

The performance of multilayered thin steel plates subjected to close-range air blasts has been experimentally studied and compared with that of monolithic plates made of the same material and having equal mass. In present experiments, multilayered plates are in-contact four-layered thin steel plates and two types of deformation/failure modes were observed for them. Comparisons concerning deformation/failure modes, strain distributions and energy absorptions between the multilayered plate and its monolithic counterpart were conducted. It is found that the multilayered plate is much superior to its monolithic counterpart in the ability to deform against blast loading. Furthermore, under intense airblast loading, the multilayered plate can not only absorb much more energy but also effectively reduce the secondary destruction ability of structural fragments in comparison with its monolithic counterpart.

Architectural Model of a Dryland Gravel Braided River,based on 3D UAV Oblique Photogrammetric Data:A Case Study of West Dalongkou River in Eastern Xinjiang,China

Three-dimensional unmanned aerial vehicle(UAV)oblique photogrammetric data were used to infer mountainous gravel braided river lithofacies,lithofacies associations and architectural elements.Hierarchical architecture and lithofacies associations with detailed lithofacies characterizations were comprehensively described to document the architectural model,architectural element scale and gravel particle scale.(1)Nine lithofacies(i.e.,Gmm,Gcm,Gcc,Gci,Gcl,Ss,Sm,Fsm and Fl)were identified and classified as gravel,sand and fine matrix deposits.These are typical depositional features of a mountainous dryland gravel-braided river.(2)Three architectural elements were identified,including channel(CH),gravel bar(GB)and overbank(OB).CH can be further divided into flow channel and abandoned channel,while GB consists of Central Gravel bar(CGB)and Margin Gravel bar(MGB).(3)The gravel bar is the key architectural element of the gravel braided river,with its geological attributes.The dimensions of GBs and their particles are various,but exhibit good relationships with each other.The grain size of GB decreases downstream,but the dimensions of GB do not.The bank erosion affects the GB dimensions,whereas channel incision and water flow velocity influence the grain size of GB.The conclusions can be applied to the dryland gravel braided river studies in tectonically active areas.

基于无人机摄影测量的建筑表皮光伏设计与效益评估

在建筑表皮部署光伏(PV)是有前途的策略,可以使建筑生产可再生能源并实现社会的碳中和目标。当前缺乏用于光伏建筑集成设计和效益评估的建筑精细化实景建模方法,难以对光伏的产能和视觉效果进行详细分析,形成合理方案。以无人机倾斜摄影测量技术为基础,结合参数化分析和美学设计方法,探索出用于建筑表皮光伏设计和效益评估的整体性方法。对天津市一教育性建筑进行了案例研究,得到了优化的光伏组件部署方案和产能潜力评估结果。为今后更多建筑的屋顶、立面光伏设计提供理论依据和方法借鉴。

腰椎融合术中恢复椎间隙自然高度对手术疗效的影响

目的 探讨腰椎融合术中恢复椎间隙自然高度对手术疗效的影响。方法 测量100名健康志愿者腰椎各椎间隙高度和椎体高度,计算各椎间隙高度与椎体高度的比值及其95%置信区间(CI),并以此为正常值参考标准,将2019年6月-2021年6月接受腰椎后路融合术治疗的133例患者根据手术节段术后椎间隙高度与椎体高度比值是否在正常值95%CI内分为自然高度组(n=78)和非自然高度组(n=55)。记录并统计2组患者术中及术后并发症发生率,采用疼痛视觉模拟量表评分(VAS)和日本骨科学会(JOA)评分评估手术前后疼痛程度及神经功能。结果 末次随访时,自然高度组发生邻椎病3例,并发症发生率为3.8%;非自然高度组发生邻椎病5例,足下垂1例,并发症发生率为10.9%;2组并发症发生率差异有统计学意义(P <0.05)。2组术后各随访时间点腰腿痛VAS评分、JOA评分较术前明显改善,末次随访时自然高度组腰腿痛VAS评分、JOA评分改善率优于非自然高度组,差异均有统计学意义(P <0.05)。结论 腰椎融合术中椎间隙的撑开高度应参照椎体自身高度,控制手术节段的椎间隙高度与椎体高度比值在正常值95%CI内可有效改善神经功能并降低并发症发生率。

基于摄影测量的三轴土体剪切带演化规律

为实现土样局部变形的定向研究,同时优化土样的变形测量精度,将数字图像测量与三轴试验结合,在不对仪器做大型改造的条件下,运用摄影测量技术改良试验.以桂林地区红黏土为研究对象,试验全程对土样全表面进行受力变形监测,并还原土样的三维重构模型,以此研究其应力应变关系、局部应变特性、剪切带演化规律.研究结果表明:(1)土样表面的剪切带内外区域具有截然不同的变形特征,带外区域变形较为均匀且变形量趋于稳定,而带内区域变形不均匀且变形量不断加剧;(2)根据土样表面不同区域间的局部应变差异,确定了剪切带开始形成、停止扩张及完全贯穿的临界状态,提出了一种判别剪切带发展阶段的方法;(3)根据判别方法,将剪切带的演化过程拆分为压缩变形、表面扩张、延伸贯穿、相对滑移四个阶段,并分析了各个阶段不同的变形规律与破坏机理.经摄影测量技术改良的三轴试验,能够得到更准确的土体局部本构关系和变形特性,为探索土的应变局部化现象提供了一种精确且经济的研究方案.

无人机倾斜摄影测量在采空塌陷区生态综合治理中的应用

针对郭家湾煤矿51101工作面采空塌陷区生态综合治理问题,利用无人机搭载五镜头倾斜相机获取航摄影像,经过内业处理、三维建模获得实景三维模型。通过对像控点和三维模型精度分析,证明无人机倾斜摄影测量完全满足煤矿治理大比例尺地形图测图要求。依托实景三维模型和生成的高精度DLG数据成果,可帮助设计人员准确高效地提出相应采空塌陷区生态治理方式,大大提高了塌陷治理以及土地复垦工作的针对性和工作效率,为后期项目验收提供了准确可信的技术支撑和成果验证,最终有效解决了治理区地表变形和生态破坏问题。

基于无人机倾斜摄影测量三维建模的区域黄土滑坡识别及特征分析

【研究目的】黄土滑坡是黄土地区人居与城镇建设安全的重大隐患。滑坡识别是滑坡灾害及其他研究工作的基础,因此基于无人机倾斜摄影测量三维建模从不同维度、不同视角直观快速地识别黄土滑坡并进行特征参数提取,能够为黄土滑坡风险识别及风险管理精细化研究提供技术支撑。【研究方法】以宁夏回族自治区固原市彭阳县红河镇西南部的黑牛沟村为研究区,采用无人机倾斜摄影测量数据获取、三维建模、现场验证结合地统计学分析,开展了区域黄土滑坡识别及其特征参数提取和分析。【研究结果】基于三维实景模型确定并分析研究区沟谷沿线地貌凹陷区是否存在陡壁及其周界形态,结合色调、纹理和微地貌等标志实现了黄土滑坡识别,共圈定了23个滑坡,结合现场验证移除2个非滑坡点,最终确定了21个滑坡;滑坡密集分布在主沟和支沟沟口,多呈对滑的形式出现在沟谷两侧且具有群发性;大型及特大型滑坡占比达到57.14%,滑坡的滑动方向主要以西南(阳坡)、东南(半阳坡)为主,相对高差集中在80~120 m,滑坡体坡形多呈凹形坡,滑坡体坡度主要集中在20°~30°;滑坡体土地利用类型主要为植被,其次为裸地,也有一部分为农田,道路和河流占比极少。【结论】基于无人机倾斜摄影测量构建的三维实景模型可从多维度、多视角精确快速地识别区域黄土滑坡,并分析其相关特征参数,能够弥补当前二维平面遥感影像存在的不足;还能够为滑坡易发性、危险性、易损性及风险评估等相关研究提供数据支撑。

防止纹理扭曲的倾斜摄影模型轻量化算法

针对倾斜摄影模型网格简化后出现纹理扭曲的问题,基于二次误差度量算法(quadric error metrics,QEM),提出一种防止纹理扭曲的倾斜摄影模型轻量化算法。该算法依据模型中各顶点的拓扑连接关系对顶点进行分类,对不同类型的顶点制定相应的折叠策略,并引入顶点起伏度因子、纹理形变因子和顶点一环领域内三角形平均面积对QEM算法中的边折叠代价进行改进。实验结果表明,改进算法可以在高简化率下避免出现纹理扭曲现象,有效保持了模型的几何特征和纹理特征,并且相较于传统QEM算法,改进算法处理的模型最大误差、平均误差和均方差均分别至少降低了43.55%、52.50%和21.61%;在90%简化率的情况下,相较于带纹理模型的简化算法,改进算法处理的模型最大误差、平均误差和均方差分别降低了34.90%、10.61%和12.31%。

无人机倾斜摄影在土地调查中的应用

【目的】在我国土地调查发展过程中,常因技术手段存在缺陷,导致调查工作受到一定的影响。利用无人机倾斜摄影技术来建立实景三维模型,通过三维模型来完成相关调查工作,使土地调查工作更加高效、便捷。【方法】为探讨无人机倾斜摄影技术在土地调查工作中的应用优势,使用无人机搭载单目相机来采集影像,利用ContextCapture Center软件进行三维建模,并与实际调查结果进行对比,分析三维模型的优缺点。【结果】结果证明了该方法的可行性,建立的三维建模的土地边界清晰、建筑分明,可应用到土地调查工作中。【结论】无人机倾斜摄影技术可提高土地调查工作的完成效率,同时为我国未来的国土调查等工作提供支持。

大众众包技术在文物古迹数字化保护中的应用探讨

大数据分析表明,文物古迹数字化模型的在线传播和消费对文化遗产传承的影响显著,且趋势愈加明显。随着网络普及率的提高,数字化文化遗产在促进大众文化参与、丰富文化传承方式等方面发挥了积极作用。数字化模型的三维重建是一种非常普遍的文化遗产保护和存储方法,通过摄影测量技术,准确复制文化遗产对象的形态与色彩,进而实现其高质量的数字化重建。这种重建三维模型不需要设计师建模,考虑到摄影测量流程中的图像采集环节可以利用公众参与的力量,该文探讨了将大众众包技术应用于数字化文化遗产保护,建立众包共享平台的可行性,并提出了一种基于众包的图像采集方法,进一步阐明了大众众包技术在数字遗产领域的潜力。

无人机倾斜摄影测量在城市竣工测量中的应用

文章以无人机倾斜摄影测量技术作为切入点,分析该技术的测量原理、应用特点和系统组成结构,加强对无人机倾斜摄影测量技术的全面掌握,奠定技术应用推广基础。并重点阐述无人机倾斜摄影测量技术在城市竣工测量项目中的实践应用方法,以测量流程步骤、操作要点、注意事项作为阐述重点。旨在依托无人机倾斜摄影测量来打造新一代城市竣工测量技术体系,推动测量水准、作业效率和成果质量全面提升。

侗族鼓楼数字化保护研究

侗族鼓楼是国家级非物质文化遗产之一,其建筑技术和建筑文化的传承和发展非常重要。本文通过分析侗族鼓楼的传承现状,利用无人机贴近摄影测量技术对鼓楼建筑进行测绘,完成三维精细化模型建模,形成数字化技术储存鼓楼建筑的信息数据以及各类型的成果文档,为侗族鼓楼建筑的保护、修复和传承提供新的思路。

无人机倾斜摄影测量技术在林区植被恢复治理中的应用

林区植被破坏后,需要对破坏区域进行测量评估再实施恢复治理。林区由于树林的遮挡,存在通视困难。信号障碍等难题,使用传统的全站仪、GPS测量方法采集数据较为困难,本文提出,依靠无人机倾斜摄影测量模式获取空间数据,再通过三维建模,最后生成各类成果数据文件。项目实例应用证明本文的测量方法和模式有效,效果良好。