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.

Occurrence Regularity of Tobacco Cutworm Moth (Spodoptera Litura) in Low-Altitude Tobacco Cultivation Areas in Lincang

[ Objective ] The paper was to study the occurrence and damage regularity of tobacco cutworm moth （Spodoptera Litura Fabricius） in low-altitude area in Lincang city. [ Method] The adult sex attractant monitoring, field investigation of occurrence and damage, and observation of continuous generation development of natural populations were carried out in natural flue-cured tobacco fields. [ Result] In field growth period of flue-cured tobacco under low-altitude of 1 000 - 1300 m, tobacco cutworm moth occurred for 4 generations, the duration of each generation was about 33 d, and the main injurious generation was the third generation. [ Conclusion] The paper provided reference for comprehensive control of tobacco cutworm moth in the low altitude areas.

Analysis of Low-Altitude Inversion Characteristics of Coal-Fired Power Projects Based on Tethered Balloon Observation

Atmospheric inversion phenomenon directly affects the vertical movement of air, which causes the cooling heat of the cooling tower in the power plant to be blocked. Therefore, it is necessary to analyze the atmospheric inversion characteristics of the research project during the design of the air cooling system. Using the low-altitude observing system of the tethered balloon, the on-site observation of the temperature below 300 m in summer is carried out for a coal-fired power integration project in Yulin, Shaanxi, China. Observations were made at 10 fixed times per day, with a cumulative observation of 46 days and 247 effective detections. The data were quality-controlled, and then linearly interpolated. According to the requirements of the project designer, the temperature data of 20, 50, 100, 150, 200, 250, 300 m was used for low-temperature inversion analysis. The research shows that the grounding inversion and low-altitude inversion can be observed at the same time. In the time and space changes, the grounding inversion temperature and intensity are significantly higher than the low-altitude inversion. The maximum inversion of grounding inversion and low-altitude inversion is 2.3?C/hm, 1.0?C/hm. Grounding inversion temperature occurs every time, the frequency is the highest at 20 o’clock, the average intensity is maximum at 17 o’clock, and the average height, maximum intensity and maximum height are maximum at 7 o’clock. When the low-altitude inversion temperature is 18 o’clock, other times can occur, and the frequency is the highest at 15 o’clock, but the inversion layer is shallow, the bottom is high and the intensity is small. Grounding inversion and low-altitude inversion can occur in all levels, and as the height increases, the grounding inversion decreases and the low-temperature inversion increases. The design of the project air cooling tower needs to fully consider the impact caused by the inverse temperature below 300 m.

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。

基于Photogrammetry的地表变形监测技术研究

主要讨论了采用Photogrammetry技术监测地下施工过程中地表变形的主要方法和应用情况。地表变形过大往往会导致地表既有建筑物的破碎,所以量化监测其变形程度在地下施工中尤为重要。Photogrammetry技术是一种非接触式的变形监测技术,主要通过影像手段获取目标点的三维变形大小。该方法需要从空间多角度对目标点进行摄影测量,获取连续的三维影像信息,通过Photogrammetry软件进行现场目标点重现,进而获取三维可视目标点坐标值。本文通过现场的监测,获取了地表变形的数据,提出了监测的方法。

摄影测量局部场景稳健合并的并行式运动恢复结构方法

针对并行式运动恢复结构(SfM)在局部场景合并时稳健性差的问题,提出一种摄影测量局部场景稳健合并的并行式SfM方法。对整个场景的影像关联图进行分块及扩展处理,得到相互重叠的子区块,并利用一种改进的增量式SfM方法生成局部场景重建结果。在局部场景合并时,首先利用局部场景的重叠关系构建子区块关联图,并以子区块三元组为单元,进行粗差剔除;然后,利用子区块三元组的代数性质,优化得到更符合几何一致性的子区块间的相对变换;最后,从上述结果中计算得到更准确的局部场景到统一坐标系下的尺度、旋转、平移变换。试验采用无人机影像,结果表明本文方法在局部场景合并时有更好的稳健性,而且SfM结果的精确度也要优于其他并行式方法和COLMAP,在摄影测量和实景三维重建中有较大的应用潜力。

基于Photogrammetry的矿区地表沉降检测技术研究与应用

对Photogrammetry技术的主要原理进行了解析,并利用该技术从空间多角度对预先设置的20个目标点进行图像采集,获取连续的三维影像信息,通过PM软件进行采矿区目标点重现,获得了各个检测点的三维坐标大小,并对两种焦距下的图像处理结果进行了对比分析,对实际工程应用具有借鉴意义。

考虑夯锤姿态特性的夯沉量单目视觉测量方法研究

夯沉量是反映强夯地基加固质量的关键指标,人工测量方法不仅投入高、效率低下,且施工安全无法保障。为此,基于单目摄影测量提出一种强夯夯沉量非接触测量方法,实现了强夯夯沉量的高效测算。深入分析并科学定义了适用于单目视觉监测的夯沉量定义;基于夯锤标识的旋转不变性,提取表征夯锤姿态的特征点几何信息,结合视觉成像基本原理,构建了测算夯锤三维姿态的数值方程,求解得到夯锤特征点的三维坐标;在施工现场对所提方法进行工程实测,并通过多余观测对解算结果进行优化尝试。试验及工程应用结果表明,本方法具有精度高、速度快、稳健性强等特点,可有效应用于强夯施工质量监测关键指标参数夯沉量的自动解算,为当前强夯夯沉量自动化监测技术的进步提供了一个新的方向和手段。