Improvement of Binocular Reconstruction Algorithm for Measuring 3D Pavement Texture Using a Single Laser Line Scanning Constraint

The dense and accurate measurement of 3D texture is helpful in evaluating the pavement function.To form dense mandatory constraints and improve matching accuracy,the traditional binocular reconstruction technology was improved threefold.First,a single moving laser line was introduced to carry out global scanning constraints on the target,which would well overcome the difficulty of installing and recognizing excessive laser lines.Second,four kinds of improved algorithms,namely,disparity replacement,superposition synthesis,subregion segmentation,and subregion segmentation centroid enhancement,were established based on different constraint mechanism.Last,the improved binocular reconstruction test device was developed to realize the dual functions of 3D texture measurement and precision self-evaluation.Results show that compared with traditional algorithms,the introduction of a single laser line scanning constraint is helpful in improving the measurement’s accuracy.Among various improved algorithms,the improvement effect of the subregion segmentation centroid enhancement method is the best.It has a good effect on both overall measurement and single pointmeasurement,which can be considered to be used in pavement function evaluation.

Design Method for Road Reconstruction and Expansion

This article analyzes the method for designing routes in road reconstruction and expansion projects,using an actual engineering project as an example.This includes an overview of a specific road reconstruction and expansion project,an analysis of the preexisting road,the basic principles of the design road project,and an analysis of the design methods and steps.This study aims to offer some guidance for road reconstruction and expansion design.

3D object reconstruction by point coordinates of 2D line drawings

It is a research subject in computer vision to 3D reconstruction of an object represented by a single 2D line drawing. Previous works on 3D reconstruction from 2D line drawings focus on objects with lines, plane, view, and so on. This paper mainly studies the 3D reconstruction from 2D line drawings. Besides, a new approach is proposed： it is that for the research of the point coordinates of 2D line drawings, so as to achieve the object reconstruction by the reconstruction of point coordinates. The reconstruction process includes： （1） the collection of point coordinates （X,Y） of 2D line drawings; （2） the derivation of mathematical formula about the reconstruction of the point of 2D line drawings, and calculating the corresponding point of the 3D coordinates; （3） the regeneration of 3D graphics with 3D points; （4） analyze error by the proportional of parallel of axonometric projection, in order to prove the accuracy of the method.

3D reconstruction of complex curved objects from line drawings

An active research topic in computer vision and graphics is developing algorithms that can reconstruct the 3D surface of curved objects from line drawings. There are a number of algorithms have been dedicated to solve this problem, but they can＇t solve this problem when the geometric structure of a curved object becomes complex. This paper proposes a novel approach to reconstructing a complex curved 3D object from single 2D line drawings. Our approach has three steps： （1） decomposing a complex line drawing into several simpler line drawings and transforming them into polyhedron; （2） reconstructing the 3D wireframe of curved object from these simpler line drawings and generating the curved faces; （3） combining the 3D objects into the complete objects. A number of examples are given to demonstrate the ability of our approach to successfully perform reconstruction of curved objects which are more complex than previous methods.

3D Reconstruction from 2D Line Drawings only with Visible Vertices and Edges

The human vision system can reconstruct a 3D object easily from single 2D line drawings even if the hidden lines of the object are invisible. Now, there are many methods have emulated this ability, but when the hidden lines of the object are invisible, these methods cannot reconstruct a complete 3D object. Therefore, we put forward a new algorithm to settle this hard problem. Our approach consists of two steps： （1） infer the invisible vertices and edges to complete the line drawing, （2） propose a vertex-based optimization method to reconstruct a 3D object.

Reconstructed annual glacier surface mass balance in theányêmaqên Mountains,Yellow River source,based on snow line altitude

Annual mass balance is an important factor that reflects glacier change and glacier meltwater resources.In this study,we analyzed the changes in glacier area,snow line altitude(SLA)and surface elevation in theányêmaqên Mountain region using multisource remote sensing data.Then,the annual mass balance of two glaciers was reconstructed by using SLA-mass-balance gradient method.The results showed that the glacier area in theányêmaqên Mountains decreased by 29.4 km2from 1985 to 2017.The average SLAs of the Halong Glacier and Yehelong Glacier were approximately 5290 m and 5188 m,respectively.The glacier mass balance for the two glaciers from 1990 to 2020 was-0.71 m w.e.a^(-1) and-0.63 m w.e.a^(-1),respectively.Our results indicate that SLA is an important indicator of glacier changes,and a long sequence of SLAs can more accurately reconstruct the glacier mass balance of the glacier.The mean annual glacial meltwater-fed streamflow is 1.45×10^(7)m^(3) and 1.12×10^(7)m^(3),respectively.Sensitivity analysis indicates that summer air temperature plays a leading role in regard to the influential climatic factors of glacial retreat in theányêmaqên Mountains.This highlights the potential of the methodology for application on reconstructing annual glacier surface mass balance at larger scales without direct measurements.

Glacier reconstruction of La Covacha Massif in Sierra de Gredos(central Spain) during the Last Glacial Maximum

A paleoglacier reconstruction during the Last Glacial Maximum(LGM) is presented for a high mountain area of La Covacha massif in Sierra de Gredos(Iberian Central System) in central Spain. The moraines that, according with the previous literature, had formed during the global LGM, were mapped through photo interpretation of digital aerial photographs and 3D images and detailed field surveys. The topography of the paleoglaciers was estimated using a simple steady-state model that assumed a perfectly plastic ice rheology, reconstructing the theoretical ice profiles and obtaining the ice thickness of the glaciers during the LGM. The reconstruction of the glaciers was carried out using automated and semi-automated physically-based models, obtaining more realistic results with semi-automated models. According to our study, the paleoglaciers in the study area covered an area of 34.79 km^2 during the global LGM, with a maximum ice thickness of 366 meters in La Vega gorge, a total volume of 34.25 × 108 m^3 and a mean paleoELA of 1932 meters. Most of the ice(~82%) was in paleoglaciers facing north, and the rest was in paleoglaciers with other orientations. This emphasizes the importance of orientation in relation to glacier dynamics and ice accumulation. The results obtained in the calculation of paleoELAs during the global LGM in Gredos are average compared to the Iberian mountains of the Northwest where the values were much lower, and with respect to those of the Southwest, much higher. This demonstrates the importance of the exposure of Mediterranean mountains to the humidity sources coming from the NW during the global LGM, as is the case at present.

Total Nasal Tip Defect:Bilateral Lateral Nasal Artery Flaps for Lining Reconstruction

Background In full-thickness nasal defects,the internal lining is perhaps the most challenging aspect of the three layers to rebuild.Nasal damage is usually more concentrated on the tip,soft triangles,alar wings,and columella,but the lateral nasal arteries are often left intact and the damage to the dorsal sidewalls are normally superficial.Methods Twelve patients who required total nasal reconstruction received a forehead flap placement as external coverage and autologous rib cartilage as structural support.Residual normal/superficial scar tissue flaps on the dorsal sidewalls with lateral nasal artery pedicles were mobilized and designed for internal lining repair without creating secondary donor site damage.The flaps were then turned 180°downward and placed between the alar medial angles and the fornix.Results No total lining flap necrosis occurred in all the patients.Partial necrosis occurred on the distal edge owing to overpressure of the nostril splint to the flaps;however,the wounds eventually healed,and the nasal structural integrity was preserved.The patients were satisfied with the aesthetic results and had no complaints of airway stenosis.Conclusions Lateral nasal artery pedicle dorsal sidewall skin flaps are appropriately thick,providing enough nostril circumferential support to improve airway stenosis.It allows sufficient blood supply and creates no extra donor site damage.Blood vessels and skin flaps are often undamaged,thereby allowing maximum application in total nasal reconstruction.

Paleo-glacial reconstruction of the Thajwas glacier in the Kashmir Himalaya using 10Be cosmogenic radionuclide dating

Quantitative glacial chronologies of past glaciations are sparse in the Himalaya, and mostly absent in the Kashmir Himalaya. We used cosmogenicBe exposure dating, and geomorphological mapping to reconstruct glacial advances of the Thajwas Glacier(TG) in the Great Himalayan Range of the Kashmir Himalaya. FromBe exposure dating of ten moraine boulders, four glacial stages with ages ~20.77 ±2.28 ka, ~11.46 ± 1.69 ka, ~9.12 ± 1.39 ka and ~4.19 ± 0.78 ka, were identified. The reconstructed cosmogenic radionuclide ages confirmed the global Last Glacial Maximum(g LGM), Younger Dryas, Early Holocene, and Neoglaciation episodes. As per area and volume change analyses, the TG has lost 51.1 km~2 of its area and a volume of 2.64 km~3 during the last 20.77 ± 2.28 ka. Overall, the results suggested that the TG has lost 64% of area and 73% of volume from the Last glacial maximum to Neoglaciation and about 85.74% and 87.67% of area and volume, respectively, from Neoglaciation to the present day. The equilibrium line altitude of the TG fluctuated from 4238 m a.s.l present to3365 m a.s.l during the g LGM(20.77 ± 2.28 ka). The significant cooling induced by a drop in mean ambient temperature resulted in a positive mass balance of the TG during the g LGM. Subsequently the melting accelerated due to the continuing rise of the global ambient temperature. Paleo-glacial history reconstruction of the Kashmir Himalaya, with its specific geomorphic and climatic setting, would help close the information gap about the chronology of past regional glacial episodes.

Projects Lists Relating to Post-disaster Reconstruction

Aba Prefecture Company Name:Sichuan Xintong New Materials Co.Ltd. Address:Shuimo,Wenchuan Nature of Business:Private Project Name:Processing and Sale of Tourism Products Details:Producing and processing of Natural crystal products,man-made gem and other

既有线改建市域铁路客流量低迷原因及对策

[目的]针对目前由既有线改建而成的市域铁路普遍存在的客流量低迷问题,有必要系统分析其原因并提出相应对策,以提升运营效益,便利市郊旅客出行。[方法]通过对长江三角洲地区3条既有线改建的市域铁路进行调研,特别是对上海金山铁路全年客流量进行多维度分析,从时间和空间两个维度总结客流分布特点。基于定量分析,归纳市域铁路客流构成及时空波动特征;结合线路工作人员长期观察,定性分析客流需求及市域铁路对沿线居民的影响。综合定量与定性分析结果,针对3条市域铁路的具体客流现状,重点分析影响市域铁路客流量的因素,并提出提高市域铁路客流量的措施。[结果及结论]我国市域铁路客流量低迷的主要原因包括:市域客流自身特征因素,线路条件的局限性,列车开行方案的局限性,出行便捷性不足,以及市场竞争力不强等。提高市域铁路客流量的措施包括:完善线网规划与建设,提升线路通过能力,优化列车开行方案,完善线路间的衔接换乘,坚持公益性票价政策,推进公交引导发展综合改造等。

隧道衬砌结构不确定性分析与测点布置研究

在隧道工程中,确保衬砌结构安全至关重要,其中内力分析和安全评估是关键。通过数值模拟和现场监控量测手段分析结构内力,计算关键部位的安全系数。鉴于建模和测量误差的存在,引入概率模型量化安全系数估计的不确定性,并对轴力和弯矩的重构误差进行归一化处理,全面评价测点适宜性。以安徽境内某隧道为例,综合分析围岩压力分担比、水平围岩压力系数和测量噪声等因素对安全系数估计的影响,估计所得安全系数总体符合正态分布趋势,拱顶中部和拱肩位置处的安全系数波动较大。以减少估计不确定性和内力信息重构偏差为目标,结合现场实际工作条件安排测点位置。长期监测数据表明,二次衬砌结构内力在浇筑初期受多种因素影响波动明显,100 d后趋于稳定,结构安全储备充足。研究结果可为隧道衬砌结构安全系数统计分析和测点布置提供参考。

A Precise Information Extraction Algorithm for Lane Lines

Lane line detection is a fundamental step in applications like autonomous driving and intelligent traffic monitoring. Emerging applications today have higher requirements for accurate lane detection. In this paper, we present a precise information extraction algorithm for lane lines. Specifically, with Gaussian Mixture Model(GMM), we solved the issue of lane line occlusion in multi-lane scenes. Then, Progressive Probabilistic Hough Transform(PPHT) was used for line segments detection. After K-Means clustering for line segments classification, we solved the problem of extracting precise information that includes left and right edges as well as endpoints of each lane line based on geometric characteristics. Finally, we fitted these solid and dashed lane lines respectively. Experimental results indicate that the proposed method performs better than the other methods in both single-lane and multi-lane scenarios.

Latest advances of X-ray imaging and biomedical applications beamline at SSRF

On May 6, 2009, the X-ray imaging and biomedical application beamline(BL13W1) at Shanghai Synchrotron Radiation Facility(SSRF) officially opened to users, with 8–72.5 ke V X-rays. The experimental station is equipped with four sets of X-ray CCD detectors of different pixel size(0.19–24 μm) for on-line phase-contrast imaging and micro-CT imaging with 0.8 μm spatial resolution and 1 ms temporal resolution. An in vivo microCT experiment for a living insect was realized in 4 s. An X-ray fluorescence detector is equipped for X-ray fluorescence mapping imaging and X-ray fluorescence micro-CT imaging with 50 μm spatial resolution. In order to meet different requirements from the users, several experimental methods, such as X-ray spiral micro-CT, Xray local micro-CT, X-ray fast micro-CT, X-ray grating-based differential micro-CT, X-ray fluorescence microCT and X-ray quantitative micro-CT have been developed, and nearly 60 papers related to those developments for this beamline have been published. Moreover, the beamline has realized the remote fast CT reconstruction,providing a great convenience for the users to process experimental data at their offices. As of August 2014,the beamline has offered the user beamtime of(23 145 h), from which 232 user papers have been published,including 151 SCI papers and 55 papers with SCI impact factor > 3. The quantity and quality of the user paper outcome keep a steady increase. Some typical user experimental results are introduced.

城市实景模型结构化线面特征重构方法

为了改善城市实景模型边缘模糊,提出了一种曲率引导的结构化线面特征重构方法。根据曲率特征将网格分割为平面、可展凹、可展凸以及不可展曲面4类,在平面分割结果内提取平面,在可展凹和可展凸分割结果内提取直线,对过度弯曲的不可展区域进行保留,最终形成包含几何特征的复合网格模型。结果表明,结合曲率信息预先设置几何特征的潜在范围,使得结构化线面特征更可靠,同时保证城市实景中复杂的树结构不被错误地提取为平面。

线卷积网络在二维线检测和三维线框重建中的应用

本文提出了一个线卷积网络,可以从图像中检测线段.通过预测每条线段的中心位置、长度和角度,该网络能够以端到端的方式检测线段.此外,根据线中心检测的特点,本文设计了一维旋转卷积模块,并通过分析,证明其满足等变性质.在实现上,本文采用改进的数据增强和非极大值抑制方法,有效的提高了线检测的性能.通过大量消融实验以及对比实验,本文提出的线卷积网络相比于当前最优算法HAWP,在精度上高出3个百分点,达到了当前最优.最后,将该方法应用于单张图三维线框重建任务,从可视化结果上看,明显优于之前的方法.

基于智能制造专业群中“传感器及检测技术”课程教学改革研究

传感器的广泛应用和不断创新,以及技术推广的持续发展,使得传感器市场前景广阔,具有很大的发展潜力。传感器作为现代工业自动化的重要组成部分,决定了该类课程在高职自动化专业中的地位。在各高职专业未整合发展时,专业教师依据“传感器及检测技术”课程中所需的传感器知识进行教育教学实践。但是,在当前工业自动化的大环境中,各高职院校都重视专业群的建设,该类课程作为专业群的核心课程必须进行重构,在教学内容、教学策略和教学评价等方面进行改革,以便适应专业群各专业课程的统筹教学。

上海轨道交通既有线运能提升研究

[目的]通过总结上海城市轨道交通既有线运能提升改造项目的实施经验,为其提出有效的运能提升方法及具体案例。[方法]深入分析上海轨道交通既有线运能不足的主要原因及其影响因素;基于这些分析,提出运能提升的技术路线及5大核心策略;详细介绍了上海轨道交通9号线实现1 min 50 s最小行车间隔、3号线与4号线增能改造、5号线从4节编组扩编至6节编组、6号线增能改造及增设复线等成功案例。[结果及结论]影响线路运能的主要因素包括车辆基地规模、区间通过能力、出入场能力,以及供电能力等。针对这些因素,确定了运能提升的技术路线,即从客流预测及客流特征分析入手,进行设施设备能力评估,设计行车交路方案,最终形成科学的改造方案。同时,提出了5大策略:运营管理优化、既有系统能力挖潜及改造、信号系统升级或土建局部改造、系统规模性改造及线网整体优化。

基于主线不停运的城轨支线独立运营改造方案

研究目的:针对大型铁路枢纽接入已运营轨道交通线路引起的既有线改造问题,为满足铁路枢纽与轨道交通连接线(支线)施工期间主线正常运营不受影响,对改造涉及的运营组织与接轨方案进行系统研究,并对土建、轨道、接触网、环网与动照、信号、综合监控与通信系统等的改造及影响进行深入研究,在统筹考虑实施难度、投资与工期的基础上,提出实施风险最小、技术最合理的改造方案。研究结论:(1)既有高架车站与区间改造影响范围较小且相对可控,可以实现主线正常运营情况下新建独立运营支线工程;(2)为最大程度保障主线运营不受影响,在现有技术水平条件下,应尽量避免在运营天窗期进行各类信号光电缆的割接;(3)支线独立运营方案,应尽量采取措施将新建支线与主线相连、轨道相通,以利于车辆检修与维保,并增加运营的灵活性;(4)桥梁浇筑与平移施工临近既有线,实施阶段应进一步完善工艺衔接与交叉施工统筹,增加既有线安全保障;(5)本研究结论可为类似工程提供参考。

CT重建层厚和定位光精度自动分析方法研究

目的:提出一种用于测量CT重建层厚和定位光精度的自动分析方法。方法:以CT扫描Catphan500型检测模体的CTP401模块重建后的图像为研究对象,采用斜线法和交叉斜线法,借助MATLAB软件,利用OTSU算法实现对CT重建层厚和定位光精度的自动分析,得出CT重建层厚和定位光精度的测量结果,并对2种方法测量结果的准确性进行对比分析。结果:采用斜线法根据3点、6点、9点和12点处金属丝的长度计算所得的CT重建层厚分别为10.69、10.69、10.49和10.69 mm,根据3点、6点、9点和12点处金属丝影像中心到模块中心的距离计算所得的定位光精度分别为-0.092、0.079、0.060和-0.014 mm;采用交叉斜线法根据3点和9点处金属丝的长度计算所得的CT重建层厚为10.70 mm,根据6点和12点处金属丝的长度计算所得的CT重建层厚为10.80 mm,根据3点、6点、9点和12点处金属丝影像中心到模块中心的距离计算所得的定位光精度分别为-0.092、0.080、0.061和-0.014 mm。采用交叉斜线法计算得到的CT重建层厚更接近真实值,采用斜线法和交叉斜线法测得的定位光精度在相应点位处的数值基本相同。结论:提出的自动分析方法可客观、准确地测量CT重建层厚和定位光精度。