BIM-Based 3D Reconstruction Technology

BIM-Based 3D Re kink Technology optimisation Model of BIM- base multidimensional re expression applied science and engineering science standard of optic learningKeywords Three-dimensional re twirl, opthalmic perceptual model, engineering optimization, modeling, analysis.Abstract.Vision-establish re wind is placid there is a big limitation. Through its research-based approach introduces the primary optic troika-dimensional re whirl techniques, advantages and disadvantages of various manners were compared, it is desirable in this area heap have a more comprehensive grasp, to further clarify the worry of hereafter research. In mold to improve the cogency of the traffic pattern and construction of bridge circuit engineering, building data modeling (BIM) is introduced into the bridge project in the past. By analyzing the characteristics of bridge stick out and construction and the problems proposed bridge determination and construction BIM-based optimization solutions , including explorative shape optimization, optimization of construction design, construction put to work optimization, optimization of the construction schedule and construction management optimization, combined with applicative engineering project the applicability and effect analysis. Case screening shows, BIM duo Project is applicable, chiffonier provide effective victuals for the bridge design and construction, thereby reducing rework and improve qualification. The understand may be massive or complex bridge engineering BIM improve the efficiency and effectiveness of the design and construction of reference.IntroductionThe relevant information and selective information building information model is based on building projects as the basis for the model, building model were established by the real information of the digital information simulation building has, it has the visibility, coordination, simulated sex, optimality and showing of volt characteristics. The BIM t echnology in the field of bridge engineering construction is shortly in the early tips, preliminary exploration in the design, construction, and post-operation maintenance and liven up of the faultless(prenominal) life cycle of how to mathematical function BIM technology to improve design efficiency, improved design quality, strengthen the construction organization and post trading operations management, specific system and the application of BIM technology can bring benefits, hoping to BIM in bridge engineering to ascend ideas.In recent years, domestic construction projects in the field of non-BIM is none otherwise than the hottest technology in the construction industry has achieved good results after the application, the state began to vigorously promote the line, highway, water system conservancy and hydropower industry application of BIM technology in fields such as engineering, and bridge engineering in the construction field and a whacking proportion, especially hig h-speed railway, mountain railway, roads, bridges, often accounting for a larger significance in bridge engineering applications BIM technology on the entire major project, the paper result design, three stages of construction, operation and maintenance of the last mentioned part of the project life cycle are the hard-nosed application of research needs and the effect of BIM technology.In recent years, should the needs of scotch development, large, extra large bridge project more and more, such as China, Hangzhou Bay twain, the Hong Kong-Zhuhai-Macao Bridge, which bridge design and construction of a higher requirement. Bridge construction project not only involves complex geographical environment, and involves a name of complex projects, the most typical is the Steel Bridge. Currently, the design of large bridge projects usually rely on the traditional monotone drawings and graphs to contemplate the design by closing animate in conflict construction planning is largely dep endent on the experience of project managers to develop and implement, and is alike a flattened drawings to show. However, since the bridge project their own characteristics, its design complexity, component many rely solely on the traditional mat drawings thorny to detect in advance or ensnare conflicts existing in the design these design problems usually can be found in the construction phase, thus affecting the construction schedule and cost, will excessively affect construction safety. At the same time, in order to re elaborate the problem of engineering design and construction, we had to deploy more staff, which is in like manner a significant increase in management costs. Therefore, to ensure the feasibleness of the bridge may be constructed of engineering design and construction programs for in force(p) implementation of the bridge project is very big.Preliminary design stage is change integrity into two stages of design and post-design, including pre-design project approval, feasibility studies and scheme equality and other parts, three-d solid model of the bridge by victimisation parametric modeling tools can be easily established harmonize to the actual need to adjust the size, and the actual effect of the bridge into the real-time dynamic display, to achieve WYSIWYG, can intuitively design concept, design cause directly model the three-dimensional opticalization of the project as a carrier to deliver policy-makers, which greatly facilitate the adjustment of the design, be rewrite in accordance with amendments and rendering, and cost control by adding information to forbid abreast of changes after the investment increases and decreases, so that the bridge-bridge quickly determine preliminary program is very convenient and efficient. Figure 1 is a railway bridge stayed Bridge main bridge model, we need to establish a special bridge structure fit to the characteristics of the family library for complex bridge structure using three-dim ensional expression of BIM model than the traditional monotonic drawings clearer and easier to understand.The Proposed MethodologyThree-dimensional modeling techniques.The use of modeling software for three-dimensional modeling is commonly used mode, however modeling the need to hap a lot of manpower and material resources are often prohibitive, reconstructive memory effect is often unsatisfactory. Vision-based reconstructive memory technique to solve this problem and provides a new way of thinking.Three-dimensional visual sensation-based three-dimensional reconstruction technology, which uses electronic computing machine slew methods of three-dimensional model reconstruction of the quarry, is the use of a digital photographic camera as the image sensor, the integrated use of image cognitive processing, visual reckoning technologies such as non-contact dimensional measurement, sustaining object using a computer program information. The advantage is that the shape of the object is not restricted to retrace faster, can achieve automatic or semi-automatic modeling, three-dimensional reconstruction is an important direction of development, can be widely used, including autonomous mobile zombie navigation systems, remote sensing and aero musculus quadriceps femoris, industrial fields of automation systems, etc., the stinting benefits generated by this technology is very impressive.As an important branch of computer vision technology, vision-based three-dimensional reconstruction of Marr visual theoretical framework is based on the formation of a variety of theoretical approaches. For example, according to the number of cameras can be divided into monocular vision method, binocular vision method, three monocular vision or monocular vision method according to different principles, vision-based method can be divided into regions, feature-based visual method , model-based and rule-based visual methods according to the obtained data the way, can be divide d into active and passive visual method visual method.Figure.1 Three dimensional reconstruction technique tally to research at home and abroad in recent years, were selected based on visual presentation of three-dimensional reconstruction of research and practical application of several methods and more comparative analysis, pointed out the main challenges for the future and the future direction of development. Depending on the number of cameras to use, this article will be divided into three-dimensional reconstruction method based on the visual method of monocular vision, binocular vision trinocular vision method and three methods were introduced, counseling on the monocular vision method.Monocular vision method.Monocular vision method is the use of a camera for three-dimensional reconstruction method. Images used can be a single point of view of single or sextuple images can also be a multi-view seven-fold images. The former is mainly characterized by a two-dimensional image de pth information deduced, these features include two-dimensional shading, caryopsis, focus, contour, etc., it is also referred to as X shape recovery method. This simple winding structure class methods, the use of single or small number of several images can be reconstructed three-dimensional object model less than that normally required conditions more idealistic, practical application is not very satisfactory, the effects of reconstruction in general. The latter by twinned different images of the same feature points matching using these coordinates in space constraint obtaining information in order to achieve a three-dimensional reconstruction. This method can be implemented in the reconstruction process of camera calibration, to meet the needs of large-scale reconstruction of three-dimensional scene, and in the case of resource-rich image reconstruction is better the downside is that a greater list of computing, a long time to rebuild. The following describes several major mon ocular vision method.Shading method.Shading method, that the chic of the shape recovery method (SFS). This approach by analyzing image brightness information, using reflected light model, restore the normal to the come out of three-dimensional reconstruction information. Horn in 1970 first proposed the concept SFS methods, and gives a non-linear relationship between the two-dimensional image showing the brightness of distributively pixel in the corresponding three-dimensional point of law to the reflectance of light and the direction of Partial Differential Equations , the brightness of the equation.However, this method is a SFS under-constrained problem and needs to solve other constraints. Therefore, the traditional method of SFS also based on three assumptions. The main advantage of the brightness of the method is that it can recover from a single image in a more precise three-dimensional model can be apply in addition to mirror the object almost all types of objects. Howeve r, the brightness of the reconstruction of relying solely on mathematical calculations, results are poor, but because of the excitement conditions more stringent requirements, the need to know the precise position and preference of the light source and other information, so that the brightness of the method is difficult to apply in the case of an outdoor scene lighting and other complex three-dimensional reconstruction on.Photometric stereo.Although the shading method to support the reconstruction of three-dimensional model from a single image, but less information is available in a single image, the actual reconstruction of the general effect. So Woodham of SFS method is proposed to improve the photometric stereo.Photometric stereo by a plurality of non-collinear light source to obtain dual images of the object, and then a different image brightness simultaneous equations, settlement the coat normal direction of the object, and ultimately restore the shape of the object. Tech nically, the use of two light sources can be obtained method object to the information, but the use of multiple sources of data redundancy can be unflinching by the shadows and specular reflections caused by such factors can not solve the problem, better robustness, reconstruction effect It can be improved, so the genuine method basically using a plurality of (four to six) three-dimensional reconstruction of the light source.Photometric stereo advantages and brightness of the same law, the use of multiple images at the same time avoids the problems of ill shading method, and the use of multiple light sources also increased constraints, to improve the accuracy and robustness of the method it the disadvantage is difficult to apply a mirror surface object and three-dimensional reconstruction of outdoor scenes and objects. caryopsis law.Humans can surface texture by projection on the retina perceive three-dimensional shape of the object, so the visual image information gradient textu re can be used as information for Shape and depth cues. Based on this theory, the analysis can be repeated by surface texture social unit image size, the shape, the recovery of the normal object, the depth information to obtain three-dimensional geometric model of the object, i.e., texture pro cross-file method for recovery.Texture is the basic theory of law For a smooth surface and having a repeating texture units covering the object of which, when projected on the two-dimensional image, texture unit on which will be deformed, this deformation is divided into projection distortion (projective distortion ) and perspective shrinkage. Projection distortion so the farther away from the image plane texture unit looks smaller foreshortening distortion and image plane makes an angle greater texture unit looks shorter. Because these two variants can be measured from the image, so it can be analyzed after deformation texture units, reverse strike the surface normal and depth of informatio n, three-dimensional reconstruction. indite method. This method of contour images of objects finished a plurality of angles to give a three-dimensional model of the object. Profile method can be divided based on voxel cone prime three methods based on visual and shell.Figure.2 Visual perception modelConclusionReconstruction of 3D Vision technology is dormant in the exploratory stage, the practical application of the various methods is still nearly distance away from a variety of application needs to be urgently met. Therefore, in the future for a long period of time, we also need to do more intensive research in this field. This reflect shows that, BIM can provide effective support for the bridge design and construction. This study was expected to provide reference for increasing large, complex bridge design and construction efficiency and effectiveness, as well as assist in the promotion and application of BIM in the field of civil engineering. I deal that with the continuous promotion of theory and technology of BIM, BIM applications in civil engineering will become increasingly widespread, so as to improve their quality, efficiency and management level. Safety-critical structural bridge engineering, maintenance and repair of the late, operations management, file management can take advantage of powerful information technology BIM, visualization capabilities to achieve.