3D Reconstruction Process Research Articles

Superalloys fracture process inference based on overlap analysis of 3D models

Superalloy materials exhibit susceptibility to fracture failures stemming from the influence of thermomechanical factors. To comprehensively understand the fracture mechanisms, material properties, root causes of failure, and the subsequent optimization of alloys, a detailed analysis of the internal fracture process and the morphological traits of the fracture surface is imperative. Traditional analysis of fracture surfaces solely relies on 2D images, thus lacking crucial 3D information. Although in situ experiments can capture the fracture process, their effectiveness is confined to the specimen’s surface, precluding insight into internal changes. Here we introduce an integrated framework encompassing the process of 3D reconstruction of fracture surfaces, aiming to enhance the visual information obtained with micron-level accuracy, visual intuitiveness and sense of depth. Additionally, this framework also facilitates the scrutiny and inference of internal fracture processes. These results demonstrate that under specific service conditions, material deformation fracture probably stems from a combination of surface cracking and internal cracking rather than exclusively one or the other. Overall, our description and analysis of internally initiated cracking due to defects within the specimens can be beneficial in guiding future alloy design and optimization efforts.

Use of scanning devices for object 3D reconstruction by photogrammetry and visualization in virtual reality

This article aims to compare two different scanning devices (360 camera and digital single lens reflex (DSLR) camera) and their properties in the three-dimensional (3D) reconstruction of the object by the photogrammetry method. The article first describes the various stages of the process of 3D modeling and reconstruction of the object. A point cloud generated to the 3D model of the object, including textures, is created in the following steps. The scanning devices are compared under the same conditions and time from capturing the image of a real object to its 3D reconstruction. The attributes of the scanned image of the recon-structed 3D model, which is a mandarin tree in a citrus greenhouse in a daylight environment, are also compared. Both created models are also compared visually. That visual comparison reveals the possibilities in the application of both scanning devices can be found in the process of 3D reconstruction of the object by photogrammetry. The results of this research can be applied in the field of 3D modeling of a real object using 3D models in virtual reality, 3D printing, 3D visualization, image analysis, and 3D online presentation.

BareSkinNet: De‐makeup and De‐lighting via 3D Face Reconstruction

AbstractWe propose BareSkinNet, a novel method that simultaneously removes makeup and lighting influences from the face image. Our method leverages a 3D morphable model and does not require a reference clean face image or a specified light condition. By combining the process of 3D face reconstruction, we can easily obtain 3D geometry and coarse 3D textures. Using this information, we can infer normalized 3D face texture maps (diffuse, normal, roughness, and specular) by an image‐translation network. Consequently, reconstructed 3D face textures without undesirable information will significantly benefit subsequent processes, such as re‐lighting or re‐makeup. In experiments, we show that BareSkinNet outperforms state‐of‐the‐art makeup removal methods. In addition, our method is remarkably helpful in removing makeup to generate consistent high‐fidelity texture maps, which makes it extendable to many realistic face generation applications. It can also automatically build graphic assets of face makeup images before and after with corresponding 3D data. This will assist artists in accelerating their work, such as 3D makeup avatar creation.

Three-Dimensional Model Extraction and Parameter Measurement of Cerebral Hemangioma Based on Mimics

In this paper, Mimics is using to reconstruct the 3D model of hemangioma from 2D cerebral angiography images. The process of 3D model reconstruction is formulated. The hemangioma model is extracted and the parameters of the hemangioma are measured, which provided a model basis for the structural design of the spring coil. The shape and structure of the coil are very important for the therapeutic effect. During the treatment, the coil is implanted into the hemangioma from outside the body through a catheter.

Synthetic Image Generation Using the Finite Element Method and Blender Graphics Program for Modeling of Vision-Based Measurement Systems.

Computer vision is a frequently used approach in static and dynamic measurements of various mechanical structures. Sometimes, however, conducting a large number of experiments is time-consuming and may require significant financial and human resources. On the contrary, the authors propose a simulation approach for performing experiments to synthetically generate vision data. Synthetic images of mechanical structures subjected to loads are generated in the following way. The finite element method is adopted to compute deformations of the studied structure, and next, the Blender graphics program is used to render images presenting that structure. As a result of the proposed approach, it is possible to obtain synthetic images that reliably reflect static and dynamic experiments. This paper presents the results of the application of the proposed approach in the analysis of a complex-shaped structure for which experimental validation was carried out. In addition, the second example of the process of 3D reconstruction of the examined structure (in a multicamera system) is provided. The results for the structure with damage (cantilever beam) are also presented. The obtained results allow concluding that the proposed approach reliably imitates the images captured during real experiments. In addition, the method can become a tool supporting the vision system configuration process before conducting final experimental research.

Addressing a Phanerozoic carbonate facies conundrum—sponges or clotted micrite? Evidence from Early Silurian reefs, South China Block

We describe Early Silurian carbonate reef facies containing amalgamated micritic masses, commonly layered, interpreted to have formed by bacterial processes creating clotted fabrics. However, some curved structures in these masses resemble published images of interpreted sponges, raising the question of their nature, relevant to many carbonate studies including reefs and mud mounds throughout the Phanerozoic. Many lithistid sponges are well-established but others are open to interpretation. For keratose sponges, Cambrian examples are known, but several interpreted cases in later rocks are not confirmed; one example in Devonian and Triassic rocks using 3D imaging did not lead to firm verification. Thus criteria to distinguish sponges and clotted micrites remain problematic. A careful approach to interpretation of such sponges is needed, they might instead be microbially-mediated clotted micritic masses. The difficult process of 3D reconstruction is likely needed to resolve this interesting issue of interpretation.

Comparative Study of 3D Reconstruction Methods from 2D Sequential Images in Sports

The process of 3D reconstruction is a basic problem in Computer Vision. However, recent researches have been successfully addressed by motion capture systems with body worn markers and multiple cameras. To recover 3Dreconstruction from fully-body human pose by single camera still remains a challenging problem. For instance, noisy background, variation in human appearance and self-occlusion were among these challenges. This thesis investigated methods of 3D reconstruction from monocular image sequences in dynamic activities such as sports. Six recent methods were selected based on they focused on recovery fully automated system for estimating 3D human pose for 2D joint location. These researches have been developed the algorithm that be able to solve ill-posed problem. Evaluation of the methods was divided in two sections. First, the theoretical and comparative study of each method was disclosed to identify the technique used, the problems that enquired and the results achieved in their approach. After that, the advantages and disadvantages of each method were listed. Also, several factors such as accuracy, self-occlusion and so on have been compared amongst these methods. In Second stage, based on the advantages found in the first stage of evaluation, three methods were chosen to be evaluated using specific data set. Initially, the codes of the three methods on PennAction dataset (tennis) were run and the performance of the methods in 3D reconstruction is showed. Then, the methods were tested on a mixed activities sequence from the CMU motion capture database. The novel of this study is evaluation of recent methods based on the accuracy of their performance on the specific dataset of tennis player. Also, we proposed a technique which combining specific advantages of each method to create a more efficient method for 3D reconstruction of 2D sequential images in the context of outdoor activities.

Application of three-dimensional reconstruction and printing as an elective course for undergraduate medical students: an exploratory trial.

Medical three-dimensional (3D) digital reconstruction and printing have become common tools in medicine, but few undergraduate medical students understand its whole process and teaching and clinical application. Therefore, we designed an elective course of 3D reconstruction and printing for students and studied its significance and practicability. Thirty undergraduate medical students in their second-year of study volunteered to participate in the course. The course started with three lessons on the theory of 3D digital reconstruction and printing in medicine. The students were then randomly divided into ten groups. Each group randomly selected its own original data set, which could contain a series of 2D images including sectional anatomical images, histological images, CT and MRI. Amira software was used to segment the structures of interest, to 3D reconstruct them and to smooth and simplify the models. These models were 3D printed and post-processed. Finally, the 3D digital and printed models were scored, and the students produced brief reports of their work and knowledge acquisition and filled out an anonymous questionnaire about their study perceptions. All the students finished this course. The average score of the 30 students was 83.1 ± 2.7. This course stimulated the students' learning interest and satisfied them. It was helpful for undergraduate students to understand anatomical structures and their spatial relationship more deeply. Students understood the whole process of 3D reconstruction and printing and its teaching and clinical applications through this course. It is significant and necessary to develop this course for undergraduate medical students.

基于非量测相片的三维模型重建

随着科技的发展，对视觉感受的要求提高，越来越多的三维影像产品进入生活，然而三维模型重建受到诸多限制，并未达到公众要求。近年来，用非量测相片进行三维重建成为三维模型重建的流行方式之一。本文主要介绍了使用非量测相片进行相机标定、特征点提取与匹配、极线约束与本征矩阵计算、三维重建、误差分析，最终完成三维模型重建的过程，并简要分析了此方法的应用前景。 With the development of science, the requirement of visual feeling is improved, an increasing number of three-dimensional image products enter life. Nevertheless, the three-dimensional model reconstruction is subject to many restrictions, and does not meet the public requirement. In recent years, three-dimensional reconstruction with non-measurement photos has become one of the popular ways of 3D model reconstruction. This paper mainly introduces the process of 3D model reconstruction, including the use of non-measurement photos for camera calibration, extraction and matching of feature points, line constraint and intrinsic matrix calculation, three-dimensional reconstruction, error analysis. Lastly, the paper briefly analyzes the prospect of this method.

Research on Digital Holographic 3D Reconstruction Software

Abstract Digital holography has a wide range of applications in displaying the surface morphology of three-dimensional objects. There have been many studies on the physical methods and implementation methods of digital holography. One of the main problems at present is to design a stable and fast reconfiguration software. This paper analyzes the basic principle of convolution based off-axis digital holographic reconstruction, and presents the process of 3D reconstruction of off-axis digital holography. The 3D reconstruction software of digital holography is designed and developed according to the basic principle and the process of reconstruction, and the parallel operation of 3D reconstruction is realized by OpenMP. Results show that the software can help researchers conveniently realize digital holographic three-dimensional reconstruction. The reconstructed parameters can be adjusted according to the requirements, and the spectra, intensity maps, phase maps and other information required in the reconstruction process can be obtained. The software meets the needs of digital three-dimensional reconstruction.

The reconstruction of drawn architecture

Among the many cases concerning the process of digital hypothetical 3D reconstruction a particular case is constituted by never realized projects and plans. They constitute projects designed and remained on paper that, albeit documented by technical drawings, they pose the typical problems that are common to all other cases. From 3D reconstructions of transformed architectures, to destroyed/lost buildings and part of towns.This case studies start from original old drawings which has to be implemented by different kind of documentary sources, able to provide - by means evidence, induction, deduction, analogy - information characterized by different level of uncertainty and related to different level of accuracy.All methods adopted in a digital hypothetical 3D reconstruction process show us that the goal of all researchers is to be able to make explicit, or at least intelligible, through a graphical system a synthetic/communicative level representative or the value of the reconstructive process that is behind a particular result.The result of a reconstructive process acts in the definition of three areas intimately related one each other which concur to define the digital consistency of the artifact object of study: Shape (geometry, size, spatial position); Appearance (surface features); Constitutive elements (physical form, stratification of building/manufacturing systems)The paper, within a general framework aimed to use 3D models as a means to document and communicate the shape and appearance of never built architecture, as well as to depict temporal correspondence and allow the traceability of uncertainty and accuracy that characterizes each reconstructed element.

3D Reconstruction and 3D Point Cloud Compression

3D reconstruction and 3D Point Cloud Compression of image sequences is an important application in computer graphics and image processing, especially in biomedical engineering. Based on the introduction of the basic principle of 3D reconstruction, this paper presents a simple and easy implementation process of 3D reconstruction, and focuses on the key technologies of point cloud acquisition, finally, the future research directions of 3D Point Cloud Compression is discussed.

Dense 3D facial reconstruction from a single depth image in unconstrained environment

With the increasing demands of applications in virtual reality such as 3D films, virtual human–machine interactions and virtual agents, the analysis of 3D human face is considered to be more and more important as a fundamental step in these tasks. Due to information provided by the additional dimension, 3D facial reconstruction enables aforementioned tasks to be achieved with higher accuracy than those based on 2D facial analysis. The denser the 3D facial model is, the more information it could provide. However, most existing dense 3D facial reconstruction methods require complicated processing and high system cost. To this end, this paper presents a novel method that simplifies the process of dense 3D facial reconstruction by employing only one frame of depth data obtained with an off-the-shelf RGB-D sensor. The proposed method is composed of two main stages: (a) the acquisition of the initial 3D facial point cloud with automatically 3D facial region cropping, and (b) the generating of the dense facial point cloud with RBF-based adaptive 3D point interpolation. Experiments reported in this paper demonstrate the competitive results with real-world data.

Developing a denoising filter for electron microscopy and tomography data in the cloud

The low radiation conditions and the predominantly phase-object image formation of cryo-electron microscopy (cryo-EM) result in extremely high noise levels and low contrast in the recorded micrographs. The process of single particle or tomographic 3D reconstruction does not completely eliminate this noise and is even capable of introducing new sources of noise during alignment or when correcting for instrument parameters. The recently developed Digital Paths Supervised Variance (DPSV) denoising filter uses local variance information to control regional noise in a robust and adaptive manner. The performance of the DPSV filter was evaluated in this review qualitatively and quantitatively using simulated and experimental data from cryo-EM and tomography in two and three dimensions. We also assessed the benefit of filtering experimental reconstructions for visualization purposes and for enhancing the accuracy of feature detection. The DPSV filter eliminates high-frequency noise artifacts (density gaps), which would normally preclude the accurate segmentation of tomography reconstructions or the detection of alpha-helices in single-particle reconstructions. This collaborative software development project was carried out entirely by virtual interactions among the authors using publicly available development and file sharing tools.

Recent Advances in the Application of Electron Tomography to Materials Chemistry

Nowadays, tomography plays a central role in pureand applied science, in medicine, and in many branches of engineering and technology. It entails reconstructing the three-dimensional (3D) structure of an object from a tilt series of two-dimensional (2D) images. Its origin goes back to 1917, when Radon showed mathematically how a series of 2D projection images could be converted to the 3D structural one. Tomographic X-ray and positron scanning for 3D medical imaging, with a resolution of ∼1 mm, is now ubiquitous in major hospitals. Electron tomography, a relatively new chemical tool, with a resolution of ∼1 nm, has been recently adopted by materials chemists as an invaluable aid for the 3D study of the morphologies, spatially-discriminating chemical compositions, and defect properties of nanostructured materials. In this Account, we review the advances that have been made in facilitating the recording of the required series of 2D electron microscopic images and the subsequent process of 3D reconstruction of specimens that are vulnerable, to a greater or lesser degree, to electron beam damage. We describe how high-fidelity 3D tomograms may be obtained from relatively few 2D images by incorporating prior structural knowledge into the reconstruction process. In particular, we highlight the vital role of compressed sensing, a recently developed procedure well-known to information theorists that exploits ideas of image compression and "sparsity" (that the important image information can be captured in a reduced data set). We also touch upon another promising approach, "discrete" tomography, which builds into the reconstruction process a prior assumption that the object can be described in discrete terms, such as the number of constituent materials and their expected densities. Other advances made recently that we outline, such as the availability of aberration-corrected electron microscopes, electron wavelength monochromators, and sophisticated specimen goniometers, have all contributed significantly to the further development of quantitative 3D studies of nanostructured materials, including nanoparticle-heterogeneous catalysts, fuel-cell components, and drug-delivery systems, as well as photovoltaic and plasmonic devices, and are likely to enhance our knowledge of many other facets of materials chemistry, such as organic-inorganic composites, solar-energy devices, bionanotechnology, biomineralization, and energy-storage systems composed of high-permittivity metal oxides.

WE-C-332-01: Cascaded Systems Analysis of the 3D NEQ of Cone-Beam CT: Investigation of Voxel Size in Relation to 3D Noise Aliasing

Purpose: A model is presented for calculating the 3D NEQ in cone‐beam CT(CBCT) to allow quantitative investigation of tradeoffs in image quality associated with acquisition and reconstruction techniques. The model is validated against experiment and employed to understand the effects of voxel size on NEQ, specifically analyzing the differences between voxel averaging (in the 3D image) and pixel binning (on the detector).Method and Materials: The 3D NEQ for CBCT was modeled using cascaded systems analysis. Models for the 2D MTF and NPS were extended to describe the process of 3D reconstruction to yield a 3D NEQ. To examine the specific question of voxel size, binning of detector pixels was described as an aperture / sampling process in the 2D projection domain, while slice averaging was described as an aperture / sampling process in the 3D domain. Analysis was performed across a range of conditions to examine tradeoffs in NEQ. Results: The model demonstrates excellent agreement with measurements across a broad range of conditions. The NEQ (particularly at high spatial frequency) depends strongly on the binning / sampling method due to NPS aliasing in both the projection and reconstruction domains. For larger slice thickness, binning of detector rows gives superior NEQ compared to slice averaging. Conversely, for increased axial voxel size, averaging voxels in the 3D domain is superior to 2D pixel binning. The complicated interplay between longitudinal and axial voxel size is rendered clear by the theoretical model. Conclusion: These results illustrate the value of 3D noise modeling in CBCT. The NEQ is shown to depend on noise aliasing effects that depend on the choice of binning / sampling of detector pixels and image voxels. This work helps to identify techniques that maximize NEQ by considering tradeoffs between spatial resolution, noise, and aliasing effects.

Dynamic concision for three-dimensional reconstruction of human organ built with virtual reality modelling language (VRML)

This research studies the process of 3D reconstruction and dynamic concision based on 2D medical digital images using virtual reality modelling language (VRML) and JavaScript language, with a focus on how to realize the dynamic concision of 3D medical model with script node and sensor node in VRML. The 3D reconstruction and concision of body internal organs can be built with such high quality that they are better than those obtained from the traditional methods. With the function of dynamic concision, the VRML browser can offer better windows for man-computer interaction in real-time environment than ever before. 3D reconstruction and dynamic concision with VRML can be used to meet the requirement for the medical observation of 3D reconstruction and have a promising prospect in the fields of medical imaging.

Automatic Classification of Biological Particles fromElectron-microscopy Images Using Conventional and Genetic-algorithm Optimized Learning Vector Quantization

Automatic classification of transmission electron-microscopy images is an important step in the complex task of determining the structure of biologial macromolecules. The process of 3D reconstruction from a set of such images implies their previous classification into homogeneous image classes. In general, different classes may represent either distinct biochemical specimens or specimens from different directions of an otherwise homogenous specimen. In this paper, a neural network classification algorithm has been applied to a real-data case in which it was known a priori the existence of two differentiated views of the same specimen. Using two labeled sets as a reference, the parameters and architecture of the classifier were optimized using a genetic algorithm. The global automatic process of training and optimization is implemented using the previously described g-lvq (genetic learning vector quantization) [10] algorithm, and compared to a non-optimized version of the algorithm, Kohonen‘s lvq (learning vector quantization) [7]. Using a part of the sample as training set, the results presented here show an efficient (approximately 90%) average classification rate of unknown samples in two classes. Finally, the implication of this kind of automatic classification of algorithms in the determination of three dimensional structure of biological particles is discused. This paper extends the results already presented in [11], and also improves them.