Download or read book 3D Reconstruction of Deformable Surface Based on Binocular Vision written by Bo Yang and published by . This book was released on 2020-11-30 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The 3D reconstruction of deformable surfaces is a classical problem in the field of computer vision, which has many important applications in virtual reality, surgical navigation, and training. For example, accurate 3D reconstruction for intracavitary soft-tissue scenes based on a stereo-endoscope can effectively promote surgeons and surgical robots' perception in a Minimally Invasive Surgery (MIS), and thus improve the precision and safety of surgical operations. However, the dynamic deformable soft-tissues bring great challenges for accurate reconstruction. This book provides an in-depth discussion about the binocular reconstruction techniques for dynamic deformable surfaces such as beating heart surfaces. The camera models and calibration methods used for stereo vision are introduced first. The classical stereo matching methods are then presented. The deformable-model-based reconstruction methods are discussed emphatically, from the common-used deformable models, such as the triangular affine transformation, the B-spline model, and the Thin Plate Spline (TPS), to some improved models proposed recently, such as the Quasi-Spherical Triangle (QST) model, the overlapping TPS model, and the Triangular Radial Cubic Spline (TRCS) model. This book includes Reconstruction techniques based on machine learning, statistical deformable modeling using principal component analysis, and Deep-learning methods for deformable surface reconstruction with selected experimental results.

Download or read book Deformable Surface 3D Reconstruction from Monocular Images written by Amit Roy-Chowdhury and published by Springer Nature. This book was released on 2022-05-31 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: Being able to recover the shape of 3D deformable surfaces from a single video stream would make it possible to field reconstruction systems that run on widely available hardware without requiring specialized devices. However, because many different 3D shapes can have virtually the same projection, such monocular shape recovery is inherently ambiguous. In this survey, we will review the two main classes of techniques that have proved most effective so far: The template-based methods that rely on establishing correspondences with a reference image in which the shape is already known, and non-rigid structure-from-motion techniques that exploit points tracked across the sequences to reconstruct a completely unknown shape. In both cases, we will formalize the approach, discuss its inherent ambiguities, and present the practical solutions that have been proposed to resolve them. To conclude, we will suggest directions for future research. Table of Contents: Introduction / Early Approaches to Non-Rigid Reconstruction / Formalizing Template-Based Reconstruction / Performing Template-Based Reconstruction / Formalizing Non-Rigid Structure from Motion / Performing Non-Rigid Structure from Motion / Future Directions

Download or read book Deformable Surface 3D Reconstruction from Monocular Images written by Matthieu Salzmann and published by Morgan & Claypool Publishers. This book was released on 2010-03-03 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: Being able to recover the shape of 3D deformable surfaces from a single video stream would make it possible to field reconstruction systems that run on widely available hardware without requiring specialized devices. However, because many different 3D shapes can have virtually the same projection, such monocular shape recovery is inherently ambiguous. In this survey, we will review the two main classes of techniques that have proved most effective so far: The template-based methods that rely on establishing correspondences with a reference image in which the shape is already known, and non-rigid structure-from-motion techniques that exploit points tracked across the sequences to reconstruct a completely unknown shape. In both cases, we will formalize the approach, discuss its inherent ambiguities, and present the practical solutions that have been proposed to resolve them. To conclude, we will suggest directions for future research. Table of Contents: Introduction / Early Approaches to Non-Rigid Reconstruction / Formalizing Template-Based Reconstruction / Performing Template-Based Reconstruction / Formalizing Non-Rigid Structure from Motion / Performing Non-Rigid Structure from Motion / Future Directions

Download or read book Contributions to Monocular Deformable 3D Reconstruction written by Mathias Gallardo and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Monocular deformable 3D reconstruction is the general problem of recovering the 3D shape of a deformable object from monocular 2D images. Several scenarios have emerged: the Shape-from-Template (SfT) and the Non-Rigid Structure-from-Motion (NRSfM) are two approaches intensively studied for their practicability. The former uses a single image depicting the deforming object and a template (a textured 3D shape of this object in a reference pose). The latter does not use a template, but uses several images and recovers the 3D shape in each image. Both approaches rely on the motion of correspondences between the images and deformation priors, which restrict their use to well-textured surfaces which deform smoothly. This thesis advances the state-of-the-art in SfT and NRSfM in two main directions. The first direction is to study SfT for the case of 1D templates (i.e. curved, thin structures such as ropes and cables). The second direction is to develop algorithms in SfT and NRSfM that exploit multiple visual cues and can solve complex, real-world cases which were previously unsolved. We focus on isometric deformations and reconstruct the outer part of the object. The technical and scientific contributions of this thesis are divided into four parts. The first part of this thesis studies the case of a curvilinear template embedded in 2D or 3D space, referred to Curve SfT. We propose a thorough theoretical analysis and practical solutions for Curve SfT. Despite its apparent simplicity, Curve SfT appears to be a complex problem: it cannot be solved locally using exact non-holonomic partial differential equation and is only solvable up to a finite number of ambiguous solutions. A major technical contribution is a computational solution based on our theory, which generates all the ambiguous solutions.The second part of this thesis deals with a limitation of SfT methods: reconstructing creases. This is due to the sparsity of the motion constraint and regularization. We propose two contributions which rely on a non-convex energy minimization framework. First, we complement the motion constraint with a robust boundary contour constraint. Second, we implicitly model creases with a dense mesh-based surface representation and an associated robust smoothing constraint, which deactivates curvature smoothing automatically where needed, without knowing a priori the crease location. The third part of this thesis is dedicated to another limitation of SfT: reconstructing poorly-textured surfaces. This is due to correspondences which cannot be obtained so easily on poorly-textured surfaces (either sparse or dense). As shading reveals details on poorly-textured surfaces, we propose to combine shading and SfT. We have two contributions. The first is a cascaded initialization which estimates sequentially the surface's deformation, the scene illumination, the camera response and then the surface albedos from deformed monocular images. The second is to integrate shading to our previous energy minimization framework for simultaneously refining deformation and photometric parameters.The last part of this thesis relaxes the knowledge of the template and addresses two limitations of NRSfM: reconstructing poorly-textured surfaces with creases. Our major contribution is an extension of the second framework to recover jointly the 3D shapes of all input images and the surface albedos without any template.

Download or read book Image based Deformable 3D Reconstruction Using Differential Geometry and Cartan s Connections written by Shaifali Parashar and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reconstructing the 3D shape of objects from multiple images is an important goal in computer vision and has been extensively studied for both rigid and non-rigid (or deformable) objects. Structure-from-Motion (SfM) is an algorithm that performs the 3D reconstruction of rigid objects using the inter-image visual motion from multiple images obtained from a moving camera. SfM is a very accurate and stable solution. Deformable 3D reconstruction, however, has been widely studied for monocular images (obtained from a single camera) and still remains an open research problem. The current methods exploit visual cues such as the inter-image visual motion and shading in order to formalise a reconstruction algorithm. This thesis focuses on the use of the inter-image visual motion for solving this problem. Two types of scenarios exist in the literature: 1) Non-Rigid Structure-from-Motion (NRSfM) and 2) Shape-from-Template (SfT). The goal of NRSfM is to reconstruct multiple shapes of a deformable object as viewed in multiple images while SfT (also referred to as template-based reconstruction) uses a single image of a deformed object and its 3D template (a textured 3D shape of the object in one configuration) to recover the deformed shape of the object. We propose an NRSfM method to reconstruct the deformable surfaces undergoing isometric deformations (the objects do not stretch or shrink under an isometric deformation) using Riemannian geometry. This allows NRSfM to be expressed in terms of Partial Differential Equations (PDE) and to be solved algebraically. We show that the problem has linear complexity and the reconstruction algorithm has a very low computational cost compared to existing NRSfM methods. This work motivated us to use differential geometry and Cartan's theory of connections to model NRSfM, which led to the possibility of extending the solution to deformations other than isometry. In fact, this led to a unified theoretical framework for modelling and solving both NRSfM and SfT for various types of deformations. In addition, it also makes it possible to have a solution to SfT which does not require an explicit modelling of deformation. An important point is that most of the NRSfM and SfT methods reconstruct the thin-shell surface of the object. The reconstruction of the entire volume (the thin-shell surface and the interior) has not been explored yet. We propose the first SfT method that reconstructs the entire volume of a deformable object.

Download or read book View Synthesis written by Fouad Sabry and published by One Billion Knowledgeable. This book was released on 2024-05-05 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: What is View Synthesis In the field of computer graphics, view synthesis, also known as novel view synthesis, is a task that involves the generation of images of a particular topic or scene from a particular point of view. This method is utilized in situations where the only information that is available is photographs taken from various points of view. How you will benefit (I) Insights, and validations about the following topics: Chapter 1: View synthesis Chapter 2: Image registration Chapter 3: Image-based modeling and rendering Chapter 4: Active vision Chapter 5: 3D reconstruction Chapter 6: Omnidirectional (360-degree) camera Chapter 7: 2D to 3D conversion Chapter 8: DeepDream Chapter 9: Visual Sensor Network Chapter 10: Video super-resolution (II) Answering the public top questions about view synthesis. (III) Real world examples for the usage of view synthesis in many fields. Who this book is for Professionals, undergraduate and graduate students, enthusiasts, hobbyists, and those who want to go beyond basic knowledge or information for any kind of View Synthesis.

Download or read book 3 D Surface Geometry and Reconstruction Developing Concepts and Applications written by Chandra Pati, Umesh and published by IGI Global. This book was released on 2012-02-29 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This book provides developers and scholars with an extensive collection of research articles in the expanding field of 3D reconstruction, investigating the concepts, methodologies, applications and recent developments in the field of 3D reconstruction"--

Download or read book Robust Methods for Dense Monocular Non Rigid 3D Reconstruction and Alignment of Point Clouds written by Vladislav Golyanik and published by Springer Nature. This book was released on 2020-06-04 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vladislav Golyanik proposes several new methods for dense non-rigid structure from motion (NRSfM) as well as alignment of point clouds. The introduced methods improve the state of the art in various aspects, i.e. in the ability to handle inaccurate point tracks and 3D data with contaminations. NRSfM with shape priors obtained on-the-fly from several unoccluded frames of the sequence and the new gravitational class of methods for point set alignment represent the primary contributions of this book. About the Author: Vladislav Golyanik is currently a postdoctoral researcher at the Max Planck Institute for Informatics in Saarbrücken, Germany. The current focus of his research lies on 3D reconstruction and analysis of general deformable scenes, 3D reconstruction of human body and matching problems on point sets and graphs. He is interested in machine learning (both supervised and unsupervised), physics-based methods as well as new hardware and sensors for computer vision and graphics (e.g., quantum computers and event cameras).

Download or read book 3D Reconstruction of Deformable Surfaces Using Isometry written by Ajad Chhatkuli and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Variation Based Dense 3D Reconstruction written by Sven Painer and published by Springer. This book was released on 2016-03-08 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: In his master thesis, Sven Painer develops, implements, and evaluates a method to reconstruct the liver surface from monocular mini-laparoscopic sequences. The principal focus of his research is to create a basis for helping clinicians to write reports with quantitative descriptions of the liver surface. A Structure from Motion approach is performed to do a sparse reconstruction of the liver surface and subsequently this information is used in a variation based dense 3D reconstruction. The algorithms are formulated in a causal way, enabling the implementation to be run in real-time on an adequate hardware platform. The results show a significant performance increase and pave the way to give clinicians a feedback during video capturing to improve the quality of the reconstruction in the near future.

Download or read book Multi camera Reconstruction and Rendering for Free viewpoint Video written by Bastian Goldlücke and published by Cuvillier Verlag. This book was released on 2005 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Improving the Accuracy of 3 D Reconstruction in Robotic Vision Applications written by Yuanzheng Gong and published by . This book was released on 2016 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three-dimensional (3D) surface reconstruction is a process for retrieving the 3D shape and appearance of real objects or scenes. The generated 3D point clouds can be used in many fields, including entertainment, measurement, design, reverse engineering, homeland security and {\it etc}. Over the past decades, 3D reconstruction has been widely used in clinical diagnosis and surgical treatment of diseases, such as X-ray, ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI). However, all of these technologies are radiography-based volumetric 3D reconstruction instead of 3D surface reconstruction. With the growing need of tissue texture information for clinical purposes, the 3D reconstruction based on endoscopic images plays a more vital role than ever, especially in tumor diagnosis and surveillance of esophagus, lung, stomach, bladder and etc. In this work, new algorithms were developed to solve specific 3D reconstruction problems in biomedical applications. To reconstruct the 3D internal surface of a human organ, such as bladder or stomach, a sequence of 2D endoscopic images were captured by rotating and moving the scope around inside of the organs. This 3D reconstruction solely based on images is called Structure-from-Motion (SfM). To overcome the problems of insufficient features in medical images and short camera baselines, the camera poses were initially estimated by constraining the surface on a spherical shape at the first step. The more realistic organ surface was then reconstructed by releasing the spherical constraints. Extra features were built to handle multiple scanning videos and recover the physical scale of the 3D surface with reference lesion target. To reduce the human error and surgical operating time in removing the tumor/cancer in brain, a semi-automated surgical robotic system with 3D vision is being developed. By providing an accurate 3D surface model of the surgical field based on a RGB (red, green and blue) camera attached to the surgical tool, the robot could perform tedious operation of residual tumor tissue removal automatically. Camera position and orientation were also known throughout the surgery from the robotic system. This 3D reconstruction with known camera parameters is called Multi-view Stereo. Due to the mechanical limitation of robotic system, the camera pose parameters were with certain errors (tolerance). To utilize these inaccurate but bound constrained variables, Bound Constrained Bundle Adjustment (BCBA) algorithm was developed based on gradient projection to generate accurate 3D model efficiently. Besides biomedical applications, 3D computer vision is emerging in traditional industries, such as manufacture and quality control applications. To build a potential in-line 3D metrology tool for internal threads in automobile engine blocks, two 3D reconstruction algorithms were developed with forward-view and side-view cameras, respectively. Axial-stereo vision algorithm was proposed to create dense 3D point cloud of internal surface based on two forward-view images that are aligned on the optical axis. Feature-based panoramic 3D registration algorithm was developed to register different side-view image-generated 3D surface patches together, by taking advantage of the robustness and accuracy of SIFT features. Each side-view patch of the repeated geometry of a threaded hole was reconstructed by multi-view stereo. Comparing with traditional 3D point clouds registration algorithm Iterative Closest Point (ICP), our algorithm has the advantages of high-efficiency and high-accuracy, especially for the registration of repetitive geometries.

Download or read book Resolving Ambiguities in Monocular 3D Reconstruction of Deformable Surfaces written by Aydin Varol and published by . This book was released on 2012 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Markerless 3D Reconstruction of Temporally Deforming Surfaces from Multiple Cameras written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 3D content generation is a major challenge in computer graphics, and generating realistic objects with time-varying shape and motion is a big part of creating realistic virtual environments. An attractive approach for generating content is to acquire the shape of real objects using computer vision techniques. Capturing the real world avoids the complexity of mathematical simulation as well as the time-consuming and difficult process of creating content manually. Traditional acquisition methods, such as range scanning, work well for static objects. However, temporally deformable objects like garments and human faces pose greater challenges. Here, the capture process must reconstruct both the time-varying shape as well as the motion of the object. Additionally, per-frame texture maps should be acquired for realistic rendering. Previous methods contain various limitations, such as the use of structured illumination patterns, or hand-placed markers on the surface in order to guide the reconstruction. Placing markers on garments limits the types of garments that can be captured. Both markers and structured light on human faces limit the ability to capture high-quality per-frame texture maps, which are essential for reconstructing performance-specific details such as sweating, wrinkles and blood flow. In this thesis we propose new, entirely passive techniques for advancing the state-of-the-art in 3D reconstruction of temporally deformable surfaces. We reconstruct high-resolution, temporally compatible geometry using multiple video cameras, without the need for either markers or structured light patterns. This thesis contains several contributions, both in computer graphics as well as computer vision. We start with new methods for multi-camera calibration and synchronization, which allow us to employ inexpensive consumer video cameras for reconstruction. We also present a novel technique for multi-view stereo reconstruction, capable of building high-resolution geometric me.

Download or read book Pattern Recognition written by Thomas Brox and published by Springer. This book was released on 2019-02-15 with total page 717 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the refereed proceedings of the 40th German Conference on Pattern Recognition, GCPR 2018, held in Stuttgart, Germany, in October 2018. The 48 revised full papers presented were carefully reviewed and selected from 118 submissions. The German Conference on Pattern Recognition is the annual symposium of the German Association for Pattern Recognition (DAGM). It is the national venue for recent advances in image processing, pattern recognition, and computer vision and it follows the long tradition of the DAGM conference series, which has been renamed to GCPR in 2013 to reflect its increasing internationalization. In 2018 in Stuttgart, the conference series celebrated its 40th anniversary.

Download or read book Local Analytic and Global Convex Methods for the 3D Reconstruction of Isometric Deformable Surfaces written by Ajad Chhatkuli and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis contributes to the problem of 3D reconstruction for deformable surfaces using a single camera. In order to model surface deformation, we use the isometric prior because many real object deformations are near-isometric. Isometry implies that the surface cannot stretch or compress. We tackle two different problems. The first is called Shape-from-Template where the object's deformed shape is computed from a single image and a texture-mapped 3D template of the object surface. Previous methods propose a differential model of the problem and compute the local analytic solutions. In the methods the solution related to the depth-gradient is discarded and only the depth solution is used. We demonstrate that the depth solution lacks stability as the projection geometry tends to affine. We provide alternative methods based on the local analytic solutions of first-order quantities, such as the depth-gradient or surface normals. Our methods are stable in all projection geometries. The second type of problem, called Non-Rigid Shape-from-Motion is the more general templatefree reconstruction scenario. In this case one obtains the object's shapes from a set of images where it appears deformed. We contribute to this problem for both local and global solutions using the perspective camera. In the local or point-wise method, we solve for the surface normal at each point assuming infinitesimal planarity of the surface. We then compute the surface by integration. In the global method we find a convex relaxation of the problem. This is based on relaxing isometry to inextensibility and maximizing the surface's average depth. This solution combines all constraints into a single convex optimization program to compute depth and works for a sparse point representation of the surface. We detail the extensive experiments that were used to demonstrate the effectiveness of each of the proposed methods. The experiments show that our local template-free solution performs better than most of the previous methods. Our local template-based method and our global template-free method performs better than the state-of-the-art methods with robustness to correspondence noise. In particular, we are able to reconstruct difficult, non-smooth and articulating deformations with the latter; while with the former we can accurately reconstruct large deformations with images taken at very long focal lengths.

Download or read book Binocular Shading and Visual Surface Reconstruction written by William Eric Leifur Grimson and published by . This book was released on 1982 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zero-crossing or feature-point based stereo algorithms can, by definition, determine explicit depth information only at particular points in the image. To compute a complete surface description, this sparse depth map must be interpolated. A computational theory of this interpolation or reconstruction process, based on a surface consistency constraint, has previously been proposed. In order to provide stronger boundary conditions for the interpolation process, other visual cues to surface shape are examined in this paper. In particular, it is shown that, in principle, shading information from the two views can be used to determine the orientation of the surface normal along the feature-point contours, as well as the parameters of the reflective properties of the surface material. The numerical stability of the resulting equations is also examined. (Author).