Image-based Modeling Approach Research Articles

IFWB: A Simple Image-Based Modeling Approach to Breaking the “Fourth Wall”

本論文では, ユーザが注目対象の画像（図1(a)）に対して臨場感をもち得ていない心理的状態「第四の壁」を, 画像内の世界へのウォークスルー体験（図1(b)）を実現することによって壊すイメージベースモデリングシステムとして, IFWB (Instant Fourth Wall Breaker) を提案する. 本システムは, 奥行きのある構図をもつ画像を1 枚入力すると, それ以上のユーザ入力を必要とすることなく即座に動作する. 実際のターゲット環境として, スマートフォンやタブレット端末などの軽薄短小なデバイスを想定しており, カメラと同じような感覚で, いつでもどこでも使うことができる（図1(c)）.

Influence of dental restorations and mastication loadings on dentine fatigue behaviour: Image-based modelling approach

ObjectivesThe aim of this study was to use Finite Element Analysis (FEA) to estimate the influence of various mastication loads and different tooth treatments (composite restoration and endodontic treatment) on dentine fatigue. The analysis of fatigue behaviour of human dentine in intact and composite restored teeth with root-canal-treatment using FEA and fatigue theory was performed. MethodsDentine fatigue behaviour was analysed in three virtual models: intact, composite-restored and endodontically-treated tooth. Volumetric change during the polymerization of composite was modelled by thermal expansion in a heat transfer analysis. Low and high shrinkage stresses were obtained by varying the linear shrinkage of composite. Mastication forces were applied occlusally with the load of 100, 150 and 200N. Assuming one million cycles, Fatigue Failure Index (FFI) was determined using Goodman's criterion while residual fatigue lifetime assessment was performed using Paris-power law. ResultsThe analysis of the Goodman diagram gave both maximal allowed crack size and maximal number of cycles for the given stress ratio. The size of cracks was measured on virtual models. For the given conditions, fatigue-failure is not likely to happen neither in the intact tooth nor in treated teeth with low shrinkage stress. In the cases of high shrinkage stress, crack length was much larger than the maximal allowed crack and failure occurred with 150 and 200N loads. The maximal allowed crack size was slightly lower in the tooth with root canal treatment which induced somewhat higher FFI than in the case of tooth with only composite restoration. ConclusionsMain factors that lead to dentine fatigue are levels of occlusal load and polymerization stress. However, root canal treatment has small influence on dentine fatigue. Clinical significanceThe methodology proposed in this study provides a new insight into the fatigue behaviour of teeth after dental treatments. Furthermore, it estimates maximal allowed crack size and maximal number of cycles for a specific case.

Three-dimensional numerical modeling of ultrasonic wave propagation in concrete and its experimental validation

To understand the characteristics of ultrasonic wave propagation in concrete more completely, we propose a time domain simulation tool based on the finite integration technique (FIT) and an image-based modeling approach. When modeling ultrasonic wave propagation in concrete, it is important to introduce three-dimensional mesoscopic and microscopic structures because ultrasonic waves in solids are transmitted by mechanical interaction between adjacent media. In this paper, wave velocity, center frequency, and attenuation of ultrasonic waves in concrete are evaluated quantitatively by comparing the waveforms obtained by FIT simulation with those obtained by experimental measurement. It was observed that these factors were in good agreement between the simulation and measurements. It was also observed that amplitude of the transmitted signal was sensitive to the allocation pattern of the aggregates. Thus, attenuation due to multiple scattering by aggregates is more dominant than the attenuation by intrinsic absorption and geometrical spreading in concrete.

Image-Based Modeling Approaches to 2D and 3D Digital Drafting in Archaeology at Tel Akko and Qasrin

ABSTRACT As archaeologists continue to adopt geographic information systems and computer-aided design software packages to record and store spatial data, excavations have begun to forgo hand-drawn plans in favor of digital recording. The purpose of this article is to present two case studies that have successfully utilized digital drafting techniques to create architectural plans at multiple scales. The first presents on-site 2D and 3D documentation at the site of Tel Akko, Israel, at the square, field, and tell scales. The second study combines orthophotos and legacy data to create an accurate site plan of Qasrin on the Golan Heights. Both harness image-based modeling to produce 2D and 3D spatial data in order to produce top plans with unprecedented spatial accuracy.

Historical Single Image-Based Modeling: The Case of Gobierna Tower, Zamora (Spain)

Historical perspective images have been proved to be very useful to properly provide a dimensional analysis of buildings façades or even to generate a pseudo-3D reconstruction based on rectified images of the whole structure. In this paper, the case of Gobierna Tower (Zamora, Spain) is analyzed from a historical single image-based modeling approach. In particular, a bottom-up approach, which takes advantage from the perspective of the image, the existence of the three vanishing points and the usual geometric constraints (i.e., planarity, orthogonality, and parallelism) is applied for the dimensional analysis of a destroyed historical building. Results were compared with ground truth measurements existing in a historical topographical surveying obtaining deviations of about 1%.

Finite integration technique for coupled acoustic and elastic wave simulation and its application to noncontact ultrasonic testing

To better understand wave propagation and scattering phenomena in noncontact ultrasonic testing (UT), we have developed a time domain simulation tool to model wave propagation in air and solids. The tool is based on the finite integration technique (FIT) and an image-based modeling approach. The image-based FIT can treat the calculation of acoustic, elastic, and coupled waves in a unified grid form. In this paper, we first investigate the accuracy of the interface condition in FIT modeling by comparing numerical results with analytical solutions of transmission and reflection coefficients. Then we validate the FIT using measured signals in guided wave testing with air-coupled transducers. To simulate noncontact UT, a fine mesh is required in the FIT because the wavelength in air is much smaller than that in a solid. To solve the numerical problem with the finer mesh at high speed, we introduce a parallel computation technique with general-purpose computing on graphics processing units (GPUs). It is shown that the noncontact UT simulation can be executed within a reasonable time and with reasonable accuracy using multiple GPUs.

Development of patient specific implants for Minimum Invasive Spine Surgeries (MISS) from non-invasive imaging techniques by reverse engineering and additive manufacturing techniques

Reverse Engineering and Rapid Prototyping are extensively used technologies by both research and industrial community for rapid developments in various industrial as well as Bio-medical applications. Recent advances in computer technology and Bio-medicines enabled Computer Aided Design (CAD) to find many novel applications in Bio-medical engineering and integration of CAD and Bio-medical technology is usually referred as Bio-CAD. The major objective of the current research work is to generate an efficient algorithm for generation of free form surface from non-invasive CT scan images. Minimally Invasive Spine Surgery (MISS) have enabled spinal surgeons to select patients and treat several spinal disorders like degenerative disc disease, herniated disc, fractures, tumors, infections, instability, deformity, etc. with less disruption of muscles, which enables patient towards faster recovery to normal functions, reduces operative blood loss. In this paper, it is proposed to extract point cloud data from stalk of non-invasive CT scan images by using Image Processing techniques and Reverse Engineering approach. This point cloud data is to be processed for noise reduction, point cloud data segmentation and CAD model generation. This image-based CAD modeling approach begins with the acquisition of CT scan in DICOM 3.0 format. The point cloud estimation is based on threshold techniques and edge detection method. This point cloud data is used for construction of 3D CAD model by fitting free form NURB surface between theses points and then fitting surface between these curve networks by swept blend technique. An efficient and robust algorithm has been developed for generation of curves from unorganized point cloud data.

FUSION OF AIRBORNE AND TERRESTRIAL IMAGE-BASED 3D MODELLING FOR ROAD INFRASTRUCTURE MANAGEMENT – VISION AND FIRST EXPERIMENTS

Abstract. In this paper we present the vision and proof of concept of a seamless image-based 3d modelling approach fusing airborne and mobile terrestrial imagery. The proposed fusion relies on dense stereo matching for extracting 3d point clouds which – in combination with the original airborne and terrestrial stereo imagery – create a rich 3d geoinformation and 3d measuring space. For the seamless exploitation of this space we propose using a new virtual globe technology integrating the airborne and terrestrial stereoscopic imagery with the derived 3d point clouds. The concept is applied to road and road infrastructure management and evaluated in a highway mapping project combining stereovision based mobile mapping with high-resolution multispectral airborne road corridor mapping using the new Leica RCD30 sensor.

Fast Joint Estimation of Silhouettes and Dense 3D Geometry from Multiple Images

We propose a probabilistic formulation of joint silhouette extraction and 3D reconstruction given a series of calibrated 2D images. Instead of segmenting each image separately in order to construct a 3D surface consistent with the estimated silhouettes, we compute the most probable 3D shape that gives rise to the observed color information. The probabilistic framework, based on Bayesian inference, enables robust 3D reconstruction by optimally taking into account the contribution of all views. We solve the arising maximum a posteriori shape inference in a globally optimal manner by convex relaxation techniques in a spatially continuous representation. For an interactively provided user input in the form of scribbles specifying foreground and background regions, we build corresponding color distributions as multivariate Gaussians and find a volume occupancy that best fits to this data in a variational sense. Compared to classical methods for silhouette-based multiview reconstruction, the proposed approach does not depend on initialization and enjoys significant resilience to violations of the model assumptions due to background clutter, specular reflections, and camera sensor perturbations. In experiments on several real-world data sets, we show that exploiting a silhouette coherency criterion in a multiview setting allows for dramatic improvements of silhouette quality over independent 2D segmentations without any significant increase of computational efforts. This results in more accurate visual hull estimation, needed by a multitude of image-based modeling approaches. We made use of recent advances in parallel computing with a GPU implementation of the proposed method generating reconstructions on volume grids of more than 20 million voxels in up to 4.41 seconds.

Changes in articular cartilage mechanics with meniscectomy: A novel image-based modeling approach and comparison to patterns of OA

Meniscectomy is a significant risk factor for osteoarthritis, involving altered cell synthesis, central fibrillation, and peripheral osteophyte formation. Though changes in articular cartilage contact pressure are known, changes in tissue-level mechanical parameters within articular cartilage are not well understood. Recent imaging research has revealed the effects of meniscectomy on the time-dependent deformation of physiologically loaded articular cartilage. To determine tissue-level cartilage mechanics that underlie observed deformation, a novel finite element modeling approach using imaging data and a contacting indenter boundary condition was developed. The indenter method reproduces observed articular surface deformation and avoids assumptions about tangential stretching. Comparison of results from an indenter model with a traditional femur–tibia model verified the method, giving errors in displacement, solid and fluid stress, and strain below 1% (RMS) and 7% (max.) of the absolute maximum of the parameters of interest. Indenter finite element models using real joint image data showed increased fluid pressure, fluid exudation, loss of fluid load support, and increased tensile strains centrally on the tibial condyle after meniscectomy—patterns corresponding to clinical observations of cartilage matrix damage and fibrillation. Peripherally there was decreased consolidation, which corresponds to reduced contact and fluid pressure in this analysis. Clinically, these areas have exhibited advance of the subchondral growth front, biological destruction of the cartilage matrix, cartilage thinning, and eventual replacement of the cartilage via endochondral ossification. Characterizing the changes in cartilage mechanics with meniscectomy and correspondence with observed tissue-level effects may help elucidate the etiology of joint-level degradation seen in osteoarthritis.

Image-based modeling approach in creating 3D morphogenetic reconstruction of Liberty Square in Novi Sad

Abstract In this paper, various methods were combined to create a morphogenetic reconstruction of Liberty Square in Novi Sad using photo documentation as input data. Three-dimensional morphogenetic reconstruction of the city square provides the most comprehensive way of tracking changes in its structure through relative time periods. Transformations of Liberty Square are followed from the year 1885 to present day. Through that period, Liberty Square has undergone dramatic changes in its shape and structure. Previous appearances of the square are known from preserved historical photographs and mapping documentation. Old photographs and new digitally captured images were combined through different modeling approaches in attempt to find the most efficient way to reconstruct characteristic development phases of the square. Existing objects are generated through the use of different styles of photogrammetric modeling; however, non-existing or modified objects are generated by application of historical photo restitution combined with 3D modeling. Adequate simultaneous usage of all methods provides optimal results.

2213 大規模点群に基づくインタラクティブな形状モデリングシステム(OS4-1 デジタルモックアップ,OS4 デジタルエンジニアリング)

Mid-range and long-range laser scanners are useful for measuring large-scale engineering facilities. In this paper, we discuss a solid modeling system based on point-clouds captured from engineering facilities. When an engineering facility is measured by a laser scanner, the location of the scanner is restricted in most cases. Components of the engineering facility are only scanned from one side, and they are sometimes partially occluded by other components. To construct solid models using incomplete point-clouds, we propose a new image-based modeling approach combined with point-based modeling techniques. Since point-clouds captured by mid/long-range scanners have reflectance values as well as coordinates, their reflectance images can be used for image-based modeling. We show that our image-based modeling approach is useful for interactively complementing missing information. In addition, we show how to extract shape parameters as precisely as possible by considering industrial standards, assembly constraints, and user-specified constraints.

Turning images into 3-D models

In this article developments and performance analysis of image matching for detailed surface reconstruction of heritage objects is discussed. Three dimensional image-based modeling of heritages is a very interesting topic with many possible applications. In this article we propose a multistage image-based modeling approach that requires only a limited amount of human interactivity and is capable of capturing the fine geometric details with similar accuracy as close-range active range sensors. It can also cope with wide baselines using several advancements over standard stereo matching techniques. Our approach is sequential, starting from a sparse basic segmented model created with a small number of interactively measured points. This model, specifically the equation of each surface, is then used as a guide to automatically add the fine details. The following three techniques are used, each where best suited, to retrieve the details: 1) for regularly shaped patches such as planes, cylinders, or quadrics, we apply a fast relative stereo matching technique. 2) For more complex or irregular segments with unknown shape, we use a global multi-image geometrically constrained technique. 3) For segments unsuited for stereo matching, we employ depth from shading (DFS). The goal is not the development of a fully automated procedure for 3D object reconstruction from image data or a sparse stereo approach, but we aim at the digital reconstruction of detailed and accurate surfaces from calibrated and oriented images for practical daily documentation and digital conservation of wide variety of heritage objects.

Reconstruction of carotid bifurcation hemodynamics and wall thickness using computational fluid dynamics and MRI.

A thorough understanding of the relationship between local hemodynamics and plaque progression has been hindered by an inability to prospectively monitor these factors in vivo in humans. In this study a novel approach for noninvasively reconstructing artery wall thickness and local hemodynamics at the human carotid bifurcation is presented. Three-dimensional (3D) models of the lumen and wall boundaries, from which wall thickness can be measured, were reconstructed from black-blood magnetic resonance imaging (MRI). Along with time-varying inlet/outlet flow rates measured via phase contrast (PC) MRI, the lumen boundary was used as input for computational fluid dynamic (CFD) simulation of the subject-specific flow patterns and wall shear stresses (WSSs). Results from a 59-year-old subject with early, asymptomatic carotid artery disease show good agreement between simulated and measured velocities, and demonstrate a correspondence between wall thickening and low and oscillating shear at the carotid bulb. High shear at the distal internal carotid artery (ICA) was also colocalized with higher WSS; however, a quantitative general relationship between WSS and wall thickness was not found. Similar results were obtained from a 23-year-old normal subject. These findings represent the first direct comparison of hemodynamic variables and wall thickness at the carotid bifurcation of human subjects. The noninvasive nature of this image-based modeling approach makes it ideal for carrying out future prospective studies of hemodynamics and plaque development or progression in otherwise healthy subjects.

Visual modeling for computer animation

Over the past decade, the Visual Modeling Research Program at the University of Toronto has consistently championed the concerted exploration of computer graphics and computer vision. Our premise has been this: graphics, the forward/synthesis/models-to-images problem, and vision, the inverse/analysis/images-to-models problem, pose mutually converse challenges, which may best be tackled synergistically through the development of advanced modeling techniques catering to the needs of both fields. With illustrated case studies of three projects spanning a twelve-year period, this brief article presents a personal retrospective on image-based modeling for computer animation. As we shall see, one of the projects has also created opportunities for computer animation to contribute to the study of visual perception in living systems.I shall begin by reviewing an early computer animation project that pioneered the use of image-based modeling to combine natural and synthetic imagery. The animation Cooking with Kurt, produced in 1987 at the Schlumberger Palo Alto Research center, introduced a paradigm in which computer vision was applied to acquire 3D models of objects from their images. The acquired models were then dynamically animated in a simulated physical scene reconstructed from the image of a real scene. The approach demonstrated a promising alternative to the established convention of keyframe animating manually constructed geometric models.The human face is a natural objective for the image-based modeling approach. I will next describe a facial animation project that uses specialized imaging devices to capture models of human heads with functional, biomechanically simulated faces conforming closely to human subjects. Facial animation is by no means the sole benefactor of an exciting area of advanced graphics modeling that lies at the intersection of virtual reality and artificial life [6]. Accordingly, I will also describe a virtual "seaquarium" populated by artificial marine animals whose 3D shapes and appearances were captured from images of real fishes. As I discuss in the final section, lifelike, self-animating creatures now serve as biomimetic autonomous agents in the study of animal perception.