Resolving Ambiguities in Monocular 3D Reconstruction of Deformable Surfaces

In this thesis, we focus on the problem of recovering 3D shapes of deformable surfaces from a single camera. This problem is known to be ill-posed as for a given 2D input image there exist many 3D shapes that give visually identical projections. We present three methods which make headway towards resolving these ambiguities. We believe that our work represents a significant step towards making surface reconstruction methods of practical use. First, we propose a surface reconstruction method that overcomes the limitations of the state-of-the-art template-based and non-rigid structure from motion methods. We neither track points over many frames, nor require a sophisticated deformation model, or depend on a reference image. In our method, we establish correspondences between pairs of frames in which the shape is different and unknown. We then estimate homographies between corresponding local planar patches in both images. These yield approximate 3D reconstructions of points within each patch up to a scale factor. Since we consider overlapping patches, we can enforce them to be consistent over the whole surface. Finally, a local deformation model is used to fit a triangulated mesh to the 3D point cloud, which makes the reconstruction robust to both noise and outliers in the image data. Second, we propose a novel approach to recovering the 3D shape of a deformable surface from a monocular input by taking advantage of shading information in more generic contexts than conventional Shape-from-Shading (SfS) methods. This includes surfaces that may be fully or partially textured and lit by arbitrarily many light sources. To this end, given a lighting model, we learn the relationship between a shading pattern and the corresponding local surface shape. At run time, we first use this knowledge to recover the shape of surface patches and then enforce spatial consistency between the patches to produce a global 3D shape. Instead of treating texture as noise as in many SfS approaches, we exploit it as an additional source of information. We validate our approach quantitatively and qualitatively using both synthetic and real data. Third, we introduce a constrained latent variable model that inherently accounts for geometric constraints such as inextensibility defined on the mesh model. To this end, we learn a non-linear mapping from the latent space to the output space, which corresponds to vertex positions of a mesh model, such that the generated outputs comply with equality and inequality constraints expressed in terms of the problem variables. Since its output is encouraged to satisfy such constraints inherently, using our model removes the need for computationally expensive methods that enforce these constraints at run time. In addition, our approach is completely generic and could be used in many other different contexts as well, such as image classification to impose separation of the classes, and articulated tracking to constrain the space of possible poses

Template-based Monocular 3-D Shape Reconstruction And Tracking Using Laplacian Meshes

This thesis addresses the problem of recovering the 3-D shape of a deformable object in single images, or image sequences acquired by a monocular video camera, given that a 3-D template shape and a template image of the object are available. While being a very challenging problem in computer vision, being able to reconstruct and track 3-D deformable objects in videos allows us to develop many potential applications ranging from sports and entertainments to engineering and medical imaging. This thesis extends the scope of deformable object modeling to real-world applications of fully 3-D modeling of deformable objects from video streams with a number of contributions. We show that by extending the Laplacian formalism, which was first introduced in the Graphics community to regularize 3-D meshes, we can turn the monocular 3-D shape reconstruction of a deformable object given correspondences with a reference image into a much better-posed problem with far fewer degrees of freedom than the original one. This has proved key to achieving real-time performance while preserving both sufficient flexibility and robustness. Our real-time 3-D reconstruction and tracking system of deformable objects can very quickly reject outlier correspondences and accurately reconstruct the object shape in 3D. Frame-to-frame tracking is exploited to track the object under difficult settings such as large deformations, occlusions, illumination changes, and motion blur. We present an approach to solving the problem of dense image registration and 3-D shape reconstruction of deformable objects in the presence of occlusions and minimal texture. A main ingredient is the pixel-wise relevancy score that we use to weigh the influence of the image information from a pixel in the image energy cost function. A careful design of the framework is essential for obtaining state-of-the-art results in recovering 3-D deformations of both well- and poorly-textured objects in the presence of occlusions. We study the problem of reconstructing 3-D deformable objects interacting with rigid ones. Imposing real physical constraints allows us to model the interactions of objects in the real world more accurately and more realistically. In particular, we study the problem of a ball colliding with a bat observed by high speed cameras. We provide quantitative measurements of the impact that are compared with simulation-based methods to evaluate which simulation predictions most accurately describe a physical quantity of interest and to improve the models. Based on the diffuse property of the tracked deformable object, we propose a method to estimate the environment irradiance map represented by a set of low frequency spherical harmonics. The obtained irradiance map can be used to realistically illuminate 2-D and 3-D virtual contents in the context of augmented reality on deformable objects. The results compare favorably with baseline methods. In collaboration with Disney Research, we develop an augmented reality coloring book application that runs in real-time on mobile devices. The app allows the children to see the coloring work by showing animated characters with texture lifted from their colors on the drawing. Deformations of the book page are explicitly modeled by our 3-D tracking and reconstruction method. As a result, accurate color information is extracted to synthesize the character's texture

Same Story Every Time / Being Black is Not a Crime : Gun Regulations and Recurrent Patterns of Government Control of Black Americans in the Nineteenth and Twentieth Centuries

Since the shooting death of Michael Brown in Ferguson, Missouri in August 2014, there has been a renewed national conversation on relations between law enforcement and communities of color. Subsequent shooting deaths of Black individuals, followed by grand jury non-indictments, have shifted the conversation to a systemic critique, revealing to some, and reminding others, of the deeply racialized nature of criminal justice in the United States. This thesis project is a work of American Political Development that analyzes the racialized developmental of the criminal justice system in the United States, providing context to the recent national conversation. Its purpose is to make sense of the institutionalized racism present in today’s criminal justice system by identifying concrete and detailed instances of institutionalized racism shaping the development of the criminal justice system historically. It identifies a specific racialized pattern in the system’s history: at moments of significant racial progress, there often occurs, through the criminal justice system, a “colorblind” backlash, designed to reassert and maintain control over those Black individuals enjoying racial progress. The scope of the project is limited both in policy area and time—it considers the suspect passage and implementation of “colorblind” gun laws with racialized effects at two critical junctures in America racial history, Reconstruction and the Civil Rights movement. The goal of the project is to at least in part explain the racialized nature of today’s criminal justice system by exploring how colorblindness and institutionalized racism have shaped its development and growth historically

Institutional change in Russian corporate governance: an analysis of corporate disputes

Russia has been lagging behind most of the developed countries and some of the transition economies in terms of the corporate governance infrastructure (Woodruff, 2004). However, the challenge to develop strategic assets, particularly in the form of oil and gas reserves, produced the need to attract foreign capital and expertise. This in turn has led to a mounting pressure to improve fundamental characteristics of corporate governance such as the regulatory environment, enforcement mechanisms, corporate structure and transparency (Preobragenskaya, 2004). Since strategic assets are at the very heart of the still undiversified Russian economy, it is easy to see how corporate governance has become one of the top priorities on the agenda of national reforms (EU-Russia Roundtable on Corporate Governance, 2006). This study attempts to register the perceived change in the institutional context in Russia through analysing reported corporate disputes. Thematic template analysis is applied to the data on corporate conflicts taken from the English language Russian press. The results of the study suggest a positive change in perception about the role of formal institutions with reference to private entities and a negative change in terms of perception in relation to state entities. This conclusion is based on the comparison of corporate disputes and enforcement practices employed by the parties to corporate disputes reported in 1998 and 2006. On an academic level this study addresses a call in the literature to give more consideration to the particularities of the management environment and the fragility of its social systems in Russia (Kuznetsov & Kuznetsova, 2001) as well as complement understanding of Russian corporate governance by concentrating on the in-depth analysis of company behaviour (Iwasaki, 2007)

Reframing unlawful controls: judicial impact on UK asylum and deportation policy, 1990-2012

Supra -national and municipal courts are increasingly involved in determining the parameters of European states' refugee and asylum policy. Yet, little attention has been paid to how and why governments choose to comply with judicial decisions which constrain their policy goals. In the UK, judicial oversight of asylum control has occasionally met with outspoken political opposition, which has even challenged the legitimacy of judicial scrutiny. Nevertheless, `compliance' typically follows. This makes it all the more important to consider how and why judicial decisions on the lawfulness of asylum and deportation controls do nevertheless impact upon policy change and its justification by government.To identify key mechanisms which condition the impact of judicial decisions on the politics and policies of asylum control, this thesis presents comparative qualitative case study research into UK government responses to European Court of Human Rights (ECtHR) and municipal court rulings which concern deportation and asylum control policies. Comparative consideration is given to significance attached by governments to the source of the ruling (UK / ECtHR) and whether compliance was politically contested. Politicisation and domestic rulings are each expected to allow greater governmental opposition to judicial impact on policy goals. To capture variation, my analysis differentiates judicial impact on two typological planes: governmental response and the level of generality of governing ideas 'at stake' therein. This mobilises the explanatory potential of governmental framings of `the problem' of compliance, in terms of how constraining it is perceived to be; whether removing a policy instrument which can be readily replaced, challenging the continuity of underlying programmatic logics, or even the guiding public philosophy informing deportation and asylum control. Where more general governing ideas are at stake, governmental responses can be expected to reflect opposition to judicial impact.Critical framing analysis of the government's discursive response is applied to four key cases, ranging from 1990 to 2012. Framing is presented as a necessarily observable process through which judicial impact is manifest within government, and can be traced. Specifically, I analyse how the 'problem' of compliance and its policy impact are framed in political rhetoric which responds to the courts and in documents through which government interprets and inscribes the meaning and implementation of judicial decisions. My findings suggest that whilst governance of asylum and deportation in the UK may labour under a judicial shadow, this has not precluded legal risk taking and efforts to `contain' the impact of individual rulings on the viability of the overarching policy regime. By identifying the role of governing ideas `at stake' in governmental framings of judicial impact, I argue that it is possible to account for varying political responses to the courts, including politicisation of compliance. Where impact is framed as more general, politicisation of compliance follows. In contrast, the source of the ruling appears to have no independent significance to responses. The importance of a distinction between judicial impact on justificatory political rhetoric and the practice of administrative compliance is also reinforced

Computer vision and optimization methods applied to the measurements of in-plane deformations

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Conceptualising beliefs and understanding their (mis)use in the forensic sciences

The growing forensic evidence base is often not fully reflected in the development of theories and the truth-finding process throughout the criminal justice system. This is worrying; it may lead to a misunderstanding of the meaning and value of the evidence by decision-makers, which has been shown to result in wrongful convictions on a significant scale. One of the justifications for the range of issues and concerns expressed over the years regarding the analysis, interpretation, and presentation of evidence includes a limited situational understanding of observations at that time. This thesis addresses the hypothesis that some misinterpretations (i.e. an invalid belief in an hypothesis given the evidence) could have been minimised. Four related approaches demonstrate that in many cases, better inferences and decisions could have been made. First, the legal, historical, logical, and knowledge-base perspectives on making reasonable and fair arguments from observations are explored. The challenges which need to be overcome between the law and sciences are demonstrated, and a case is made that fundamental theories of analyses and interpretations have not been studied sufficiently in the light of scientific approaches and reasoning processes. Second, a systematic study of Court of Appeal cases identifies that misleading evidence is a prevalent and sometimes avoidable issue in England and Wales. Examples include a misinterpretation and miscommunication of the relevance, probative value, and validity of evidence. Third, to explore the misuse of evidence more in-depth, a novel conceptual framework incorporating key components of interpretations from trace scripts is developed, allowing for systematic approaches to evaluating interpretations. Fourth, this framework is applied to the interpretation of geo-forensic evidence. It is demonstrated that the approaches taken to study uncertainties and the effects of these approaches on the expression of beliefs and decision-making processes are not always sufficiently taken or transparently presented