Inverse rendering for scene reconstruction in general environments

Demand for high-quality 3D content has been exploding recently, owing to the advances in 3D displays and 3D printing. However, due to insufficient 3D content, the potential of 3D display and printing technology has not been realized to its full extent. Techniques for capturing the real world, which are able to generate 3D models from captured images or videos, are a hot research topic in computer graphics and computer vision. Despite significant progress, many methods are still highly constrained and require lots of prerequisites to succeed. Marker-less performance capture is one such dynamic scene reconstruction technique that is still confined to studio environments. The requirements involved, such as the need for a multi-view camera setup, specially engineered lighting or green-screen backgrounds, prevent these methods from being widely used by the film industry or even by ordinary consumers. In the area of scene reconstruction from images or videos, this thesis proposes new techniques that succeed in general environments, even using as few as two cameras. Contributions are made in terms of reducing the constraints of marker-less performance capture on lighting, background and the required number of cameras. The primary theoretical contribution lies in the investigation of light transport mechanisms for high-quality 3D reconstruction in general environments. Several steps are taken to approach the goal of scene reconstruction in general environments. At first, the concept of employing inverse rendering for scene reconstruction is demonstrated on static scenes, where a high-quality multi-view 3D reconstruction method under general unknown illumination is developed. Then, this concept is extended to dynamic scene reconstruction from multi-view video, where detailed 3D models of dynamic scenes can be captured under general and even varying lighting, and in front of a general scene background without a green screen. Finally, efforts are made to reduce the number of cameras employed. New performance capture methods using as few as two cameras are proposed to capture high-quality 3D geometry in general environments, even outdoors.Die Nachfrage nach qualitativ hochwertigen 3D Modellen ist in letzter Zeit, bedingt durch den technologischen Fortschritt bei 3D-Wieder-gabegeräten und -Druckern, stark angestiegen. Allerdings konnten diese Technologien wegen mangelnder Inhalte nicht ihr volles Potential entwickeln. Methoden zur Erfassung der realen Welt, welche 3D-Modelle aus Bildern oder Videos generieren, sind daher ein brandaktuelles Forschungsthema im Bereich Computergrafik und Bildverstehen. Trotz erheblichen Fortschritts in dieser Richtung sind viele Methoden noch stark eingeschränkt und benötigen viele Voraussetzungen um erfolgreich zu sein. Markerloses Performance Capturing ist ein solches Verfahren, das dynamische Szenen rekonstruiert, aber noch auf Studio-Umgebungen beschränkt ist. Die spezifischen Anforderung solcher Verfahren, wie zum Beispiel einen Mehrkameraaufbau, maßgeschneiderte, kontrollierte Beleuchtung oder Greenscreen-Hintergründe verhindern die Verbreitung dieser Verfahren in der Filmindustrie und besonders bei Endbenutzern. Im Bereich der Szenenrekonstruktion aus Bildern oder Videos schlägt diese Dissertation neue Methoden vor, welche in beliebigen Umgebungen und auch mit nur wenigen (zwei) Kameras funktionieren. Dazu werden Schritte unternommen, um die Einschränkungen bisheriger Verfahren des markerlosen Performance Capturings im Hinblick auf Beleuchtung, Hintergründe und die erforderliche Anzahl von Kameras zu verringern. Der wichtigste theoretische Beitrag liegt in der Untersuchung von Licht-Transportmechanismen für hochwertige 3D-Rekonstruktionen in beliebigen Umgebungen. Dabei werden mehrere Schritte unternommen, um das Ziel der Szenenrekonstruktion in beliebigen Umgebungen anzugehen. Zunächst wird die Anwendung von inversem Rendering auf die Rekonstruktion von statischen Szenen dargelegt, indem ein hochwertiges 3D-Rekonstruktionsverfahren aus Mehransichtsaufnahmen unter beliebiger, unbekannter Beleuchtung entwickelt wird. Dann wird dieses Konzept auf die dynamische Szenenrekonstruktion basierend auf Mehransichtsvideos erweitert, wobei detaillierte 3D-Modelle von dynamischen Szenen unter beliebiger und auch veränderlicher Beleuchtung vor einem allgemeinen Hintergrund ohne Greenscreen erfasst werden. Schließlich werden Anstrengungen unternommen die Anzahl der eingesetzten Kameras zu reduzieren. Dazu werden neue Verfahren des Performance Capturings, unter Verwendung von lediglich zwei Kameras vorgeschlagen, um hochwertige 3D-Geometrie im beliebigen Umgebungen, sowie im Freien, zu erfassen

Id2 promotes the invasive growth of MCF-7 and SKOV-3 cells by a novel mechanism independent of dimerization to basic helix-loop-helix factors

<p>Abstract</p> <p>Background</p> <p>Inhibitor of differentiation 2 (<it>Id2</it>) is a critical factor for cell proliferation and differentiation in normal vertebrate development. Most of the biological function of Id2 has been ascribed to its helix-loop-helix motif. Overexpression of Id2 is frequently observed in various human tumors, but its role for invasion potential in tumor cells is dispute. We aimed to reveal the role of Id2 in invasion potential in poorly invasive and estrogen receptor α (ERα)-positive MCF-7 and SKOV-3 cancer cells.</p> <p>Methods</p> <p>MCF-7 and SKOV-3 cells were stably transfected with the wild-type, degradation-resistant full-length or helix-loop-helix (HLH)-deleted Id2, respectively. Protein levels of Id2 and its mutants and E-cadherin were determined by western blot analysis and mRNA levels of Id2 and its mutants were determined by RT-PCR. The effects of Id2 and its mutants on cell proliferation were determined by [³H]-thymidine incorporation assay and the 3- [4, 5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) dye method. The <it>in vitro </it>invasion potential of cells was evaluated by Transwell assay. Cell motility was assessed by scratch wound assay. The promoter activity of <it>E-cadherin </it>was determined by cotransfection and luciferase assays.</p> <p>Results</p> <p>Ectopic transfection of the wild-type Id2 markedly increased the protein and mRNA expression of <it>Id2 </it>in MCF-7 and SKOV-3 cells; the protein level but not mRNA level was further increased by transfection with the degradation-resistant Id2 form. The ectopic expression of Id2 or its mutants did not alter proliferation of either MCF-7 or SKOV-3 cells. Transfection of the wild-type Id2 significantly induced the invasion potential and migratory capacity of cells, which was further augmented by transfection with the degradation-resistant full-length or HLH-deleted Id2. E-cadherin protein expression and transactivation of the proximal E-cadherin promoter were markedly suppressed by the degradation-resistant full-length or HLH-deleted Id2 but not wild-type Id2. Ectopic expression of E-cadherin in MCF-7 and SKOV-3 cells only partially blunted the invasion potential induced by the degradation-resistant HLH-deleted Id2.</p> <p>Conclusion</p> <p>Overexpression of Id2 in ERα-positive epithelial tumor cells indeed increases the cells' invasive potential through a novel mechanism independent of dimerization to basic helix-loop-helix factors. E-cadherin contributes only in part to Id2-induced cell invasion when Id2 is accumulated to a higher level in some specific cell types.</p

Diverse biological effects of glycosyltransferase genes from Tartary buckwheat

Background: Tartary buckwheat (Fagopyrum tataricum) is an edible cereal crop whose sprouts have been marketed and commercialized for their higher levels of anti-oxidants, including rutin and anthocyanin. UDP-glucose flavonoid glycosyltransferases (UFGTs) play an important role in the biosynthesis of flavonoids in plants. So far, few studies are available on UFGT genes that may play a role in tartary buckwheat flavonoids biosynthesis. Here, we report on the identification and functional characterization of seven UFGTs from tartary buckwheat that are potentially involved in flavonoid biosynthesis (and have varying effects on plant growth and development when overexpressed in Arabidopsis thaliana.) Results: Phylogenetic analysis indicated that the potential function of the seven FtUFGT proteins, FtUFGT6, FtUFGT7, FtUFGT8, FtUFGT9, FtUFGT15, FtUFGT40, and FtUFGT41, could be divided into three Arabidopsis thaliana functional subgroups that are involved in flavonoid biosynthesis of and anthocyanin accumulation. A significant positive correlation between FtUFGT8 and FtUFGT15 expression and anthocyanin accumulation capacity was observed in the tartary buckwheat seedlings after cold stress. Overexpression in Arabidopsis thaliana showed that FtUFGT8, FtUFGT15, and FtUFGT41 significantly increased the anthocyanin content in transgenic plants. Unexpectedly, overexpression of FtUFGT6, while not leading to enhanced anthocyanin accumulation, significantly enhanced the growth yield of transgenic plants. When wild-type plants have only cotyledons, most of the transgenic plants of FtUFGT6 had grown true leaves. Moreover, the growth speed of the oxFtUFGT6 transgenic plant root was also significantly faster than that of the wild type. At later growth, FtUFGT6 transgenic plants showed larger leaves, earlier twitching times and more tillers than wild type, whereas FtUFGT15 showed opposite results. Conclusions: Seven FtUFGTs were isolated from tartary buckwheat. FtUFGT8, FtUFGT15, and FtUFGT41 can significantly increase the accumulation of total anthocyanins in transgenic plants. Furthermore, overexpression of FtUFGT6 increased the overall yield of Arabidopsis transgenic plants at all growth stages. However, FtUFGT15 shows the opposite trend at later growth stage and delays the growth speed of plants. These results suggested that the biological function of FtUFGT genes in tartary buckwheat is diverse

Diffusion Shape Prior for Wrinkle-Accurate Cloth Registration

Registering clothes from 4D scans with vertex-accurate correspondence is challenging, yet important for dynamic appearance modeling and physics parameter estimation from real-world data. However, previous methods either rely on texture information, which is not always reliable, or achieve only coarse-level alignment. In this work, we present a novel approach to enabling accurate surface registration of texture-less clothes with large deformation. Our key idea is to effectively leverage a shape prior learned from pre-captured clothing using diffusion models. We also propose a multi-stage guidance scheme based on learned functional maps, which stabilizes registration for large-scale deformation even when they vary significantly from training data. Using high-fidelity real captured clothes, our experiments show that the proposed approach based on diffusion models generalizes better than surface registration with VAE or PCA-based priors, outperforming both optimization-based and learning-based non-rigid registration methods for both interpolation and extrapolation tests.Comment: Project page: https://www-users.cse.umn.edu/~guo00109/projects/3dv2024