OmniSDF: Scene Reconstruction using Omnidirectional Signed Distance Functions and Adaptive Binoctrees

We present a method to reconstruct indoor and outdoor static scene geometry and appearance from an omnidirectional video moving in a small circular sweep. This setting is challenging because of the small baseline and large depth ranges, making it difficult to find ray crossings. To better constrain the optimization, we estimate geometry as a signed distance field within a spherical binoctree data structure and use a complementary efficient tree traversal strategy based on a breadth-first search for sampling. Unlike regular grids or trees, the shape of this structure well-matches the camera setting, creating a better memory-quality trade-off. From an initial depth estimate, the binoctree is adaptively subdivided throughout the optimization; previous methods use a fixed depth that leaves the scene undersampled. In comparison with three neural optimization methods and two non-neural methods, ours shows decreased geometry error on average, especially in a detailed scene, while significantly reducing the required number of voxels to represent such details

Progressively Optimized Local Radiance Fields for Robust View Synthesis

We present an algorithm for reconstructing the radiance field of a large-scale scene from a single casually captured video. The task poses two core challenges. First, most existing radiance field reconstruction approaches rely on accurate pre-estimated camera poses from Structure-from-Motion algorithms, which frequently fail on in-the-wild videos. Second, using a single, global radiance field with finite representational capacity does not scale to longer trajectories in an unbounded scene. For handling unknown poses, we jointly estimate the camera poses with radiance field in a progressive manner. We show that progressive optimization significantly improves the robustness of the reconstruction. For handling large unbounded scenes, we dynamically allocate new local radiance fields trained with frames within a temporal window. This further improves robustness (e.g., performs well even under moderate pose drifts) and allows us to scale to large scenes. Our extensive evaluation on the Tanks and Temples dataset and our collected outdoor dataset, Static Hikes, show that our approach compares favorably with the state-of-the-art.Comment: Project page: https://localrf.github.io

gVirtualXRay: Virtual X-Ray Imaging Library on GPU

International audienceWe present an Open-source library called gVirtualXRay to simulate realistic X-ray images in realtime. It implements the attenuation law (also called Beer-Lambert) on GPU. It takes into account the polychromatism of the beam spectra as well as the finite size of X-ray tubes. The library is written in C++ using modern OpenGL. It is fully portable and works on most common desktop/laptop computers. It has been tested on MS Windows, Linux, and Mac OS X. It supports a wide range of windowing solutions, such as FLTK, GLUT, GLFW3, Qt4, and Qt5. The library also offers realistic visual rendering of anatomical structures, including bones, liver, diaphragm and lungs. The accuracy of the X-ray images produced by gVirtualXRay's implementation has been validated using Geant4, a well established state-of-the-art Monte Carlo simulation toolkit developed by CERN. gVirtualXRay can be used in a wide range of applications where fast and accurate X-ray simulations from polygon meshes are needed, e.g. medical simulators for training purposes, simulation of tomography data acquisition with patient motion to include artefacts in reconstructed CT images, and deformable registration. Our application example package includes real-time respiration and X-ray simulation, CT acquisition and reconstruction, and iso-surfacing of implicit functions using Marching Cubes

Associations between depressive symptoms and disease progression in older patients with chronic kidney disease: results of the EQUAL study

Background Depressive symptoms are associated with adverse clinical outcomes in patients with end-stage kidney disease; however, few small studies have examined this association in patients with earlier phases of chronic kidney disease (CKD). We studied associations between baseline depressive symptoms and clinical outcomes in older patients with advanced CKD and examined whether these associations differed depending on sex. Methods CKD patients (>= 65 years; estimated glomerular filtration rate <= 20 mL/min/1.73 m(2)) were included from a European multicentre prospective cohort between 2012 and 2019. Depressive symptoms were measured by the five-item Mental Health Inventory (cut-off <= 70; 0-100 scale). Cox proportional hazard analysis was used to study associations between depressive symptoms and time to dialysis initiation, all-cause mortality and these outcomes combined. A joint model was used to study the association between depressive symptoms and kidney function over time. Analyses were adjusted for potential baseline confounders. Results Overall kidney function decline in 1326 patients was -0.12 mL/min/1.73 m(2)/month. A total of 515 patients showed depressive symptoms. No significant association was found between depressive symptoms and kidney function over time (P = 0.08). Unlike women, men with depressive symptoms had an increased mortality rate compared with those without symptoms [adjusted hazard ratio 1.41 (95% confidence interval 1.03-1.93)]. Depressive symptoms were not significantly associated with a higher hazard of dialysis initiation, or with the combined outcome (i.e. dialysis initiation and all-cause mortality). Conclusions There was no significant association between depressive symptoms at baseline and decline in kidney function over time in older patients with advanced CKD. Depressive symptoms at baseline were associated with a higher mortality rate in men

Nuclear architecture organized by Rif1 underpins the replication-timing program

DNA replication is temporally and spatially organized in all eukaryotes, yet the molecular control and biological function of the replication-timing program are unclear. Rif1 is required for normal genome-wide regulation of replication timing, but its molecular function is poorly understood. Here we show that in mouse embryonic stem cells, Rif1 coats late-replicating domains and, with Lamin B1, identifies most of the late-replicating genome. Rif1 is an essential determinant of replication timing of non-Lamin B1-bound late domains. We further demonstrate that Rif1 defines and restricts the interactions between replication-timing domains during the G1 phase, thereby revealing a function of Rif1 as organizer of nuclear architecture. Rif1 loss affects both number and replication-timing specificity of the interactions between replication-timing domains. In addition, during the S phase, Rif1 ensures that replication of interacting domains is temporally coordinated. In summary, our study identifies Rif1 as the molecular link between nuclear architecture and replication-timing establishment in mammals

Single-shot monocular RGB-D imaging using uneven double refraction

Cameras that capture color and depth information have become an essential imaging modality for applications in robotics, autonomous driving, virtual, and augmented reality. Existing RGB-D cameras rely on multiple sensors or active illumination with specialized sensors. In this work, we propose a method for monocular single-shot RGB-D imaging. Instead of learning depth from single-image depth cues, we revisit double-refraction imaging using a birefractive medium, measuring depth as the displacement of differently refracted images superimposed in a single capture. However, existing double-refraction methods are orders of magnitudes too slow to be used in real-time applications, e.g., in robotics, and provide only inaccurate depth due to correspondence ambiguity in double reflection. We resolve this ambiguity optically by leveraging the orthogonality of the two linearly polarized rays in double refraction - introducing uneven double refraction by adding a linear polarizer to the birefractive medium. Doing so makes it possible to develop a real-time method for reconstructing sparse depth and color simultaneously in real-time. We validate the proposed method, both synthetically and experimentally, and demonstrate 3D object detection and photographic applications.1

A Hierarchical 3D Gaussian Representation for Real-Time Rendering of Very Large Datasets

OPAL-MesoInternational audienceNovel view synthesis has seen major advances in recent years, with 3D Gaussian splatting offering an excellent level of visual quality, fast training and real-time rendering. However, the resources needed for training and rendering inevitably limit the size of the captured scenes that can be represented with good visual quality. We introduce a hierarchy of 3D Gaussians that preserves visual quality for very large scenes, while offering an efficient Level-of-Detail (LOD) solution for efficient rendering of distant content with effective level selection and smooth transitions between levels.We introduce a divide-and-conquer approach that allows us to train very large scenes in independent chunks. We consolidate the chunks into a hierarchy that can be optimized to further improve visual quality of Gaussians merged into intermediate nodes. Very large captures typically have sparse coverage of the scene, presenting many challenges to the original 3D Gaussian splatting training method; we adapt and regularize training to account for these issues. We present a complete solution, that enables real-time rendering of very large scenes and can adapt to available resources thanks to our LOD method. We show results for captured scenes with up to tens of thousands of images with a simple and affordable rig, covering trajectories of up to several kilometers and lasting up to one hour

Operational status of apex and characteristics of the apex open science data set

The APEX system is fully operational since 2011 and ready to provide well-calibrated data as standard processing output of the APEX PAF and the VITO CDPC to the user community. We sincerely hope that the freely available APEX Open Science Data Set will assist the community in gaining insights into the huge potential of APEX and help in assessing its applicability to specific domains of spectroscopy research

Infectivity and stability of hepatitis C virus in different perfusion solutions

Background: Owing to organ shortage, transplantation of organs from HCV (hepatitis C virus) viremic donors into HCV negative individuals is getting more and more accepted. However, transmission of HCV to the host is nearly universal. Until now it is unknown if preservation solutions (PS) might alter infectivity and stability of HCV in the transplant setting. Therefore, seven different preservation solutions (PS) with variable composition were tested in vitro for their direct anti- and proviral effects on HCV. Methods: In vitro grown HCV based on the JFH-1 isolate was used to characterize the effect of seven different PS on the HCV replication cycle including HCV attachment, entry, replication, and assembly. In addition, HCV stability in PS was tested. Results: Overall, 6/7 PS enhanced HCV infectivity: IGL-1 increased HCV attachment and entry, UW Belzer and Perfadex boosted HCV entry. Production of novel viral particles was enhanced in HTK, UW Belzer, and IGL-1. In contrast, viral replication was significantly reduced in HTK solution while all other PS had no effect on HCV RNA replication. HCV was significantly more stable in HTK solution. Euro Collins was the only PS that did not support HCV infectivity in cell culture. None of the used PS showed cytotoxic effects. Conclusion: Our data indicate that HCV infectivity and stability is maintained by several PS

Methylene Blue Treatment of Grafts During Cold Ischemia Time Reduces the Risk of Hepatitis C Virus Transmission.

Background: Although organ shortage is a rising problem, organs from hepatitis C virus (HCV) ribonucleic acid (RNA)-positive donors are not routinely transplanted in HCV-negative individuals. Because HCV only infects hepatocytes, other organs such as kidneys are merely contaminated with HCV via the blood. In this study, we established a protocol to reduce HCV virions during the cold ischemic time. Methods: Standard virological assays were used to investigate the effect of antivirals, including methylene blue (MB), in different preservation solutions. Kidneys from mini pigs were contaminated with Jc1 or HCV RNA-positive human serum. Afterwards, organs were flushed with MB. Hypothermic machine perfusion was used to optimize reduction of HCV. Results: Three different antivirals were investigated for their ability to inactivate HCV in vitro. Only MB completely inactivated HCV in the presence of all perfusion solutions. Hepatitis C virus-contaminated kidneys from mini pigs were treated with MB and hypothermic machine perfusion without any negative effect on the graft. Human liver-uPA-SCID mice did not establish HCV infection after inoculation with flow through from these kidneys. Conclusions: This proof-of-concept study is a first step to reduce transmission of infectious HCV particles in the transplant setting and might serve as a model for other relevant pathogens