76 research outputs found
Video-driven Neural Physically-based Facial Asset for Production
Production-level workflows for producing convincing 3D dynamic human faces
have long relied on an assortment of labor-intensive tools for geometry and
texture generation, motion capture and rigging, and expression synthesis.
Recent neural approaches automate individual components but the corresponding
latent representations cannot provide artists with explicit controls as in
conventional tools. In this paper, we present a new learning-based,
video-driven approach for generating dynamic facial geometries with
high-quality physically-based assets. For data collection, we construct a
hybrid multiview-photometric capture stage, coupling with ultra-fast video
cameras to obtain raw 3D facial assets. We then set out to model the facial
expression, geometry and physically-based textures using separate VAEs where we
impose a global MLP based expression mapping across the latent spaces of
respective networks, to preserve characteristics across respective attributes.
We also model the delta information as wrinkle maps for the physically-based
textures, achieving high-quality 4K dynamic textures. We demonstrate our
approach in high-fidelity performer-specific facial capture and cross-identity
facial motion retargeting. In addition, our multi-VAE-based neural asset, along
with the fast adaptation schemes, can also be deployed to handle in-the-wild
videos. Besides, we motivate the utility of our explicit facial disentangling
strategy by providing various promising physically-based editing results with
high realism. Comprehensive experiments show that our technique provides higher
accuracy and visual fidelity than previous video-driven facial reconstruction
and animation methods.Comment: For project page, see https://sites.google.com/view/npfa/ Notice: You
may not copy, reproduce, distribute, publish, display, perform, modify,
create derivative works, transmit, or in any way exploit any such content,
nor may you distribute any part of this content over any network, including a
local area network, sell or offer it for sale, or use such content to
construct any kind of databas
Mapping the 2021 October Flood Event in the Subsiding Taiyuan Basin By Multi-Temporal SAR Data
A flood event induced by heavy rainfall hit the Taiyuan basin in north China in early October of 2021. In this study, we map the flood event process using the multi-temporal synthetic aperture radar (SAR) images acquired by Sentinel-1. First, we develop a spatiotemporal filter based on low-rank tensor approximation (STF-LRTA) for removing the speckle noise in SAR images. Next, we employ the classic log-ratio change indicator and the minimum error threshold algorithm to characterize the flood using the filtered images. Finally, we relate the flood inundation to the land subsidence in the Taiyuan basin by jointly analyzing the multi-temporal SAR change detection results and interferometric SAR (InSAR) time-series measurements (pre-flood). The validation experiments compare the proposed filter with the Refined-Lee filter, Gamma filter, and an SHPS-based multi-temporal SAR filter. The results demonstrate the effectiveness and advantage of the proposed STF-LRTA method in SAR despeckling and detail preservation, and the applicability to change scenes. The joint analyses reveal that land subsidence might be an important contributor to the flood event, and the flood recession process linearly correlates with time and subsidence magnitude.This work was financially supported by the National Natural Science Foundation of China (grant numbers 41904001 and 41774006), the China Postdoctoral Science Foundation (grant number 2018M640733), the National Key Research and Development Program of China (grant number 2019YFC1509201), and the National Postdoctoral Program for Innovative Talents (grant number BX20180220)
SCULPTOR: Skeleton-Consistent Face Creation Using a Learned Parametric Generator
Recent years have seen growing interest in 3D human faces modelling due to
its wide applications in digital human, character generation and animation.
Existing approaches overwhelmingly emphasized on modeling the exterior shapes,
textures and skin properties of faces, ignoring the inherent correlation
between inner skeletal structures and appearance. In this paper, we present
SCULPTOR, 3D face creations with Skeleton Consistency Using a Learned
Parametric facial generaTOR, aiming to facilitate easy creation of both
anatomically correct and visually convincing face models via a hybrid
parametric-physical representation. At the core of SCULPTOR is LUCY, the first
large-scale shape-skeleton face dataset in collaboration with plastic surgeons.
Named after the fossils of one of the oldest known human ancestors, our LUCY
dataset contains high-quality Computed Tomography (CT) scans of the complete
human head before and after orthognathic surgeries, critical for evaluating
surgery results. LUCY consists of 144 scans of 72 subjects (31 male and 41
female) where each subject has two CT scans taken pre- and post-orthognathic
operations. Based on our LUCY dataset, we learn a novel skeleton consistent
parametric facial generator, SCULPTOR, which can create the unique and nuanced
facial features that help define a character and at the same time maintain
physiological soundness. Our SCULPTOR jointly models the skull, face geometry
and face appearance under a unified data-driven framework, by separating the
depiction of a 3D face into shape blend shape, pose blend shape and facial
expression blend shape. SCULPTOR preserves both anatomic correctness and visual
realism in facial generation tasks compared with existing methods. Finally, we
showcase the robustness and effectiveness of SCULPTOR in various fancy
applications unseen before.Comment: 16 page, 13 fig
Relightable Neural Human Assets from Multi-view Gradient Illuminations
Human modeling and relighting are two fundamental problems in computer vision
and graphics, where high-quality datasets can largely facilitate related
research. However, most existing human datasets only provide multi-view human
images captured under the same illumination. Although valuable for modeling
tasks, they are not readily used in relighting problems. To promote research in
both fields, in this paper, we present UltraStage, a new 3D human dataset that
contains more than 2,000 high-quality human assets captured under both
multi-view and multi-illumination settings. Specifically, for each example, we
provide 32 surrounding views illuminated with one white light and two gradient
illuminations. In addition to regular multi-view images, gradient illuminations
help recover detailed surface normal and spatially-varying material maps,
enabling various relighting applications. Inspired by recent advances in neural
representation, we further interpret each example into a neural human asset
which allows novel view synthesis under arbitrary lighting conditions. We show
our neural human assets can achieve extremely high capture performance and are
capable of representing fine details such as facial wrinkles and cloth folds.
We also validate UltraStage in single image relighting tasks, training neural
networks with virtual relighted data from neural assets and demonstrating
realistic rendering improvements over prior arts. UltraStage will be publicly
available to the community to stimulate significant future developments in
various human modeling and rendering tasks. The dataset is available at
https://miaoing.github.io/RNHA.Comment: Project page: https://miaoing.github.io/RNH
Dynamic twisting and imaging of moir\'e crystals
The electronic band structure is an intrinsic property of solid-state
materials that is intimately connected to the crystalline arrangement of atoms.
Moir\'e crystals, which emerge in twisted stacks of atomic layers, feature a
band structure that can be continuously tuned by changing the twist angle
between adjacent layers. This class of artificial materials blends the discrete
nature of the moir\'e superlattice with intrinsic symmetries of the constituent
materials, providing a versatile platform for investigation of correlated
phenomena whose origins are rooted in the geometry of the superlattice, from
insulating states at "magic angles" to flat bands in quasicrystals. Here we
present a route to mechanically tune the twist angle of individual atomic
layers with a precision of a fraction of a degree inside a scanning probe
microscope, which enables continuous control of the electronic band structure
in-situ. Using nanostructured rotor devices, we achieve the collective rotation
of a single layer of atoms with minimal deformation of the crystalline lattice.
In twisted bilayer graphene, we demonstrate nanoscale control of the moir\'e
superlattice period via external rotations, as revealed using piezoresponse
force microscopy. We also extend this methodology to create twistable boron
nitride devices, which could enable dynamic control of the domain structure of
moir\'e ferroelectrics. This approach provides a route for real-time
manipulation of moir\'e materials, allowing for systematic exploration of the
phase diagrams at multiple twist angles in a single device
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CR Cistrome: a ChIP-Seq database for chromatin regulators and histone modification linkages in human and mouse
Diversified histone modifications (HMs) are essential epigenetic features. They play important roles in fundamental biological processes including transcription, DNA repair and DNA replication. Chromatin regulators (CRs), which are indispensable in epigenetics, can mediate HMs to adjust chromatin structures and functions. With the development of ChIP-Seq technology, there is an opportunity to study CR and HM profiles at the whole-genome scale. However, no specific resource for the integration of CR ChIP-Seq data or CR-HM ChIP-Seq linkage pairs is currently available. Therefore, we constructed the CR Cistrome database, available online at http://compbio.tongji.edu.cn/cr and http://cistrome.org/cr/, to further elucidate CR functions and CR-HM linkages. Within this database, we collected all publicly available ChIP-Seq data on CRs in human and mouse and categorized the data into four cohorts: the reader, writer, eraser and remodeler cohorts, together with curated introductions and ChIP-Seq data analysis results. For the HM readers, writers and erasers, we provided further ChIP-Seq analysis data for the targeted HMs and schematized the relationships between them. We believe CR Cistrome is a valuable resource for the epigenetics community
Engineering a mevalonate pathway in Halomonas bluephagenesis for the production of lycopene
IntroductionRed-colored lycopene has received remarkable attention in medicine because of its antioxidant properties for reducing the risks of many human cancers. However, the extraction of lycopene from natural hosts is limited. Moreover, the chemically synthesized lycopene raises safety concerns due to residual chemical reagents. Halomonas bluephagenesis is a versatile chassis for the production of fine chemicals because of its open growth property without sterilization.MethodsA heterologous mevalonate (MVA) pathway was introduced into H. bluephagenesis strain TD1.0 to engineer a bacterial host for lycopene production. A pTer7 plasmid mediating the expression of six MVA pathway genes under the control of a phage PMmp1 and an Escherichia coli Ptrc promoters and a pTer3 plasmid providing lycopene biosynthesis downstream genes derived from Streptomyces avermitilis were constructed and transformed into TD1.0. The production of lycopene in the engineered H. bluephagenesis was evaluated. Optimization of engineered bacteria was performed to increase lycopene yield.ResultsThe engineered TD1.0/pTer7-pTer3 produced lycopene at a maximum yield of 0.20 mg/g dried cell weight (DCW). Replacing downstream genes with those from S. lividans elevated the lycopene production to 0.70 mg/g DCW in the TD1.0/pTer7-pTer5 strain. Optimizing the PMmp1 promoter in plasmid pTer7 with a relatively weak Ptrc even increased the lycopene production to 1.22 mg/g DCW. However, the change in the Ptrc promoter in pTer7 with PMmp1 did not improve the yield of lycopene.ConclusionWe first engineered an H. bluephagenesis for the lycopene production. The co-optimization of downstream genes and promoters governing MVA pathway gene expressions can synergistically enhance the microbial overproduction of lycopene
SY18ΔL60L: a new recombinant live attenuated African swine fever virus with protection against homologous challenge
IntroductionAfrican swine fever (ASF) is an acute and highly contagious disease and its pathogen, the African swine fever virus (ASFV), threatens the global pig industry. At present, management of ASF epidemic mainly relies on biological prevention and control methods. Moreover, due to the large genome of ASFV, only half of its genes have been characterized in terms of function.MethodsHere, we evaluated a previously uncharacterized viral gene, L60L. To assess the function of this gene, we constructed a deletion strain (SY18ΔL60L) by knocking out the L60L gene of the SY18 strain. To evaluate the growth characteristics and safety of the SY18ΔL60L, experiments were conducted on primary macrophages and pigs, respectively.ResultsThe results revealed that the growth trend of the recombinant strain was slower than that of the parent strain in vitro. Additionally, 3/5 (60%) pigs intramuscularly immunized with a 105 50% tissue culture infectious dose (TCID50) of SY18ΔL60L survived the 21-day observation period. The surviving pigs were able to protect against the homologous lethal strain SY18 and survive. Importantly, there were no obvious clinical symptoms or viremia.DiscussionThese results suggest that L60L could serve as a virulence- and replication-related gene. Moreover, the SY18ΔL60L strain represents a new recombinant live-attenuated ASFV that can be employed in the development of additional candidate vaccine strains and in the elucidation of the mechanisms associated with ASF infection
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