scholarly journals Key Issues in Modeling of Complex 3D Structures from Video Sequences

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Shengyong Chen ◽  
Yuehui Wang ◽  
Carlo Cattani
Keyword(s):  
Basic Principle ◽  
Video Analysis ◽  
Structure From Motion ◽  
State Of The Art ◽  
Three Dimensional ◽  
Video Sequences ◽  
3D Structures ◽  
Uncalibrated Camera ◽  
Key Issues ◽  
Scene Object

Construction of three-dimensional structures from video sequences has wide applications for intelligent video analysis. This paper summarizes the key issues of the theory and surveys the recent advances in the state of the art. Reconstruction of a scene object from video sequences often takes the basic principle of structure from motion with an uncalibrated camera. This paper lists the typical strategies and summarizes the typical solutions or algorithms for modeling of complex three-dimensional structures. Open difficult problems are also suggested for further study.

scholarly journals Evaluating the Performance of Structure from Motion Pipelines

2018 ◽  
Vol 4 (8) ◽  
pp. 98 ◽  
Author(s):  
Simone Bianco ◽  
Gianluigi Ciocca ◽  
Davide Marelli
Keyword(s):  
Structure From Motion ◽  
State Of The Art ◽  
Three Dimensional ◽  
Synthetic Data ◽  
Ground Truth ◽  
Evaluation Procedure ◽  
Estimation Errors ◽  
Dimensional Reconstruction ◽  
Synthetic Datasets ◽  
Processing Steps

Structure from Motion (SfM) is a pipeline that allows three-dimensional reconstruction starting from a collection of images. A typical SfM pipeline comprises different processing steps each of which tackles a different problem in the reconstruction pipeline. Each step can exploit different algorithms to solve the problem at hand and thus many different SfM pipelines can be built. How to choose the SfM pipeline best suited for a given task is an important question. In this paper we report a comparison of different state-of-the-art SfM pipelines in terms of their ability to reconstruct different scenes. We also propose an evaluation procedure that stresses the SfM pipelines using real dataset acquired with high-end devices as well as realistic synthetic dataset. To this end, we created a plug-in module for the Blender software to support the creation of synthetic datasets and the evaluation of the SfM pipeline. The use of synthetic data allows us to easily have arbitrarily large and diverse datasets with, in theory, infinitely precise ground truth. Our evaluation procedure considers both the reconstruction errors as well as the estimation errors of the camera poses used in the reconstruction.

From Levinthal’s Paradox to the Effects of Cell Environmental Perturbation on Protein Folding

2020 ◽  
Vol 26 (42) ◽  
pp. 7537-7554 ◽  
Author(s):  
Juan Zeng ◽  
Zunnan Huang
Keyword(s):  
Protein Folding ◽  
Posttranslational Modifications ◽  
Three Dimensional ◽  
Rational Drug Design ◽  
Basic Knowledge ◽  
Sequence Evolution ◽  
3D Structures ◽  
Folding Mechanism ◽  
Cellular Environment ◽  
Environment Temperature

Background: The rapidly increasing number of known protein sequences calls for more efficient methods to predict the Three-Dimensional (3D) structures of proteins, thus providing basic knowledge for rational drug design. Understanding the folding mechanism of proteins is valuable for predicting their 3D structures and for designing proteins with new functions and medicinal applications. Levinthal’s paradox is that although the astronomical number of conformations possible even for proteins as small as 100 residues cannot be fully sampled, proteins in nature normally fold into the native state within timescales ranging from microseconds to hours. These conflicting results reveal that there are factors in organisms that can assist in protein folding. Methods: In this paper, we selected a crowded cell-like environment and temperature, and the top three Posttranslational Modifications (PTMs) as examples to show that Levinthal’s paradox does not reflect the folding mechanism of proteins. We then revealed the effects of these factors on protein folding. Results: The results summarized in this review indicate that a crowded cell-like environment, temperature, and the top three PTMs reshape the Free Energy Landscapes (FELs) of proteins, thereby regulating the folding process. The balance between entropy and enthalpy is the key to understanding the effect of the crowded cell-like environment and PTMs on protein folding. In addition, the stability/flexibility of proteins is regulated by temperature. Conclusion: This paper concludes that the cellular environment could directly intervene in protein folding. The long-term interactions of the cellular environment and sequence evolution may enable proteins to fold efficiently. Therefore, to correctly understand the folding mechanism of proteins, the effect of the cellular environment on protein folding should be considered.

scholarly journals Small footprint optoelectrodes using ring resonators for passive light localization

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Vittorino Lanzio ◽  
Gregory Telian ◽  
Alexander Koshelev ◽  
Paolo Micheletti ◽  
Gianni Presti ◽  
...  
Keyword(s):  
State Of The Art ◽  
Three Dimensional ◽  
Network Activity ◽  
Ring Resonators ◽  
Spatiotemporal Resolution ◽  
Optical Ring Resonators ◽  
Light Localization ◽  
Order Of Magnitude ◽  
Small Footprint

AbstractThe combination of electrophysiology and optogenetics enables the exploration of how the brain operates down to a single neuron and its network activity. Neural probes are in vivo invasive devices that integrate sensors and stimulation sites to record and manipulate neuronal activity with high spatiotemporal resolution. State-of-the-art probes are limited by tradeoffs involving their lateral dimension, number of sensors, and ability to access independent stimulation sites. Here, we realize a highly scalable probe that features three-dimensional integration of small-footprint arrays of sensors and nanophotonic circuits to scale the density of sensors per cross-section by one order of magnitude with respect to state-of-the-art devices. For the first time, we overcome the spatial limit of the nanophotonic circuit by coupling only one waveguide to numerous optical ring resonators as passive nanophotonic switches. With this strategy, we achieve accurate on-demand light localization while avoiding spatially demanding bundles of waveguides and demonstrate the feasibility with a proof-of-concept device and its scalability towards high-resolution and low-damage neural optoelectrodes.

scholarly journals A Benchmark and Evaluation of Non-Rigid Structure from Motion

2020 ◽  
Author(s):  
Sebastian Hoppe Nesgaard Jensen ◽  
Mads Emil Brix Doest ◽  
Henrik Aanæs ◽  
Alessio Del Bue
Keyword(s):  
Computer Vision ◽  
Structure From Motion ◽  
State Of The Art ◽  
The State ◽  
Quality Data ◽  
Data Set ◽  
Rigid Structure ◽  
Public Data ◽  
3D Information ◽  
Further Development

AbstractNon-rigid structure from motion (nrsfm), is a long standing and central problem in computer vision and its solution is necessary for obtaining 3D information from multiple images when the scene is dynamic. A main issue regarding the further development of this important computer vision topic, is the lack of high quality data sets. We here address this issue by presenting a data set created for this purpose, which is made publicly available, and considerably larger than the previous state of the art. To validate the applicability of this data set, and provide an investigation into the state of the art of nrsfm, including potential directions forward, we here present a benchmark and a scrupulous evaluation using this data set. This benchmark evaluates 18 different methods with available code that reasonably spans the state of the art in sparse nrsfm. This new public data set and evaluation protocol will provide benchmark tools for further development in this challenging field.

scholarly journals GRAVITY-WAVE DETECTORS AS PROBES OF EXTRA DIMENSIONS

2005 ◽  
Vol 14 (12) ◽  
pp. 2347-2353 ◽  
Author(s):  
CHRIS CLARKSON ◽  
ROY MAARTENS
Keyword(s):  
Black Holes ◽  
String Theory ◽  
Gravity Wave ◽  
Gravity Waves ◽  
Extra Dimensions ◽  
State Of The Art ◽  
Three Dimensional ◽  
Observable Universe ◽  
Dimensional Spacetime ◽  
Higher Dimensional

If string theory is correct, then our observable universe may be a three-dimensional "brane" embedded in a higher-dimensional spacetime. This theoretical scenario should be tested via the state-of-the-art in gravitational experiments — the current and upcoming gravity-wave detectors. Indeed, the existence of extra dimensions leads to oscillations that leave a spectroscopic signature in the gravity-wave signal from black holes. The detectors that have been designed to confirm Einstein's prediction of gravity waves, can in principle also provide tests and constraints on string theory.

Encoding of three-dimensional structure-from-motion by primate area MT neurons

Nature ◽  
10.1038/33688 ◽  
1998 ◽  
Vol 392 (6677) ◽  
pp. 714-717 ◽  
Author(s):  
David C. Bradley ◽  
Grace C. Chang ◽  
Richard A. Andersen
Keyword(s):  
Structure From Motion ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Area Mt ◽  
Three Dimensional Structure ◽  
Mt Neurons

Inferring Structure from Motion in Two-View and Multiview Displays

Perception ◽  
1993 ◽  
Vol 22 (12) ◽  
pp. 1441-1465 ◽  
Author(s):  
Jeffrey C Liter ◽  
Myron L Braunstein ◽  
Donald D Hoffman
Keyword(s):  
Relative Motion ◽  
Apparent Motion ◽  
Structure From Motion ◽  
Three Dimensional ◽  
Rigid Motion ◽  
Parameter Family ◽  
Image Motion ◽  
Heuristic Analysis

Five experiments were conducted to examine constraints used to interpret structure-from-motion displays. Theoretically, two orthographic views of four or more points in rigid motion yield a one-parameter family of rigid three-dimensional (3-D) interpretations. Additional views yield a unique rigid interpretation. Subjects viewed two-view and thirty-view displays of five-point objects in apparent motion. The subjects selected the best 3-D interpretation from a set of 89 compatible alternatives (experiments 1–3) or judged depth directly (experiment 4). In both cases the judged depth increased when relative image motion increased, even when the increased motion was due to increased simulation rotation. Subjects also judged rotation to be greater when either simulated depth or simulated rotation increased (experiment 4). The results are consistent with a heuristic analysis in which perceived depth is determined by relative motion.

Fused filament printing of specialized biomedical devices: a state-of-the art review of technological feasibilities with PEEK

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Erfan Rezvani Ghomi ◽  
Saeideh Kholghi Eshkalak ◽  
Sunpreet Singh ◽  
Amutha Chinnappan ◽  
Seeram Ramakrishna ◽  
...  
Keyword(s):  
High Performance ◽  
State Of The Art ◽  
Three Dimensional ◽  
Patient Specific ◽  
Biomedical Devices ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Patient Specific Implants ◽  
Complex Design ◽  
Wide Range

Purpose The potential implications of the three-dimensional printing (3DP) technology are growing enormously in the various health-care sectors, including surgical planning, manufacturing of patient-specific implants and developing anatomical models. Although a wide range of thermoplastic polymers are available as 3DP feedstock, yet obtaining biocompatible and structurally integrated biomedical devices is still challenging owing to various technical issues. Design/methodology/approach Polyether ether ketone (PEEK) is an organic and biocompatible compound material that is recently being used to fabricate complex design geometries and patient-specific implants through 3DP. However, the thermal and rheological features of PEEK make it difficult to process through the 3DP technologies, for instance, fused filament fabrication. The present review paper presents a state-of-the-art literature review of the 3DP of PEEK for potential biomedical applications. In particular, a special emphasis has been given on the existing technical hurdles and possible technological and processing solutions for improving the printability of PEEK. Findings The reviewed literature highlighted that there exist numerous scientific and technical means which can be adopted for improving the quality features of the 3D-printed PEEK-based biomedical structures. The discussed technological innovations will help the 3DP system to enhance the layer adhesion strength, structural stability, as well as enable the printing of high-performance thermoplastics. Originality/value The content of the present manuscript will motivate young scholars and senior scientists to work in exploring high-performance thermoplastics for 3DP applications.

Hydrogel-Based Bioinks for Three-Dimensional Bioprinting: Patent Analysis

2021 ◽  
Vol 7 (1) ◽  
pp. 3
Author(s):  
Ahmed Fatimi
Keyword(s):  
Tissue Engineering ◽  
Detailed Analysis ◽  
State Of The Art ◽  
Three Dimensional ◽  
Patent Analysis ◽  
The State ◽  
Driving Factors ◽  
3D Bioprinting ◽  
Preparation Methods

There are a variety of hydrogel-based bioinks commonly used in three-dimensional bioprinting. In this study, in the form of patent analysis, the state of the art has been reviewed by introducing what has been patented in relation to hydrogel-based bioinks. Furthermore, a detailed analysis of the patentability of the used hydrogels, their preparation methods and their formulations, as well as the 3D bioprinting process using hydrogels, have been provided by determining publication years, jurisdictions, inventors, applicants, owners, and classifications. The classification of patents reveals that most inventions intended for hydrogels used as materials for prostheses or for coating prostheses are characterized by their function or properties Knowledge clusters and expert driving factors show that biomaterials, tissue engineering, and biofabrication research is concentrated in the most patents.

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