scholarly journals Fundamental Matrix Computing Based on 3D Metrical Distance

Algorithms ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 89
Author(s):  
Xinsheng Li ◽  
Xuedong Yuan
Keyword(s):  
3D Reconstruction ◽  
Metric Space ◽  
Fundamental Matrix ◽  
Optimization Criterion ◽  
Geometric Distance ◽  
Multiple Images ◽  
Numerical Result ◽  
Projection Error ◽  
New Criterion

To reconstruct point geometry from multiple images, computation of the fundamental matrix is always necessary. With a new optimization criterion, i.e., the re-projective 3D metric geometric distance rather than projective space under RANSAC (Random Sample And Consensus) framework, our method can reveal the quality of the fundamental matrix visually through 3D reconstruction. The geometric distance is the projection error of 3D points to the corresponding image pixel coordinates in metric space. The reasonable visual figures of the reconstructed scenes are shown but only some numerical result were compared, as is standard practice. This criterion can lead to a better 3D reconstruction result especially in 3D metric space. Our experiments validate our new error criterion and the quality of fundamental matrix under the new criterion.

scholarly journals Robust Detection of Point Correspondences in Stereo Images

10.14311/956 ◽  
2007 ◽  
Vol 47 (4-5) ◽  
Author(s):  
A. Stojanovic ◽  
M. Unger
Keyword(s):  
3D Reconstruction ◽  
Fundamental Matrix ◽  
Probabilistic Approach ◽  
Geometric Constraint ◽  
Stereo Images ◽  
Automatic Computation ◽  
Robust Detection ◽  
Image Pairs ◽  
New Criterion

A major challenge in 3D reconstruction is the computation of the fundamental matrix. Automatic computation from uncalibrated image pairs is performed from point correspondences. Due to imprecision and wrong correspondences, only an approximation of the true fundamental matrix can be computed. The quality of the fundamental matrix strongly depends on the location and number of point correspondences.Furthermore, the fundamental matrix is the only geometric constraint between two uncalibrated views, and hence it can be used for the detection of wrong point correspondences. This property is used by current algorithms like RANSAC, which computes the fundamental matrix from a restricted set of point correspondences. In most cases, not only wrong correspondences are disregarded, but also correct ones, which is due to the criterion used to eliminate outliers. In this context, a new criterion preserving a maximum of correct correspondences would be useful.In this paper we introduce a novel criterion for outlier elimination based on a probabilistic approach. The enhanced set of correspondences may be important for further computation towards a 3D reconstruction of the scene. 

scholarly journals Quantification Method for the Uncertainty of Matching Point Distribution on 3D Reconstruction

2020 ◽  
Vol 9 (4) ◽  
pp. 187
Author(s):  
Yuxia Bian ◽  
Xuejun Liu ◽  
Meizhen Wang ◽  
Hongji Liu ◽  
Shuhong Fang ◽  
...  
Keyword(s):  
3D Reconstruction ◽  
Point Cloud ◽  
Point Distribution ◽  
Multiple Images ◽  
Quantification Method ◽  
Real Scene ◽  
Direct Data ◽  
The Relationship ◽  
Overlapping Region

Matching points are the direct data sources of the fundamental matrix, camera parameters, and point cloud calculation. Thus, their uncertainty has a direct influence on the quality of image-based 3D reconstruction and is dependent on the number, accuracy, and distribution of the matching points. This study mainly focuses on the uncertainty of matching point distribution. First, horizontal dilution of precision (HDOP) is used to quantify the feature point distribution in the overlapping region of multiple images. Then, the quantization method is constructed. H D O P ∗ ¯ , the average of 2 × arctan ( H D O P × n 5 − 1 ) / π on all images, is utilized to measure the uncertainty of matching point distribution on 3D reconstruction. Finally, simulated and real scene experiments were performed to describe and verify the rationality of the proposed method. We found that the relationship between H D O P ∗ ¯ and the matching point distribution in this study was consistent with that between matching point distribution and 3D reconstruction. Consequently, it may be a feasible method to predict the quality of 3D reconstruction by calculating the uncertainty of matching point distribution.

scholarly journals Combinatorial clustering and Its Application to 3D Polygonal Traffic Sign Reconstruction From Multiple Images

2014 ◽  
Vol II-3 ◽  
pp. 165-172 ◽  
Author(s):  
B. Vallet ◽  
B. Soheilian ◽  
M. Brédif
Keyword(s):  
Combinatorial Optimization ◽  
3D Reconstruction ◽  
Optimization Problem ◽  
Combinatorial Optimization Problem ◽  
Traffic Sign ◽  
Multiple Images ◽  
3D Objects ◽  
Geometric Quality ◽  
The Individual

The 3D reconstruction of similar 3D objects detected in 2D faces a major issue when it comes to grouping the 2D detections into clusters to be used to reconstruct the individual 3D objects. Simple clustering heuristics fail as soon as similar objects are close. This paper formulates a framework to use the geometric quality of the reconstruction as a hint to do a proper clustering. We present a methodology to solve the resulting combinatorial optimization problem with some simplifications and approximations in order to make it tractable. The proposed method is applied to the reconstruction of 3D traffic signs from their 2D detections to demonstrate its capacity to solve ambiguities.

scholarly journals A 3D Reconstruction Framework of Buildings Using Single Off-Nadir Satellite Image

2021 ◽  
Vol 13 (21) ◽  
pp. 4434
Author(s):  
Chunhui Zhao ◽  
Chi Zhang ◽  
Yiming Yan ◽  
Nan Su
Keyword(s):  
Remote Sensing ◽  
3D Reconstruction ◽  
Spatial Resolution ◽  
Satellite Image ◽  
Geometric Constraints ◽  
Single Image ◽  
Multiple Images ◽  
Angle Size ◽  
Reconstruction Methods ◽  
Mesh Models

A novel framework for 3D reconstruction of buildings based on a single off-nadir satellite image is proposed in this paper. Compared with the traditional methods of reconstruction using multiple images in remote sensing, recovering 3D information that utilizes the single image can reduce the demands of reconstruction tasks from the perspective of input data. It solves the problem that multiple images suitable for traditional reconstruction methods cannot be acquired in some regions, where remote sensing resources are scarce. However, it is difficult to reconstruct a 3D model containing a complete shape and accurate scale from a single image. The geometric constraints are not sufficient as the view-angle, size of buildings, and spatial resolution of images are different among remote sensing images. To solve this problem, the reconstruction framework proposed consists of two convolutional neural networks: Scale-Occupancy-Network (Scale-ONet) and model scale optimization network (Optim-Net). Through reconstruction using the single off-nadir satellite image, Scale-Onet can generate water-tight mesh models with the exact shape and rough scale of buildings. Meanwhile, the Optim-Net can reduce the error of scale for these mesh models. Finally, the complete reconstructed scene is recovered by Model-Image matching. Profiting from well-designed networks, our framework has good robustness for different input images, with different view-angle, size of buildings, and spatial resolution. Experimental results show that an ideal reconstruction accuracy can be obtained both on the model shape and scale of buildings.

scholarly journals Analysis of the job shop system with transport and setup times in deadlock-free operating conditions

2012 ◽  
Vol 22 (4) ◽  
pp. 417-425 ◽  
Author(s):  
Jolanta Krystek ◽  
Marek Kozik
Keyword(s):  
Comparative Research ◽  
Completion Time ◽  
Job Shop ◽  
Optimization Criterion ◽  
Operating Conditions ◽  
Setup Times ◽  
Automated Guided Vehicles ◽  
Transport Time ◽  
Priority Algorithms

This paper presents a generalized job-shop problem taking into consideration transport time between workstations and setups machines in deadlock-free operating conditions. The automated transportation system, employing a number of automated guided vehicles is considered. The completion time of all jobs was applied as the optimization criterion. The created computational application was used to solve this problem in which chosen priority algorithms (FIFO, LIFO, LPT, SPT, EDD and LWR) were implemented. Various criteria were used to assess the quality of created schedules. Numerical results of the comparative research were presented for various criteria and rules of the priority

MODEL OF ASSORTMENT OPTIMIZATION AND INVENTORY MANAGEMENT IN ENTERPRISE

2021 ◽  
Vol 9 (1) ◽  
pp. 31-46
Author(s):  
Ibrokhim Xabibullayev ◽  
◽  
Ruslana Zhovnovach ◽  
Mariia Petrova ◽  
◽  
...  
Keyword(s):  
Inventory Management ◽  
Coefficient Of Variation ◽  
Methodological Approach ◽  
Integrated Approach ◽  
Optimization Criterion ◽  
Commercial Activity ◽  
Commercial Activities ◽  
Individual Product ◽  
Assortment Optimization

The actual problems of work in the sphere of organization of supply and sale are considered, the existing developments in the sphere of modeling and optimization of commercial activity of the wholesale trading enterprises are analyzed. The necessity of a comprehensive approach to improving the commercial activities of wholesalers is substantiated. The composition of the solutions included in the integrated approach is determined by the sole purpose, practical possibilities of its implementation and implementation at the wholesale enterprises and is based on the analysis of actual problems of the industry as a whole, interdependence in the work of departments, development of a single optimization criterion. The effectiveness of the integrated approach is based on the fact that for the sake of maximum result it is important not to isolate the development of individual operations, but to improve the entire purchasing system of the wholesale enterprise as a whole. The scientific and methodological approach of carrying out the integrated ABC-XYZ analysis of a range of a trading enterprise by its combination with R/S analysis, which acts as a criterion for the effectiveness of the XYZ analysis and an indicator of the possibility of forecasting the dynamics of sales of individual product groups, has been improved. XYZ analysis, based on the calculation of the coefficient of variation, when there are deterministic factors such as seasonality, cyclicality or trend in a series of determinants, shows erroneous results. Therefore, it is suggested to use R/S analysis to evaluate the quality of the XYZ analysis and to pre-process the data. This will allow us to draw more adequate conclusions about the possibility of forecasting the dynamics of sales of certain product groups in the future.

Approximation Par des Fonctions Lipschitziennes et Critere de Convergence Etroite D'une Suite de Probabilites

1984 ◽  
Vol 27 (4) ◽  
pp. 514-516 ◽  
Author(s):  
I. Rihaoui
Keyword(s):  
Weak Convergence ◽  
Metric Space ◽  
Bounded Function ◽  
Uniform Limit ◽  
Bounded Functions ◽  
New Criterion ◽  
Uniformly Continuous

AbstractIn this paper, we prove that a real valued bounded function, defined on a metric space and uniformly continuous is the uniform limit of a sequence of Lipschitzian bounded functions.As a consequence, a new criterion for the weak convergence of probabilities is given.

An Experimental Evaluation of the Effects of Filtercake in Wellbore Strengthening: Filtercake Rupture Resistance and Fracture Sealing Time

2019 ◽  
Vol 142 (4) ◽  
Author(s):  
Mingzheng Yang ◽  
Yuanhang Chen
Keyword(s):  
Drilling Fluid ◽  
Experimental Tests ◽  
Fracture Initiation ◽  
Vital Role ◽  
Fracture Sealing ◽  
Initiation Stage ◽  
Induced Fractures ◽  
Wellbore Strengthening ◽  
New Criterion

Abstract Recent research studies have indicated that filtercakes play a role in preventing fracture initiation, blocking pre-existing narrow fractures, and isolating drilling-induced fractures at the initiation stage. The ability of the filtercakes to effectively strengthen the wellbore expectedly depends on its capability in maintaining its integrity and providing the barrier to isolate pressure and fluid transmission between the wellbore and fractures. In this research, a modified permeability apparatus was used to evaluate the quality of drilling fluid filtercakes. A new criterion defined as filtercake rupture resistance is proposed to characterize the filtercake quality regarding its ability to sustain pressure over an open fracture. Experimental tests were conducted to investigate how filtercake thickness and filtercake yield strength affect the rupture resistance. The mechanism of filtercake in sealing the narrow fractures is explored, and it was observed that solid's plugging/bridging plays the vital role in this mechanism. A thicker and stronger filtercake also contributes to a faster establishment of complete fracture seal. The results of this research can be utilized as a reference that guides the optimization of drilling fluid for continuously strengthening the wellbore.

scholarly journals Controlling the Flight of a Drone and Its Camera for 3D Reconstruction of Large Objects

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2333 ◽  
Author(s):  
Simone Mentasti ◽  
Federico Pedersini
Keyword(s):  
3D Reconstruction ◽  
Real Time ◽  
3D Model ◽  
Image Sequence ◽  
Scene Reconstruction ◽  
Entire Process ◽  
Reconstruction Software ◽  
Different Shapes ◽  
User Intervention

In this paper we present a simple stand-alone system performing the autonomous acquisition of multiple pictures all around large objects, i.e., objects that are too big to be photographed from any side just with a camera held by hand. In this approach, a camera carried by a drone (an off-the-shelf quadcopter) is employed to carry out the acquisition of an image sequence representing a valid dataset for the 3D reconstruction of the captured scene. Both the drone flight and the choice of the viewpoints for shooting a picture are automatically controlled by the developed application, which runs on a tablet wirelessly connected to the drone, and controls the entire process in real time. The system and the acquisition workflow have been conceived with the aim to keep the user intervention minimal and as simple as possible, requiring no particular skill to the user. The system has been experimentally tested on several subjects of different shapes and sizes, showing the ability to follow the requested trajectory with good robustness against any flight perturbations. The collected images are provided to a scene reconstruction software, which generates a 3D model of the acquired subject. The quality of the obtained reconstructions, in terms of accuracy and richness of details, have proved the reliability and efficacy of the proposed system.

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