scholarly journals Resolving motion correspondence for densely moving points

2001 ◽  
Vol 23 (1) ◽  
pp. 54-72 ◽  
Author(s):  
C.J. Veenman ◽  
M.J.T. Reinders ◽  
E. Backer
Keyword(s):  
Moving Points ◽  
Motion Correspondence

FAST PURSUIT OF MOBILE NODES USING TPR TREES

2004 ◽  
Vol 15 (05) ◽  
pp. 753-772
Author(s):  
SAHAR IDWAN ◽  
DINESH P. MEHTA ◽  
MARIO A. LOPEZ
Keyword(s):  
Constant Velocity ◽  
Experimental Results ◽  
Mobile Nodes ◽  
Moving Points

In this paper, we consider a set of mobile nodes, each of which moves with constant velocity. We present algorithms to determine which of these mobile nodes can be captured the soonest by a set of one or more pursuers. We use a time parameterized R-tree (TPR-tree) to index these moving points. We then develop algorithms that operate on the TPR-tree to answer three query variations: (1) a single pursuer that is faster than all of the mobile nodes, (2) a single pursuer that is slower than some of the mobile nodes and (3) multiple pursuers. Experimental results show that our algorithms are simpler and faster than other approaches to solve the problem.

scholarly journals Do barriers influence motion correspondence?

2010 ◽  
Vol 1 (3) ◽  
pp. 166-166 ◽  
Author(s):  
K. Yu ◽  
W. D. Craft
Keyword(s):  
Motion Correspondence

Local-Level and Global-Level Form Characteristics in Apparent-Motion Correspondence

Perception ◽  
1995 ◽  
Vol 24 (11) ◽  
pp. 1233-1245 ◽  
Author(s):  
Terry Palmer ◽  
Ovid J L Tzeng ◽  
Sheng He
Keyword(s):  
Apparent Motion ◽  
Motion Detection ◽  
Local Level ◽  
The Other ◽  
Correspondence Problem ◽  
Global Level ◽  
Global Precedence ◽  
Detection Mechanism ◽  
Motion Display ◽  
Motion Correspondence

This study addressed the ‘correspondence’ problem of apparent-motion (AM) perception in which parts of a scene must be matched with counterparts separated in time and space. Given evidence that AM correspondence can be mediated by two distinct processes—one based on a low-level motion-detection mechanism (the Reichardt process), the other involving the tracking of objects by visual attention (the attention-based process)—the present study explored how these processes interact in the perception of apparent motion between hierarchically structured figures. In three experiments, hierarchical figures were presented in a competition motion display so that, across frames, figures were identical at either the local or the global level. In experiment 1 it was shown that AM occurred between locally identical figures. Furthermore, with the Reichardt AM component eliminated in experiments 3 and 4, no preference was obtained for either level. While evidence from previous studies suggests that form extraction for hierarchically structured figures proceeds from the global to the local level, the present results indicate the irrelevance of such a global precedence in AM correspondence. In addition, it is suggested that Reichardt AM correspondence between local elements constrains attention-based AM correspondence between global figures so that both components move in the same direction. It is argued that this constraining process represents an elegant means of achieving AM correspondence between objects undergoing complex transformations.

scholarly journals Kinematic Design of a Seven-Bar Linkage with Optimized Centrodes for Pure-Rolling Cutting

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Biao Liu ◽  
Yali Ma ◽  
Delun Wang ◽  
Shaoping Bai ◽  
Yangyang Li ◽  
...  
Keyword(s):  
Optimal Solution ◽  
Genetic Optimization ◽  
Dimensional Synthesis ◽  
Cutting Mechanism ◽  
Pure Rolling ◽  
Moving Points ◽  
Novel Method ◽  
Design Requirements ◽  
Genetic Optimization Algorithm ◽  
Peak Value

A novel method for designing a seven-bar linkage based on the optimization of centrodes is presented in this paper. The proposed method is applied to the design of a pure-rolling cutting mechanism, wherein close interrelation between the contacting lines and centrodes of two pure-rolling bodies is formulated and the genetic optimization algorithm is adopted for the dimensional synthesis of the mechanism. The optimization is conducted to minimize the error between mechanism centrodes and the expected trajectories, subject to the design requirements of the opening distance, the maximum amount of overlap error, and peak value of shearing force. An optimal solution is obtained and the analysis results show that the horizontal slipping and standard deviation of the lowest moving points of the upper shear blade have been reduced by 78.0% and 80.1% and the peak value of shear stress decreases by 29%, which indicate better cutting performance and long service life.

Early recognizing of a hurricanes from public satellite images

2021 ◽  
Author(s):  
A.A. Kuzmitsky ◽  
M.I. Truphanov ◽  
O.B. Tarasova ◽  
D.V. Fedosenko
Keyword(s):  
Satellite Images ◽  
A Priori ◽  
Vortex Formation ◽  
Weather Conditions ◽  
Local Area ◽  
Weather Data ◽  
Polar Coordinate System ◽  
Practical Implementation ◽  
Characteristic Points ◽  
Moving Points

One of the key tasks associated with the fast identification of powerful tropical hurricanes, the assessment of the growth of their power, is the formation of such an input dataset, which is based on data that are technically easy and accurately recorded and calculated using existing sources located in the open accessibility. The presented work is based on the analysis of satellite images as the main data sources, and on weather data as peripheral. An obvious advantage of satellite images in comparison with other sources of data on weather conditions is their high spatial resolution, as well as the ability to obtain data from various satellites, which increases the timeliness and accuracy of retrieving primary information. The developed approach consists in performing the following main interconnected iteratively performed groups of subtasks: calculation of feature points describing the location of individual cloud areas at different points in time by using different descriptors; comparison of the same cloud areas at specified times to analyze the local directions of cloud movements; tracking of cloudiness for specified time intervals; calculation of local features for selected points of cloudiness to recognize the origin and analyze turbulence; the formation of the dynamics of changes in the local area near the trajectory of the point; recognition of primary characteristic features characterizing the transformation of local turbulences into a stable vortex formation; identification of signs of the growing of a hurricane and assessment of the primary dynamics of the increase in its power; generalization and refinement of a priori given features by analyzing similar features of known cyclones. To detect points, a modified algorithm for finding them has been introduced. To describe the points, additional descriptors are introduced based on the normalized gradient measured for the neighborhood of neighboring points and cyclically changing in the polar coordinate system. A comparative analysis of the results of applying the created method and algorithm when compared with known similar solutions revealed the following distinctive features: introduction of additional invariant orientations of features when describing characteristic points and greater stability of detecting characteristic points when analyzing cloudiness, identification of cloudiness turbulence and analysis of changes in their local characteristics and movement parameters, formation of a set of generalizing distributions when analyzing a set of moving points for the subsequent recognition of the signs of a hurricane at its initial stages of formation. The developed approach was tested experimentally in the analysis of hurricanes video recordings and their movement in the Atlantic region for the period from 2010 to 2020. The developed general approach and a specific algorithm for estimating hurricane parameters based on cloud analysis are presented. The approach is applicable for practical implementation and allows accumulating data for detecting hurricanes in real time based on publicly available data for the development of a physical and mathematical model.

scholarly journals A Meshless Solution Method for Unsteady Flow with Moving Boundary

2014 ◽  
Vol 6 ◽  
pp. 209575 ◽  
Author(s):  
Jun Zhang ◽  
Deng-feng Ren ◽  
Xin-jian Ma ◽  
Jun-jie Tan ◽  
Xiao-wei Cai
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Meshless Method ◽  
Moving Objects ◽  
Moving Boundary ◽  
Initial Position ◽  
Piston Problem ◽  
Naca0012 Airfoil ◽  
Moving Body ◽  
Moving Points

Using the concept of overlapping mesh method for reference, a new method called as Overlapping Clouds of Points Method (OCPM) is firstly proposed to simulate unsteady flow with moving boundary problems based on meshless method. Firstly, a set of static background discrete points is generated in the whole calculation zone. Secondly, moving discrete points are created around moving body. According to the initial position of moving object in the flow field, the two sets of discrete points can be overlapped. With the motion of moving objects in the calculation field, moving discrete points around the moving body will inherently move. The exchange of flow field information between static points and moving points is realized by the solution of the clouds of points made up of static and moving discrete points using weighted meshless method nearby overlapping boundary. Four cases including piston problem, NACA0012 airfoil vibration flow around a moving sphere in supersonic and multibody separation are given to verify accuracy and practicability of OCPM. The numerical results agree well with exact solution and experimental results, which shows that the proposed OCPM can be applied to the simulation of unsteady flow problem.

Mobility, Orientation, and Navigation: Conceptual and Theoretical Considerations

1976 ◽  
Vol 70 (9) ◽  
pp. 385-391
Author(s):  
George Psathas
Keyword(s):  
Detailed Knowledge ◽  
Directed Movement ◽  
Moving Points ◽  
Theoretical Considerations ◽  
Complex Activities ◽  
Intended Destination ◽  
Person Orientation

Analyzes mobility, orientation, and navigation and describes the complex activities and detailed knowledge required by each. Mobility involves movement of an embodied person; orientation involves knowing where one is, in relation to fixed or moving points; navigation is directed movement with an intended destination and requires knowledge of directions and locations.

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