scholarly journals Velocity field of image points in satellite imagery of planet’s surface

2020 ◽  
Vol 8 (1) ◽  
pp. 97-109
Author(s):  
V. Ya. Gecha ◽  
M. Yu. Zhilenev ◽  
V. B. Fyodorov ◽  
D. A. Khrychev ◽  
Yu. I. Hudak ◽  
...  
Keyword(s):  
Velocity Field ◽  
Angular Velocity ◽  
Satellite Imagery ◽  
Focal Length ◽  
Arbitrary Point ◽  
True Anomaly ◽  
Orbital Parameters ◽  
Imaging Camera ◽  
Image Blurring ◽  
Blurred Image

This paper derives a formula for calculating the velocity of arbitrary point in the field of view of the satellite camera in the process of orbital imagery of the planet's surface. The formula describes the velocity as a function of the point coordinates in the image fixation plane, the focal length of the imaging camera, the orbital parameters of the satellite, the angular velocity of the planet’s rotation, the coordinates of the satellite’s true anomaly in the orbit, the orientation angles of the imaging camera relative to the orbit, and the angular velocity of the camera. The paper also provides examples of the formula use for calculating the velocity field of image points for different sets of imagery parameters.The formula is derived under the assumption that the planet is a homogeneous absolutely solid body, shaped as a ball, and rotating at a constant angular velocity; as a result, the satellite moves in a Keplerian orbit, with the planet located at one of the orbit’s foci. Despite this idealization, the derived formula can be used in developing algorithms for remote sensing of the Earth, for building and optimizing the image blurring compensators, for solving the problem of blurred image recovery, and for a number of other problems related to satellite imagery preparation, execution, and processing the results.

Finite difference code for velocity and surface traction of a Fluid between Two Eccentric Spheres

2015 ◽  
Vol 11 (1) ◽  
pp. 2960-2971
Author(s):  
M.Abdel Wahab
Keyword(s):  
Velocity Field ◽  
Angular Velocity ◽  
Finite Difference ◽  
Numerical Study ◽  
Outer Sphere ◽  
Equation Of Motion ◽  
Annular Region ◽  
Surface Traction ◽  
Angular Velocities ◽  
Axis Passing

The Numerical study of the flow of a fluid in the annular region between two eccentric sphere susing PHP Code isinvestigated. This flow is created by considering the inner sphere to rotate with angular velocity 1  and the outer sphererotate with angular velocity 2  about the axis passing through their centers, the z-axis, using the three dimensionalBispherical coordinates (, ,) .The velocity field of fluid is determined by solving equation of motion using PHP Codeat different cases of angular velocities of inner and outer sphere. Also Finite difference code is used to calculate surfacetractions at outer sphere.

scholarly journals The influence of circulation on the stability of vortices to mode-one disturbances

1995 ◽  
Vol 451 (1943) ◽  
pp. 747-755 ◽  
Keyword(s):  
Velocity Field ◽  
Angular Velocity ◽  
Initial Value Problem ◽  
Large Time ◽  
Asymptotic Methods ◽  
Two Dimensional ◽  
Initial Value ◽  
The Stability ◽  
Ultimate Fate ◽  
Solution Behaviour

The initial value problem for the two-dimensional inviscid vorticity equation, linearized about an azimuthal basic velocity field with monotonic angular velocity, is solved exactly for mode-one disturbances. The solution behaviour is investigated for large time using asymptotic methods. The circulation of the basic state is found to govern the ultimate fate of the disturbance: for basic state vorticity distributions with non-zero circulation, the perturbation tends to the steady solution first mentioned in Michalke & Timme (1967), while for zero circulation, the perturbation grows without bound. The latter case has potentially important implications for the stability of isolated eddies in geophysics.

scholarly journals Investigation level of correlation between orbital parameters model for geometric correction of satellite imagery

2014 ◽  
Vol 2 (3) ◽  
pp. 35-50
Author(s):  
Alireza Safdari Nezhad ◽  
Mohammd Javad Valadan Zoej ◽  
Mehdi Mokhtarzadeh ◽  
◽  
◽  
...  
Keyword(s):  
Satellite Imagery ◽  
Geometric Correction ◽  
Orbital Parameters

The forced flow of a rotating viscous liquid which is heated from below

1953 ◽  
Vol 246 (907) ◽  
pp. 81-112 ◽  
Keyword(s):  
Velocity Field ◽  
Angular Velocity ◽  
Viscous Liquid ◽  
Opposite Direction ◽  
Equations Of Motion ◽  
Cylindrical Vessel ◽  
Central Axis ◽  
Forced Flow ◽  
Outer Portion ◽  
Non Linear

A liquid is contained in a cylindrical vessel and is subject to heating on the horizontal base of the vessel. The problem of the forced flow arising from the heating has been investigated in the case when the heating function is symmetrically arranged about the central axis. It is found that the relative forced flow tends to become zonal in character when the vessel rotates at a sufficiently high angular velocity. This relative zonal motion is principally in the direction of the rotation except near the outer portion of the fluid where it is in the opposite direction, the former being ‘westerlies’, the latter ‘easterlies’. The easterlies are due to the non-linear inertia terms in the equations of motion. This description of the velocity field is used because the experiment described above has considerable meteorological significance.

scholarly journals Joint Image Deblurring and Matching with Blurred Invariant-Based Sparse Representation Prior

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Yuanjie Shao ◽  
Nong Sang ◽  
Juncai Peng ◽  
Changxin Gao
Keyword(s):  
Sparse Representation ◽  
Image Matching ◽  
Image Deblurring ◽  
Image Feature ◽  
Zernike Moment ◽  
Invariant Space ◽  
Pseudo Zernike Moment ◽  
Image Blurring ◽  
Blurred Image

Image matching is important for vision-based navigation. However, most image matching approaches do not consider the degradation of the real world, such as image blur; thus, the performance of image matching often decreases greatly. Recent methods try to deal with this problem by utilizing a two-stage framework—first resorting to image deblurring and then performing image matching, which is effective but depends heavily on the quality of image deblurring. An emerging way to resolve this dilemma is to perform image deblurring and matching jointly, which utilize sparse representation prior to explore the correlation between deblurring and matching. However, these approaches obtain the sparse representation prior in the original pixel space, which do not adequately consider the influence of image blurring and thus may lead to an inaccurate estimation of sparse representation prior. Fortunately, we can extract the pseudo-Zernike moment with blurred invariant from images and obtain a reliable sparse representation prior in the blurred invariant space. Motivated by the observation, we propose a joint image deblurring and matching method with blurred invariant-based sparse representation prior (JDM-BISR), which obtains the sparse representation prior in the robust blurred invariant space rather than the original pixel space and thus can effectively improve the quality of image deblurring and the accuracy of image matching. Moreover, since the dimension of the pseudo-Zernike moment is much lower than the original image feature, our model can also increase the computational efficiency. Extensive experimental results demonstrate that the proposed method performs favorably against the state-of-the-art blurred image matching approach.

Shear layers in a rotating fluid

1967 ◽  
Vol 29 (1) ◽  
pp. 165-175 ◽  
Author(s):  
D. James Baker
Keyword(s):  
Velocity Field ◽  
Angular Velocity ◽  
Shear Layer ◽  
Vertical Velocity ◽  
Vertical Shear ◽  
Geometrical Parameters ◽  
Homogeneous Fluid ◽  
Rotating System ◽  
Layer Flow ◽  
Good Agreement

A homogeneous fluid of viscosityvis confined between two co-axial disks (vertical separationH) which rotate relative to a rotating system (angular velocity Ω). The resulting velocity field is studied for values of the parameterv/2ΩH2in the range 1·6 × 10−2to 1·8 × 10−3. The Rossby number, defined as the ratio of the relative angular velocity of the disks to the angular velocity of the system, ranged from 0·038 to 0·0041. The dependence of the resulting velocity field (interior and boundary-layer flow) on geometrical parameters, imposed surface and bottom velocities, and Ω, is in good agreement with the calculations of Stewartson and Carrier. In particular, when the two disks rotate with the same angular velocity, the width of the vertical shear layer at the edge of the disks is found to be proportional to Ω−0·25±0·02. When the disks rotate in opposite senses, a shear layer in the vertical velocity is observed which transports fluid from one disk to the other and whose width is proportional to Ω−0·40±0·10. The magnitude and shape of the observed vertical velocity is in fair agreement with a numerical integration of the theoretical results.

Study on Flow Field Intensification of Dynamic Pre-Cyclone Separators

2012 ◽  
Vol 550-553 ◽  
pp. 3210-3213
Author(s):  
Jiu Peng Zou ◽  
Feng Xia Liu ◽  
Yu Qiang Dai ◽  
Jin Tao Wu ◽  
Pei Qi Liu ◽  
...  
Keyword(s):  
Velocity Field ◽  
Numerical Model ◽  
Angular Velocity ◽  
Flow Field ◽  
Uniform Flow ◽  
Driving Dynamic ◽  
Novel Structure ◽  
External Driving

Abstract Because of external driving, dynamic pre-cyclone separators have excellent operational performances in areas of pressure vary occasionally. In this work, a numerical model of the dynamic separator been built and the flow field is thoroughly studied. The distribution results of angular velocity show that an appropriate structure of pre-cyclone vanes is of great importance to get a relative uniform flow angular velocity field. A novel structure of pre-cyclone vanes under different separation requirements is developed and verified by a number of experiments.

scholarly journals Haze Removal Based on Refined Transmission Map for Aerial Image Matching

2021 ◽  
Vol 11 (15) ◽  
pp. 6917
Author(s):  
Yogendra Rao Musunuri ◽  
Oh-Seol Kwon
Keyword(s):  
Image Matching ◽  
Aerial Image ◽  
Image Dehazing ◽  
Haze Removal ◽  
Dark Channel ◽  
Image Blurring ◽  
Degraded Image ◽  
Blurred Image ◽  
Novel Strategy ◽  
Local Feature Extraction

A novel strategy is proposed to address block artifacts in a conventional dark channel prior (DCP). The DCP was used to estimate the transmission map based on patch-based processing, which also results in image blurring. To enhance a degraded image, the proposed single-image dehazing technique restores a blurred image with a refined DCP based on a hidden Markov random field. Therefore, the proposed algorithm estimates a refined transmission map that can reduce the block artifacts and improve the image clarity without explicit guided filters. Experiments were performed on the remote-sensing images. The results confirm that the proposed algorithm is superior to the conventional approaches to image haze removal. Moreover, the proposed algorithm is suitable for image matching based on local feature extraction.

A new upper bound solution for a hollow cylinder subjected to compression and twist

2004 ◽  
Vol 218 (4) ◽  
pp. 369-375 ◽  
Author(s):  
S Alexandrov ◽  
G-Y Tzou ◽  
S-Y Hsia
Keyword(s):  
Velocity Field ◽  
Angular Velocity ◽  
Hollow Cylinder ◽  
Upper Bound ◽  
Geometrical Parameters ◽  
Parallel Plates ◽  
Compression Force ◽  
Bound Solution ◽  
Friction Factors ◽  
Upper Bound Technique

The upper bound technique is adopted to investigate the effect of angular velocity on the load required to compress a circular hollow cylinder between rough parallel plates. The kinematically admissible velocity field accounts for the asymptotic behaviour of the actual velocity field in a vicinity of the friction surface. The theoretical solution is illustrated by numerical examples for different geometrical parameters and friction factors. In particular, the variations in work rate, torsion moment and compression force with the dimensionless angular velocity are shown.

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