Accurate Small Deformation Exponential Approximant to Integrate Large Velocity Fields: Application to Image Registration

2016 ◽  
Author(s):  
Sebastiano Ferraris ◽  
Marco Lorenzi ◽  
Pankaj Daga ◽  
Marc Modat ◽  
Tom Vercauteren
Keyword(s):  
Image Registration ◽  
Small Deformation ◽  
Velocity Fields ◽  
Large Velocity

Image registration using stationary velocity fields parameterized by norm-minimizing Wendland kernel

2015 ◽  
Author(s):  
Akshay Pai ◽  
Stefan Sommer ◽  
Lauge Sørensen ◽  
Sune Darkner ◽  
Jon Sporring ◽  
...  
Keyword(s):  
Image Registration ◽  
Velocity Fields ◽  
Stationary Velocity

scholarly journals PIV with volume lighting in a narrow cell: An efficient method to measure large velocity fields of rapidly varying flows

2011 ◽  
Vol 35 (6) ◽  
pp. 1030-1037 ◽  
Author(s):  
Matthieu Roudet ◽  
Anne-Marie Billet ◽  
Frédéric Risso ◽  
Véronique Roig
Keyword(s):  
Efficient Method ◽  
Velocity Fields ◽  
Large Velocity ◽  
Narrow Cell

Kernel Bundle Diffeomorphic Image Registration Using Stationary Velocity Fields and Wendland Basis Functions

2016 ◽  
Vol 35 (6) ◽  
pp. 1369-1380 ◽  
Author(s):  
Akshay Pai ◽  
Stefan Sommer ◽  
Lauge Sorensen ◽  
Sune Darkner ◽  
Jon Sporring ◽  
...  
Keyword(s):  
Image Registration ◽  
Velocity Fields ◽  
Basis Functions ◽  
Diffeomorphic Image Registration ◽  
Stationary Velocity

scholarly journals High resolution nonlinear registration with simultaneous modelling of intensities

2019 ◽  
Author(s):  
Jesper L. R. Andersson ◽  
Mark Jenkinson ◽  
Stephen Smith
Keyword(s):  
Experimental Data ◽  
High Resolution ◽  
Image Registration ◽  
Cost Function ◽  
Small Deformation ◽  
Brain Regions ◽  
Software Library ◽  
Joint Shape ◽  
Nonlinear Registration ◽  
Intensity Model

AbstractThis paper describes and evaluates FMRIB’s nonlinear image registration tool (FNIRT), that is part of the FMRIB software library (FSL). It is a small deformation framework using sum of squared differences (SSD) as its cost function and Gauss-Newton for minimisation. The framework uses a joint shape and intensity model that attempts to explain the observed differences between two images in terms of having different shape and/or contrast, being differently affected by intensity bias-fields etc. Thus the estimation of the warps will be relatively unaffected by intensity differences that would otherwise violate the assumptions behind the SSD cost function. It uses a projection onto a manifold defined by a specified range of allowed Jacobian determinants to ensure that the warps are diffeomorphic. The utility of the model is demonstrated on a variety of simulated and experimental data with good results. FNIRT is also quantitatively evaluated using previously published datasets consisting of scans from multiple subjects, all with anatomically defined brain regions that are manually outlined. In this evaluation FNIRT performs well in comparison to previously published results with other registration algorithms.

Improved Image Registration Technique Using Demons and B-Spline

2013 ◽  
Author(s):  
Chao Tang ◽  
Xiaohui Xie ◽  
Ruxu Du
Keyword(s):  
Image Registration ◽  
Large Deformation ◽  
Small Deformation ◽  
New Method ◽  
Free Form ◽  
Spline Method ◽  
Deformation Method ◽  
B Spline ◽  
Demons Algorithm ◽  
Better Than

Non-rigid image registration is an important and challenge work in image processing. The demons algorithm is one of the most effective non-rigid image registration methods. However, it is only suitable for images with small deformation. In recent years, many improving techniques are proposed. The free form deformation method based on B-spline function is widely employed in non-rigid image registration and is good at dealing with large deformation image registration. However, the performance of the demons algorithm is better than that of the B-spline method in dealing with small deformation registration. Therefore, in this paper, we propose to combine the demons algorithm and the B-spline method. The new method consists of two steps: First, it applies the B-spline method to deal with the large deformation. Then, it uses the demons algorithm to treat the small deformation. The testing results show that the new method is effective in dealing images with both small and large deformations. Comparing to the demons algorithm as well as the B-spline method, the new method has the smallest registration error and hence, is the best.

C. The Continuous Spectrum of Pulsating Variable Stars

1967 ◽  
Vol 28 ◽  
pp. 177-206
Author(s):  
J. B. Oke ◽  
C. A. Whitney
Keyword(s):  
Continuous Spectrum ◽  
Variable Stars ◽  
Velocity Fields ◽  
The Other ◽  
Line Spectrum ◽  
Direct Information ◽  
Thermodynamic Structure ◽  
Diagnostic Interpretation ◽  
Pulsating Variable Stars ◽  
The Continuum

Pecker:The topic to be considered today is the continuous spectrum of certain stars, whose variability we attribute to a pulsation of some part of their structure. Obviously, this continuous spectrum provides a test of the pulsation theory to the extent that the continuum is completely and accurately observed and that we can analyse it to infer the structure of the star producing it. The continuum is one of the two possible spectral observations; the other is the line spectrum. It is obvious that from studies of the continuum alone, we obtain no direct information on the velocity fields in the star. We obtain information only on the thermodynamic structure of the photospheric layers of these stars–the photospheric layers being defined as those from which the observed continuum directly arises. So the problems arising in a study of the continuum are of two general kinds: completeness of observation, and adequacy of diagnostic interpretation. I will make a few comments on these, then turn the meeting over to Oke and Whitney.

The Interpretation of Line Profiles

1977 ◽  
Vol 36 ◽  
pp. 191-215
Author(s):  
G.B. Rybicki
Keyword(s):  
Magnetic Fields ◽  
Atomic Physics ◽  
Velocity Fields ◽  
Spectral Lines ◽  
Inhomogeneous Structure ◽  
The Sun ◽  
Line Profiles ◽  
Physical Phenomena

Observations of the shapes and intensities of spectral lines provide a bounty of information about the outer layers of the sun. In order to utilize this information, however, one is faced with a seemingly monumental task. The sun’s chromosphere and corona are extremely complex, and the underlying physical phenomena are far from being understood. Velocity fields, magnetic fields, Inhomogeneous structure, hydromagnetic phenomena – these are some of the complications that must be faced. Other uncertainties involve the atomic physics upon which all of the deductions depend.

Central kiloparsec of NGC 1326 observed with SINFONI

2020 ◽  
Vol 638 ◽  
pp. A53
Author(s):  
Nastaran Fazeli ◽  
Gerold Busch ◽  
Andreas Eckart ◽  
Françoise Combes ◽  
Persis Misquitta ◽  
...  
Keyword(s):  
Black Hole ◽  
Galaxy Evolution ◽  
Near Infrared ◽  
Velocity Fields ◽  
Molecular Gas ◽  
Nearby Galaxy ◽  
Stellar Content ◽  
Stellar Rotation ◽  
Supermassive Black Hole ◽  
Integral Field Spectrograph

Gas inflow processes in the vicinity of galactic nuclei play a crucial role in galaxy evolution and supermassive black hole growth. Exploring the central kiloparsec of galaxies is essential to shed more light on this subject. We present near-infrared H- and K-band results of the nuclear region of the nearby galaxy NGC 1326, observed with the integral-field spectrograph SINFONI mounted on the Very Large Telescope. The field of view covers 9″ × 9″ (650 × 650 pc2). Our work is concentrated on excitation conditions, morphology, and stellar content. The nucleus of NGC 1326 was classified as a LINER, however in our data we observed an absence of ionised gas emission in the central r ∼ 3″. We studied the morphology by analysing the distribution of ionised and molecular gas, and thereby detected an elliptically shaped, circum-nuclear star-forming ring at a mean radius of 300 pc. We estimate the starburst regions in the ring to be young with dominating ages of < 10 Myr. The molecular gas distribution also reveals an elongated east to west central structure about 3″ in radius, where gas is excited by slow or mild shock mechanisms. We calculate the ionised gas mass of 8 × 105 M⊙ completely concentrated in the nuclear ring and the warm molecular gas mass of 187 M⊙, from which half is concentrated in the ring and the other half in the elongated central structure. The stellar velocity fields show pure rotation in the plane of the galaxy. The gas velocity fields show similar rotation in the ring, but in the central elongated H2 structure they show much higher amplitudes and indications of further deviation from the stellar rotation in the central 1″ aperture. We suggest that the central 6″ elongated H2 structure might be a fast-rotating central disc. The CO(3–2) emission observations with the Atacama Large Millimeter/submillimeter Array reveal a central 1″ torus. In the central 1″ of the H2 velocity field and residual maps, we find indications for a further decoupled structure closer to a nuclear disc, which could be identified with the torus surrounding the supermassive black hole.

Comparative study of NOTES alone vs. NOTES guided by a new image registration system for navigation in the mediastinum: A study in a porcine model

Endoscopy ◽  
2012 ◽  
Vol 44 (10) ◽  
Author(s):  
H Córdova ◽  
R San José Estépar ◽  
A Rodríguez-D'Jesús ◽  
G Martínez-Pallí ◽  
P Arguis ◽  
...  
Keyword(s):  
Image Registration ◽  
Comparative Study ◽  
Porcine Model ◽  
Registration System
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