Segmentation for CT Image Based on Improved Level-Set Approach

2008 ◽  
Author(s):  
Qiangjun Xie ◽  
Xufeng Chen ◽  
Li Ma ◽  
Zekui Zhou
Keyword(s):  
Level Set ◽  
Ct Image ◽  
Level Set Approach

scholarly journals Automatic Global Level Set Approach for Lumbar Vertebrae CT Image Segmentation

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Yang Li ◽  
Wei Liang ◽  
Yinlong Zhang ◽  
Jindong Tan
Keyword(s):  
Image Segmentation ◽  
Level Set ◽  
Lumbar Vertebrae ◽  
Ct Image ◽  
Global Level ◽  
Level Set Function ◽  
Weak Boundary ◽  
Irregular Boundaries ◽  
Set Function ◽  
Level Set Approach

Vertebrae computed tomography (CT) image automatic segmentation is an essential step for Image-guided minimally invasive spine surgery. However, most of state-of-the-art methods still require human intervention due to the inherent limitations of vertebrae CT image, such as topological variation, irregular boundaries (double boundary, weak boundary), and image noise. Therefore, this paper intentionally designed an automatic global level set approach (AGLSA), which is capable of dealing with these issues for lumbar vertebrae CT image segmentation. Unlike the traditional level set methods, we firstly propose an automatically initialized level set function (AILSF) that comprises hybrid morphological filter (HMF) and Gaussian mixture model (GMM) to automatically generate a smooth initial contour which is precisely adjacent to the object boundary. Secondly, a regularized level set formulation is introduced to overcome the weak boundary leaking problem, which utilizes the region correlation of histograms inside and outside the level set contour as a global term. Ultimately, a gradient vector flow (GVF) based edge-stopping function is employed to guarantee a fast convergence rate of the level set evolution and to avoid level set function oversegmentation at the same time. Our proposed approach has been tested on 115 vertebrae CT volumes of various patients. Quantitative comparisons validate that our proposed AGLSA is more accurate in segmenting lumbar vertebrae CT images with irregular boundaries and more robust to various levels of salt-and-pepper noise.

Two-phase flow stability analysis using a level set approach

2017 ◽  
Author(s):  
Mamta Raju Jotkar ◽  
Daniel Rodriguez ◽  
Bruno Marins Soares
Keyword(s):  
Stability Analysis ◽  
Level Set ◽  
Two Phase Flow ◽  
Flow Stability ◽  
Phase Flow ◽  
Two Phase ◽  
Level Set Approach

Hydrodynamic simulation of air bubble implosion using a level set approach

2006 ◽  
Vol 215 (1) ◽  
pp. 98-132 ◽  
Author(s):  
Sunitha Nagrath ◽  
Kenneth Jansen ◽  
Richard T. Lahey ◽  
Iskander Akhatov
Keyword(s):  
Level Set ◽  
Hydrodynamic Simulation ◽  
Air Bubble ◽  
Level Set Approach

Modeling of discrete intersecting discontinuities in rock mass using XFEM/level set approach

2016 ◽  
pp. 239-246
Author(s):  
Kamal Das ◽  
Sandeep Sandha ◽  
Eduardo Rodrigues ◽  
U Mello ◽  
Ignacio Carol ◽  
...  
Keyword(s):  
Rock Mass ◽  
Level Set ◽  
Level Set Approach

Numerical Modelling of Plastic Deformation and Subsequent Recrystallization in Polycrystalline Materials, Based on a Digital Material Framework

2007 ◽  
Vol 558-559 ◽  
pp. 1133-1138 ◽  
Author(s):  
Roland E. Logé ◽  
M. Bernacki ◽  
H. Resk ◽  
H. Digonnet ◽  
T. Coupez
Keyword(s):  
Level Set ◽  
Large Strain ◽  
Voronoi Tessellation ◽  
Constitutive Law ◽  
Polycrystalline Materials ◽  
Large Strains ◽  
Element Mesh ◽  
Digital Material ◽  
Digital Sample ◽  
Level Set Approach

The development of a digital material framework is presented, allowing to build virtual microstructures in agreement with experimental data. The construction of the virtual material consists in building a multi-level Voronoï tessellation. A polycrystalline microstructure made of grains and sub-grains can be obtained in a random or deterministic way. A corresponding finite element mesh can be generated automatically in 3D, and used for the simulation of mechanical testing under large strain. In the examples shown in this work, the initial mesh was non uniform and anisotropic, taking into account the presence of interfaces between grains and sub-grains. Automatic remeshing was performed due to the large strains, and maintained the non uniform and anisotropic character of the mesh. A level set approach was used to follow the grain boundaries during the deformation. The grain constitutive law was either a viscoplastic power law, or a crystallographic formulation based on crystal plasticity. Stored energies and precise grain boundary network geometries were obtained directly from the deformed digital sample. This information was used for subsequent modelling of grain growth with the level set approach, on the same mesh.

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