Rank: 222 based on 380 downloads (last 30 days) and 1 file submitted
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Yan Zhang

E-mail
Company/University
University of Central Lancashire

Personal Profile:

Awarded PhD degree in 2006 in the areas of computer vision and pattern recognition at the University of Central Lancashire. Since then, working as a postdoc at the same institute focusing on multi-dimensional and multi-modality medical data processing dedicated to image guided radiotherapy.

Professional Interests:
medical image processing, computer vision, variational/PDE models for data processing, pattern recognition and machine learning

 

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03 Sep 2009 Screenshot 2D/3D image segmentation toolbox 2D/3D image segmentation using level-set based active contour/surface with AOS scheme Author: Yan Zhang active contoursurface, aos, 2d and 3d fast marchi..., levelset, curvature flow, hybrid snake model 380 30
  • 4.77778
4.8 | 9 ratings
Comments and Ratings by Yan View all
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30 Jan 2010 2D/3D image segmentation toolbox 2D/3D image segmentation using level-set based active contour/surface with AOS scheme Author: Yan Zhang

To Yusuke,

The toolbox contains a AOS solver for the PDE in the form of u_t = div( g |\nabla u| ). This is a challenging problem because using explicit finite difference method (FDM) can cause unstability if the time step is too large.

For the PDE you mentioned, simple explicit FDM such as
u_(k+1) = u_k + delta_t * div(V)
should be working no matter how large delta_t is (of course the accuracy will be affected). The above scheme can be easily implemented in Matlab.

Hope this can help.
30 Jan 2010 2D/3D image segmentation toolbox 2D/3D image segmentation using level-set based active contour/surface with AOS scheme Author: Yan Zhang

To Jenny,

The figure you mentioned was produced by a visualization software called Amira. As far as I know, the current matlab graphic toolbox doesn't support volume rendering.

22 Nov 2009 2D/3D image segmentation toolbox 2D/3D image segmentation using level-set based active contour/surface with AOS scheme Author: Yan Zhang

Hi Alex,

The problem has been fully discussed before, please see the previous comments for the details. In brief, go to the source file ac_distance_transform_3d.cpp, and get rid of the string in std::exception.

16 Oct 2009 2D/3D image segmentation toolbox 2D/3D image segmentation using level-set based active contour/surface with AOS scheme Author: Yan Zhang

Hi Eran,

To answer your first question, let' s use u to represent the level-set, normally we use curvature flow to smooth the curve
u_t = div(\nabla u/|\nabla u|)
In my implementation, I do this in two steps:
(1) Make |\nabla u| = 1 using reinitialization (ac_reinit).
(2) With (1) the above equation can be simplified to
u_t = div(\nabla u) = \del u (the Laplacian of u)
which describes the linear diffusion of the level-set.
It's more efficient than solving the more general PDE
u_t = div(g \nabla u/|\nabla u|)
which leads to the answer to your second question --- you should look into the codes in "ac_GAC_model" (AOS implementation for geodesic active contour) that tells exactly how to integrate edge information.

08 Sep 2009 2D/3D image segmentation toolbox 2D/3D image segmentation using level-set based active contour/surface with AOS scheme Author: Yan Zhang

Hi Marco,

Thanks for your advices. For your Point 1, it's a strange problem, the file did pass my gcc 4.4 compiler on MacOSX. Then I tried to compile it on Ubuntu with the same compiler and it failed as you pointed out. As for Point 2, it's totally my fault.
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26 Feb 2010 2D/3D image segmentation toolbox 2D/3D image segmentation using level-set based active contour/surface with AOS scheme Author: Yan Zhang li, baoyun

Dr. Zhang:

Seems you renitilize level set at each step.
However, if not using narrow band, reintilization is very time consumming. Can I reinilized by narrowband and still use your AOS codes?

If use narrowband, how should I use AOS? I read the "fast geodesic levelset" paper, but don't understand how to apply AOS on Narrow band.

Thanks
Baoyun
22 Feb 2010 2D/3D image segmentation toolbox 2D/3D image segmentation using level-set based active contour/surface with AOS scheme Author: Yan Zhang Brophy, Mark

Hi Yan, thanks very much for the great software.

I am using your geodesic active contour model for 3d reconstruction. My problem is that I am having trouble updating the 'g' values on the surface. I have attempted to extract the surface using both Matlab's built-in isosurface and zy_binary_boundary_detection(uint8(phi>0)), but both of these commands only return a subset of the points on the surface. Basically, when I evolve the 3d surface, only a subset of the points 'move', so to speak.

Do you know how I might all points on the surface?

Cheers,
-Mark
18 Feb 2010 2D/3D image segmentation toolbox 2D/3D image segmentation using level-set based active contour/surface with AOS scheme Author: Yan Zhang khelifi, adel

Hi Yan Zhang,
i'm use Windows system,
when I used compile_mex_codes to compile, I met the following errors:

Error: Compile of 'ac_tridiagonal_Thomas_dll.cpp' failed.
 ??? Error using ==> mex at 221
Unable to complete successfully.
Error in ==> compile_mex_codes at 1
mex ac_tridiagonal_Thomas_dll.cpp
Error in ==> run at 57
          evalin('caller', [s ';']);
****************************************************************
i'm read this message
""a more complete version of the toolbox can be downloaded from the following link:
http://ecson.org/resources/software/_AOSLevelsetSegmentationToolbox.zip ""

please help me.

30 Jan 2010 2D/3D image segmentation toolbox 2D/3D image segmentation using level-set based active contour/surface with AOS scheme Author: Yan Zhang Zhang, Yan

To Yusuke,

The toolbox contains a AOS solver for the PDE in the form of u_t = div( g |\nabla u| ). This is a challenging problem because using explicit finite difference method (FDM) can cause unstability if the time step is too large.

For the PDE you mentioned, simple explicit FDM such as
u_(k+1) = u_k + delta_t * div(V)
should be working no matter how large delta_t is (of course the accuracy will be affected). The above scheme can be easily implemented in Matlab.

Hope this can help.
30 Jan 2010 2D/3D image segmentation toolbox 2D/3D image segmentation using level-set based active contour/surface with AOS scheme Author: Yan Zhang Zhang, Yan

To Jenny,

The figure you mentioned was produced by a visualization software called Amira. As far as I know, the current matlab graphic toolbox doesn't support volume rendering.

Top Tags Applied by Yan
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2d and 3d fast marching, 2d3d image segmentation, active contoursurface, aos, chanvese model
Files Tagged by Yan
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Updated   File Tags Downloads
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03 Sep 2009 Screenshot 2D/3D image segmentation toolbox 2D/3D image segmentation using level-set based active contour/surface with AOS scheme Author: Yan Zhang active contoursurface, aos, 2d and 3d fast marchi..., levelset, curvature flow, hybrid snake model 380 30
  • 4.77778
4.8 | 9 ratings
 

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