Rank: 398 based on 277 downloads (last 30 days) and 4 files submitted
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Daniel Lopes

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03 Jan 2013 Screenshot Are Two Ellipsoids in Contact? Algebraic Separation Condition for Ellipsoids An algebraic expression for characterizing the 3-D spatial configurations formed by two ellipsoids. Author: Daniel Lopes collision detection, ellipsoid, proximity query, contact detection 14 0
06 Nov 2007 drawline Draws line segments on a image matrix. Author: Daniel Lopes annotation, customization, line, draw, image, label 14 7
  • 4.28571
4.3 | 7 ratings
16 May 2007 Anisotropic Diffusion (Perona & Malik) A set of filters that perform 1D, 2D and 3D conventional anisotropic diffusion (gray scale data). Author: Daniel Lopes filtering, anisotropic, diffusion, perona, malik, scalespace 243 30
  • 4.36364
4.4 | 22 ratings
08 May 2007 beepbeep Creates sound composed by OS beeps. Author: Daniel Lopes beep, audio, alarm, warning, sound 6 1
  • 2.0
2.0 | 1 rating
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18 Mar 2013 Determination of the minimum distance between two SuperEllipsoids surfaces. Using Optimization Optimization method to determine the minimum distance (or max overlap) between two SuperEllipsoids? Author: Ricardo Portal

Nice job! The code looks very tidy and neat.

28 Feb 2013 boundedline.m Plot one or more lines with a shaded boundary (can represent error, confidence intervals, etc). Author: Kelly Kearney

Works like a charm! Great code.

27 Aug 2012 Ellipsoid fit Fits an ellipsoid to data using linear least squares. Author: Yury

Well done!

27 Aug 2012 Sphere Fit (least squared) Fits a sphere to a set of noisy data. Does not require a wide arc or many points. Author: Alan Jennings

Great piece of code!

25 Sep 2011 NURBS Toolbox by D.M. Spink NURBS Toolbox by D.M. Spink re-uploaded. The previous link has broken. Author: Paul

There are bugs that make this toolbox uncompatible with the Nurbs2IGES
(http://www.mathworks.com/matlabcentral/fileexchange/12087-nurbs2iges).

Comments and Ratings on Daniel Lopes' Files View all
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27 Nov 2014 Anisotropic Diffusion (Perona & Malik) A set of filters that perform 1D, 2D and 3D conventional anisotropic diffusion (gray scale data). Author: Daniel Lopes Sebastian

Nice contribution.

For those using anisodiff1D, consider replacing imfilter(.,.,'conv') by conv(.,.,'same'). It's quite faster.

24 Nov 2014 Anisotropic Diffusion (Perona & Malik) A set of filters that perform 1D, 2D and 3D conventional anisotropic diffusion (gray scale data). Author: Daniel Lopes Royi Avital

I think you only applied the Divergence operator once when you should apply it twice.

13 Jun 2014 Anisotropic Diffusion (Perona & Malik) A set of filters that perform 1D, 2D and 3D conventional anisotropic diffusion (gray scale data). Author: Daniel Lopes Stefan Karlsson

There is no productive 2D example provided that show the superiority of this method over regular gaussian smoothing. A simple combination of Gaussian and Median filtering provides better denoising than what is proposed:

s = phantom(512) + randn(512);
num_iter = 55;
delta_t = 1/7;
kappa = 30;
option = 2;
ad = anisodiff2D(s,num_iter,delta_t,kappa,option);

It is very likely that the authors generalization of using 8 point neighbourhoods is valid, but if so it changes the valid range of the parameters, and thus one cant easily recreate the results of the original Perona-Malik paper. If a simple example was provided that showed how the 2D method actually outperforms gaussian blurring, then I might be inclined to read the secondary paper referenced.

the interpretation of the kappa parameter is nicely given in weickerts book: http://www.lpi.tel.uva.es/muitic/pim/docus/anisotropic_diffusion.pdf, chapter 1, figure 1.1, b... (its called lambda there)

I cant get that interpretation to work for me here. Whats wrong? How can i strengthen the edges in the image using this, while blurring along isolines!?

Again, if only a positive example was provided for the 2D case, this might all be cleared up.

28 Apr 2014 Anisotropic Diffusion (Perona & Malik) A set of filters that perform 1D, 2D and 3D conventional anisotropic diffusion (gray scale data). Author: Daniel Lopes SHANYUE

19 Dec 2013 Anisotropic Diffusion (Perona & Malik) A set of filters that perform 1D, 2D and 3D conventional anisotropic diffusion (gray scale data). Author: Daniel Lopes jia

very clear and have many details about the algorithm

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