Rank: 491 based on 194 downloads (last 30 days) and 4 files submitted
photo

Daniel Lopes

E-mail

Personal Profile:
Professional Interests:
Medical Image Processing, Geometric Modeling, Computer Vision, Computer Graphics, Scientific Visualization

 

Watch this Author's files

 

Files Posted by Daniel View all
Updated   File Tags Downloads
(last 30 days)
Comments Rating
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 15 0
06 Nov 2007 drawline Draws line segments on a image matrix. Author: Daniel Lopes annotation, customization, line, draw, image, label 24 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 149 28
  • 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
Comments and Ratings by Daniel View all
Updated File Comments Rating
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: line plots with shaded error/confidence intervals 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 Petrov

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's Files View all
Updated File Comment by Comments Rating
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 Karlsson, Stefan

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

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

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

I ve tried the code it is very useful bt i want to generate diffusion function to calculate flux function hw to do?

Contact us