% Copyright or © or Copr. CREATIS laboratory, Lyon, France.
% Contributor: Olivier Bernard, Associate Professor at the french
% engineering university INSA (Institut National des Sciences Appliquees)
% and a member of the CREATIS-LRMN laboratory (CNRS 5220, INSERM U630,
% INSA, Claude Bernard Lyon 1 University) in France (Lyon).
% Date of creation: 8th of October 2009
% E-mail of the author: email@example.com
% This software is a computer program whose purpose is to evaluate the
% performance of different level-set based segmentation algorithms in the
% context of image processing (and more particularly on biomedical
% The software has been designed for two main purposes.
% - firstly, CREASEG allows you to use six different level-set methods.
% These methods have been chosen in order to work with a wide range of
% level-sets. You can select for instance classical methods such as
% Caselles or Chan & Vese level-set, or more recent approaches such as the
% one developped by Lankton or Bernard.
% - finally, the software allows you to compare the performance of the six
% level-set methods on different images. The performance can be evaluated
% either visually, or from measurements (either using the Dice coefficient
% or the PSNR value) between a reference and the results of the
% The level-set segmentation platform is citationware. If you are
% publishing any work, where this program has been used, or which used one
% of the proposed level-set algorithms, please remember that it was
% obtained free of charge. You must reference the papers shown below and
% the name of the CREASEG software must be mentioned in the publication.
% CREASEG software
% "T. Dietenbeck, M. Alessandrini, D. Friboulet, O. Bernard. CREASEG: a
% free software for the evaluation of image segmentation algorithms based
% on level-set. In IEEE International Conference On Image Processing.
% Hong Kong, China, 2010."
% Bernard method
% "O. Bernard, D. Friboulet, P. Thevenaz, M. Unser. Variational B-Spline
% Level-Set: A Linear Filtering Approach for Fast Deformable Model
% Evolution. In IEEE Transactions on Image Processing. volume 18, no. 06,
% pp. 1179-1191, 2009."
% Caselles method
% "V. Caselles, R. Kimmel, and G. Sapiro. Geodesic active contours.
% International Journal of Computer Vision, volume 22, pp. 61-79, 1997."
% Chan & Vese method
% "T. Chan and L. Vese. Active contours without edges. IEEE Transactions on
% Image Processing. volume10, pp. 266-277, February 2001."
% Lankton method
% "S. Lankton, A. Tannenbaum. Localizing Region-Based Active Contours. In
% IEEE Transactions on Image Processing. volume 17, no. 11, pp. 2029-2039,
% Li method
% "C. Li, C.Y. Kao, J.C. Gore, Z. Ding. Minimization of Region-Scalable
% Fitting Energy for Image Segmentation. In IEEE Transactions on Image
% Processing. volume 17, no. 10, pp. 1940-1949, 2008."
% Shi method
% "Yonggang Shi, William Clem Karl. A Real-Time Algorithm for the
% Approximation of Level-Set-Based Curve Evolution. In IEEE Transactions
% on Image Processing. volume 17, no. 05, pp. 645-656, 2008."
% This software is governed by the BSD license and
% abiding by the rules of distribution of free software.
% As a counterpart to the access to the source code and rights to copy,
% modify and redistribute granted by the license, users are provided only
% with a limited warranty and the software's author, the holder of the
% economic rights, and the successive licensors have only limited
% In this respect, the user's attention is drawn to the risks associated
% with loading, using, modifying and/or developing or reproducing the
% software by the user in light of its specific status of free software,
% that may mean that it is complicated to manipulate, and that also
% therefore means that it is reserved for developers and experienced
% professionals having in-depth computer knowledge. Users are therefore
% encouraged to load and test the software's suitability as regards their
% requirements in conditions enabling the security of their systems and/or
% data to be ensured and, more generally, to use and operate it in the
% same conditions as regards security.
function [xs, ys] = creaseg_spline(x, y)
%-- "Looping" the points to have a nice closed contour
i = 7; %-- Number of extra points added
if length(x) > i %-- Check if the number of point is sufficient
x = [x x(1:i)]; y = [y y(1:i)];
i2 = i-length(x);
x = [x x]; y = [y y];
x = [x x(1:i2)]; y = [y y(1:i2)];
s_div = 1/10;
t = 1:length(x);
ts = 1:s_div:length(x);
xs = spline(t,x,ts);
ys = spline(t,y,ts);
%-- Deleting the extra segment (at the begining and at the end)
xs = xs(ceil(i/2)/s_div:(length(x)-floor(i/2))/s_div);
ys = ys(ceil(i/2)/s_div:(length(x)-floor(i/2))/s_div);