# Why function gradmag isn´t working for me?

7 visualizaciones (últimos 30 días)
Veronika el 29 de Mzo. de 2017
Respondida: Cris Luengo el 20 de Jul. de 2018
Dear all,
I have this code:
% dip_initialise
%dipsetpref('imagefilepath','/Applications/MATLAB_R2015b.app/toolbox/dip/images')
img = rgb2gray(img1);
x = 350+350*cos(0:0.1:2*pi)';
y = 350+350*sin(0:0.1:2*pi)';
imshow(img1);
hold on
plot([x;x(1)],[y;y(1)],'g')
alpha = 0.001;
beta = 0.9;
gamma = 100;
iterations = 50;
N = length(x);
a = gamma*(2*alpha+6*beta)+1;
b = gamma*(-alpha-4*beta);
c = gamma*beta;
P = diag(repmat(a,1,N));
P = P + diag(repmat(b,1,N-1), 1) + diag( b, -N+1);
P = P + diag(repmat(b,1,N-1),-1) + diag( b, N-1);
P = P + diag(repmat(c,1,N-2), 2) + diag([c,c],-N+2);
P = P + diag(repmat(c,1,N-2),-2) + diag([c,c], N-2);
P = inv(P);
for ii = 1:iterations
% Calculate external force
coords = [x,y];
fex = get_subpixel(f{1},coords,'linear');
fey = get_subpixel(f{2},coords,'linear');
% Move control points
x = P*(x+gamma*fex);
y = P*(y+gamma*fey);
if mod(ii,5)==0
plot([x;x(1)],[y;y(1)],'b')
end
end
plot([x;x(1)],[y;y(1)],'r')
hold off
for segmentation, but this error appears:
Error in ct_snakes (line 32)
##### 0 comentariosMostrar -2 comentarios más antiguosOcultar -2 comentarios más antiguos

Iniciar sesión para comentar.

### Respuestas (2)

Richard Zappulla el 30 de Mzo. de 2017
gradmag is not standard MATLAB function. If downloaded it from the file exchange or GITHUB, make sure the folder in which it resides is on your path. Chances are, this is the issue causing the error you listed.
For convenience, here is the link to the MATLAB page describing how to add a folder to your path.
##### 0 comentariosMostrar -2 comentarios más antiguosOcultar -2 comentarios más antiguos

Iniciar sesión para comentar.

Cris Luengo el 20 de Jul. de 2018
This code, which you have copied from my blog, requires DIPimage to run. Get it here: http://www.diplib.org/. Make sure you read the installation instructions.
##### 0 comentariosMostrar -2 comentarios más antiguosOcultar -2 comentarios más antiguos

Iniciar sesión para comentar.

### Categorías

Más información sobre Clustering en Help Center y File Exchange.

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by