Apologize for the following simple question. What exactly does the sigma data mean from the example given? The first Sigma (1,1) is the sigma for the first estimated cluster and the second sigma (2,2) is for the first estimated cluster on the second row ??
Could you please clarify? Thanks.
>> model.Sigma
ans(:,:,1) =
0.7227 0.8439
0.8439 1.8252
ans(:,:,2) =
0.2629 -0.1116
-0.1116 0.2411
ans(:,:,3) =
0.4209 -0.0600
-0.0600 0.0967
21 Sep 2010
EM_GM
An expectation maximization algorithm for learning a multi-dimensional Gaussian mixture.
Author: Patrick Tsui
When i run I get this error, Is there something else that i need to do before running this. Am running matlab 7.8.0 R2009a
>> X = zeros(600,2);
>> X(1:200,:) = normrnd(0,1,200,2);
>> X(201:400,:) = normrnd(0,2,200,2);
X(401:600,:) = normrnd(0,3,200,2);
>> [W,M,V,L] = EM_GM(X,3,[],[],1,[])
??? Cell contents reference from a non-cell array object.
Error in ==> getdim at 13
d = getdim(carray{i});
Error in ==> rand at 12
d = getdim(c);
Error in ==> randsample at 95
x(ceil(n * rand(1,k-sumx))) = 1; % sample w/replacement
Error in ==> kmeans at 321
Xsubset = X(randsample(n,floor(.1*n)),:);
Error in ==> EM_GM>Init_EM at 261
[Ci,C] = kmeans(X,k,'Start','cluster', ...
Error in ==> EM_GM at 74
[W,M,V] = Init_EM(X,k); L = 0;
Greetings Prof., Very nice .. could you please let me know what exactly does the mask variable store ? As what i see it classifies each pixel that falls within each class . Am i correct in that assumption?
Some people want to know how to view the segmented image. For example suppose you have two classes ie k=2; us the following code to view it
[row col] = size(ima);
final_img = zeros(row,col);
for i=1:row
for j=1:col
if mask(i,j)==1
final_img(i,j)=1;
else
final_img(i,j)=255;
end
end
end
imshow(final_img/255);
This is a naive way of viewing it .. you may have to change somethings if k>2. Anywayz hope it helps. The mask basically stores the segmented image.
4
16 Nov 2011
EM image segmentation
Apllication of EM algorithm to segment a grey scale image on diferent classes
Sir, I am starting my project on the same subject. i was unable to find the algorithm psuedocode for em algorithm. kindly send me one at rprashanth31@gmail.com. Also can u just tell me the explanation for the source code..
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